[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14707902361536,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14707902365824,
    "event_type": "GoCreate",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14707902372992,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14707902376512,
    "event_type": "GoCreate",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14707902384320,
    "event_type": "GoCreate",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14707902387264,
    "event_type": "GoStart",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14707902390208,
    "event_type": "GoCreate",
    "goroutine_id": 11,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14707902391488,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14707902392000,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 8,
  "timestamp_ns": 14707902392000,
  "event_type": "GoStart",
  "goroutine_id": 9,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "11": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "8": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 10}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14707902361536,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14707902365824,
    "event_type": "GoCreate",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14707902372992,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14707902376512,
    "event_type": "GoCreate",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14707902384320,
    "event_type": "GoCreate",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14707902387264,
    "event_type": "GoStart",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14707902390208,
    "event_type": "GoCreate",
    "goroutine_id": 11,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14707902391488,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14707902392000,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 8,
  "timestamp_ns": 14707902392000,
  "event_type": "GoStart",
  "goroutine_id": 9,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "11": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "8": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 20}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14707902361536,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14707902365824,
    "event_type": "GoCreate",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14707902372992,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14707902376512,
    "event_type": "GoCreate",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14707902384320,
    "event_type": "GoCreate",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14707902387264,
    "event_type": "GoStart",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14707902390208,
    "event_type": "GoCreate",
    "goroutine_id": 11,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14707902391488,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14707902392000,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 8,
  "timestamp_ns": 14707902392000,
  "event_type": "GoStart",
  "goroutine_id": 9,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "11": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "8": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoUnblock", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14707902361536,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14707902365824,
    "event_type": "GoCreate",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14707902372992,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14707902376512,
    "event_type": "GoCreate",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14707902384320,
    "event_type": "GoCreate",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14707902387264,
    "event_type": "GoStart",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14707902390208,
    "event_type": "GoCreate",
    "goroutine_id": 11,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14707902391488,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14707902392000,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 8,
  "timestamp_ns": 14707902392000,
  "event_type": "GoStart",
  "goroutine_id": 9,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "11": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "8": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 10}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14707902361536,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14707902365824,
    "event_type": "GoCreate",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14707902372992,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14707902376512,
    "event_type": "GoCreate",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14707902384320,
    "event_type": "GoCreate",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14707902387264,
    "event_type": "GoStart",
    "goroutine_id": 8,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14707902390208,
    "event_type": "GoCreate",
    "goroutine_id": 11,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14707902391488,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14707902392000,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "11": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "8": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 8,
  "timestamp_ns": 14707902392000,
  "event_type": "GoStart",
  "goroutine_id": 9,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "11": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "8": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoUnblock", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 9,
    "timestamp_ns": 14706833802496,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14706833812544,
    "event_type": "GoBlock",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14706833816768,
    "event_type": "GoStart",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14706833818432,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14706833819072,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14706833821696,
    "event_type": "GoBlock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14706833822080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14706833823104,
    "event_type": "GoUnblock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14706833823424,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 18,
    "timestamp_ns": 14706833823616,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "11": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 18,
  "timestamp_ns": 14706833823616,
  "event_type": "GoStart",
  "goroutine_id": 10,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "11": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.traceStartReadCPU"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoUnblock", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 9,
    "timestamp_ns": 14706833802496,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14706833812544,
    "event_type": "GoBlock",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14706833816768,
    "event_type": "GoStart",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14706833818432,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14706833819072,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14706833821696,
    "event_type": "GoBlock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14706833822080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14706833823104,
    "event_type": "GoUnblock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14706833823424,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 18,
    "timestamp_ns": 14706833823616,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "11": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 18,
  "timestamp_ns": 14706833823616,
  "event_type": "GoStart",
  "goroutine_id": 10,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "11": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.traceStartReadCPU"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 11}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 9,
    "timestamp_ns": 14706833802496,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14706833812544,
    "event_type": "GoBlock",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14706833816768,
    "event_type": "GoStart",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14706833818432,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14706833819072,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14706833821696,
    "event_type": "GoBlock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14706833822080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14706833823104,
    "event_type": "GoUnblock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14706833823424,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 18,
    "timestamp_ns": 14706833823616,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "11": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 18,
  "timestamp_ns": 14706833823616,
  "event_type": "GoStart",
  "goroutine_id": 10,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "11": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.traceStartReadCPU"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 9}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 9,
    "timestamp_ns": 14706833802496,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14706833812544,
    "event_type": "GoBlock",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14706833816768,
    "event_type": "GoStart",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14706833818432,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14706833819072,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14706833821696,
    "event_type": "GoBlock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14706833822080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14706833823104,
    "event_type": "GoUnblock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14706833823424,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 18,
    "timestamp_ns": 14706833823616,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "11": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 18,
  "timestamp_ns": 14706833823616,
  "event_type": "GoStart",
  "goroutine_id": 10,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "11": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.traceStartReadCPU"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 23}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 9,
    "timestamp_ns": 14706833802496,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14706833812544,
    "event_type": "GoBlock",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14706833816768,
    "event_type": "GoStart",
    "goroutine_id": 11,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14706833818432,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14706833819072,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14706833821696,
    "event_type": "GoBlock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14706833822080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14706833823104,
    "event_type": "GoUnblock",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14706833823424,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 18,
    "timestamp_ns": 14706833823616,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "chan send",
        "locals_hint": "runtime.chansend1"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "11": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 18,
  "timestamp_ns": 14706833823616,
  "event_type": "GoStart",
  "goroutine_id": 10,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "chan send",
      "locals_hint": "runtime.chansend1"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "11": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.traceStartReadCPU"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 35}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 18,
    "timestamp_ns": 14708974025856,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 19,
    "timestamp_ns": 14708974026112,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 20,
    "timestamp_ns": 14708974033344,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 21,
    "timestamp_ns": 14708974036416,
    "event_type": "GoStart",
    "goroutine_id": 22,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 22,
    "timestamp_ns": 14708974037184,
    "event_type": "GoBlock",
    "goroutine_id": 19,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 23,
    "timestamp_ns": 14708974038080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 24,
    "timestamp_ns": 14708974038720,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 25,
    "timestamp_ns": 14708974039680,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 26,
    "timestamp_ns": 14708974043968,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 27,
    "timestamp_ns": 14708974044864,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sleep",
        "locals_hint": "time.Sleep"
      },
      "19": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "20": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "21": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "22": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "23": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv2"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 27,
  "timestamp_ns": 14708974044864,
  "event_type": "GoBlock",
  "goroutine_id": 23,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sleep",
      "locals_hint": "time.Sleep"
    },
    "19": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "20": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "21": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "22": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "23": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv2"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoUnblock", "goroutine_id": 21}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 18,
    "timestamp_ns": 14708974025856,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 19,
    "timestamp_ns": 14708974026112,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 20,
    "timestamp_ns": 14708974033344,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 21,
    "timestamp_ns": 14708974036416,
    "event_type": "GoStart",
    "goroutine_id": 22,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 22,
    "timestamp_ns": 14708974037184,
    "event_type": "GoBlock",
    "goroutine_id": 19,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 23,
    "timestamp_ns": 14708974038080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 24,
    "timestamp_ns": 14708974038720,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 25,
    "timestamp_ns": 14708974039680,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 26,
    "timestamp_ns": 14708974043968,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 27,
    "timestamp_ns": 14708974044864,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sleep",
        "locals_hint": "time.Sleep"
      },
      "19": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "20": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "21": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "22": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "23": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv2"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 27,
  "timestamp_ns": 14708974044864,
  "event_type": "GoBlock",
  "goroutine_id": 23,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sleep",
      "locals_hint": "time.Sleep"
    },
    "19": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "20": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "21": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "22": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "23": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv2"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 35}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 18,
    "timestamp_ns": 14708974025856,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 19,
    "timestamp_ns": 14708974026112,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 20,
    "timestamp_ns": 14708974033344,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 21,
    "timestamp_ns": 14708974036416,
    "event_type": "GoStart",
    "goroutine_id": 22,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 22,
    "timestamp_ns": 14708974037184,
    "event_type": "GoBlock",
    "goroutine_id": 19,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 23,
    "timestamp_ns": 14708974038080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 24,
    "timestamp_ns": 14708974038720,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 25,
    "timestamp_ns": 14708974039680,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 26,
    "timestamp_ns": 14708974043968,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 27,
    "timestamp_ns": 14708974044864,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sleep",
        "locals_hint": "time.Sleep"
      },
      "19": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "20": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "21": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "22": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "23": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv2"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 27,
  "timestamp_ns": 14708974044864,
  "event_type": "GoBlock",
  "goroutine_id": 23,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sleep",
      "locals_hint": "time.Sleep"
    },
    "19": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "20": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "21": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "22": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "23": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv2"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 18,
    "timestamp_ns": 14708974025856,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 19,
    "timestamp_ns": 14708974026112,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 20,
    "timestamp_ns": 14708974033344,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 21,
    "timestamp_ns": 14708974036416,
    "event_type": "GoStart",
    "goroutine_id": 22,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 22,
    "timestamp_ns": 14708974037184,
    "event_type": "GoBlock",
    "goroutine_id": 19,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 23,
    "timestamp_ns": 14708974038080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 24,
    "timestamp_ns": 14708974038720,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 25,
    "timestamp_ns": 14708974039680,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 26,
    "timestamp_ns": 14708974043968,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 27,
    "timestamp_ns": 14708974044864,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sleep",
        "locals_hint": "time.Sleep"
      },
      "19": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "20": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "21": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "22": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "23": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv2"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 27,
  "timestamp_ns": 14708974044864,
  "event_type": "GoBlock",
  "goroutine_id": 23,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sleep",
      "locals_hint": "time.Sleep"
    },
    "19": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "20": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "21": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "22": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "23": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv2"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 10}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: leak
// concurrency_pattern: channel
// goroutine_count: 3
// expected_nondeterminism: none
// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.

package main

import (
	"fmt"
	"os"
	"runtime/trace"
	"time"
)

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	requests := make(chan int)

	// Two handler goroutines read from requests. They will block in GoWaiting
	// once main stops sending, because main never calls close(requests).
	for i := 0; i < 2; i++ {
		go func(id int) {
			for req := range requests {
				fmt.Printf("handler %d processed request %d\n", id, req)
			}
		}(i)
	}

	// Send three requests then stop — handlers are left waiting for more.
	for i := 0; i < 3; i++ {
		requests <- i
	}

	// Sleep so the trace captures both goroutines in GoWaiting before main exits.
	time.Sleep(50 * time.Millisecond)
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 18,
    "timestamp_ns": 14708974025856,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 19,
    "timestamp_ns": 14708974026112,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 20,
    "timestamp_ns": 14708974033344,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 21,
    "timestamp_ns": 14708974036416,
    "event_type": "GoStart",
    "goroutine_id": 22,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 22,
    "timestamp_ns": 14708974037184,
    "event_type": "GoBlock",
    "goroutine_id": 19,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 23,
    "timestamp_ns": 14708974038080,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 24,
    "timestamp_ns": 14708974038720,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 25,
    "timestamp_ns": 14708974039680,
    "event_type": "GoStart",
    "goroutine_id": 23,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 26,
    "timestamp_ns": 14708974043968,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 27,
    "timestamp_ns": 14708974044864,
    "event_type": "GoBlock",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sleep",
        "locals_hint": "time.Sleep"
      },
      "19": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "20": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "21": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "22": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "23": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv2"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 27,
  "timestamp_ns": 14708974044864,
  "event_type": "GoBlock",
  "goroutine_id": 23,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sleep",
      "locals_hint": "time.Sleep"
    },
    "19": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "20": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "21": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "22": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "23": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv2"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 10}