Update generation_config.json

The model's `generation_config.json` is missing `<|call|>` (token 200012) in the `eos_token_id` list. This causes the model to not stop generation after emitting a tool call, which makes the Harmony parser fail with:

openai_harmony.HarmonyError: Unexpected token 12606 while expecting start token 200006

vLLM's chat completion handler for GPT-OSS models tries to inject the Harmony stop tokens (200002, 200012) via `default_sampling_params`, but `to_sampling_params()` in the request protocol takes `stop_token_ids` directly from the request body (which defaults to `[]`) and never merges the defaults. As a result, the only reliable way to ensure `<|call|>` stops generation is to include it in `eos_token_id` in the model's `generation_config.json`, since the engine always applies those.

The fix adds 200012 (`<|call|>`) to the `eos_token_id` array:

```json
"eos_token_id": [
200002,
200012,
199999
]
```

Without the fix, any request with `tools` fails with a 500 error. With the fix, tool calling works correctly in both streaming and non-streaming modes.

Tested on vLLM v0.18.0 with both BF16 and MXFP4 checkpoints.

generation_config.json

@@ -3,6 +3,7 @@
   "do_sample": true,
   "eos_token_id": [
     200002,
+    200012,
     199999
   ],
   "pad_token_id": 199999,