File size: 31,547 Bytes
2b9afa6
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
"""
Hermes Plugin System
====================

Discovers, loads, and manages plugins from three sources:

1. **User plugins**   – ``~/.hermes/plugins/<name>/``
2. **Project plugins** – ``./.hermes/plugins/<name>/`` (opt-in via
   ``HERMES_ENABLE_PROJECT_PLUGINS``)
3. **Pip plugins**     – packages that expose the ``hermes_agent.plugins``
   entry-point group.

Each directory plugin must contain a ``plugin.yaml`` manifest **and** an
``__init__.py`` with a ``register(ctx)`` function.

Lifecycle hooks
---------------
Plugins may register callbacks for any of the hooks in ``VALID_HOOKS``.
The agent core calls ``invoke_hook(name, **kwargs)`` at the appropriate
points.

Tool registration
-----------------
``PluginContext.register_tool()`` delegates to ``tools.registry.register()``
so plugin-defined tools appear alongside the built-in tools.
"""

from __future__ import annotations

import importlib
import importlib.metadata
import importlib.util
import logging
import sys
import types
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any, Callable, Dict, List, Optional, Set, Union

from hermes_constants import get_hermes_home
from utils import env_var_enabled

try:
    import yaml
except ImportError:  # pragma: no cover – yaml is optional at import time
    yaml = None  # type: ignore[assignment]

logger = logging.getLogger(__name__)

# ---------------------------------------------------------------------------
# Constants
# ---------------------------------------------------------------------------

VALID_HOOKS: Set[str] = {
    "pre_tool_call",
    "post_tool_call",
    "pre_llm_call",
    "post_llm_call",
    "pre_api_request",
    "post_api_request",
    "on_session_start",
    "on_session_end",
    "on_session_finalize",
    "on_session_reset",
}

ENTRY_POINTS_GROUP = "hermes_agent.plugins"

_NS_PARENT = "hermes_plugins"


def _env_enabled(name: str) -> bool:
    """Return True when an env var is set to a truthy opt-in value."""
    return env_var_enabled(name)


def _get_disabled_plugins() -> set:
    """Read the disabled plugins list from config.yaml."""
    try:
        from hermes_cli.config import load_config
        config = load_config()
        disabled = config.get("plugins", {}).get("disabled", [])
        return set(disabled) if isinstance(disabled, list) else set()
    except Exception:
        return set()


# ---------------------------------------------------------------------------
# Data classes
# ---------------------------------------------------------------------------

@dataclass
class PluginManifest:
    """Parsed representation of a plugin.yaml manifest."""

    name: str
    version: str = ""
    description: str = ""
    author: str = ""
    requires_env: List[Union[str, Dict[str, Any]]] = field(default_factory=list)
    provides_tools: List[str] = field(default_factory=list)
    provides_hooks: List[str] = field(default_factory=list)
    source: str = ""        # "user", "project", or "entrypoint"
    path: Optional[str] = None


@dataclass
class LoadedPlugin:
    """Runtime state for a single loaded plugin."""

    manifest: PluginManifest
    module: Optional[types.ModuleType] = None
    tools_registered: List[str] = field(default_factory=list)
    hooks_registered: List[str] = field(default_factory=list)
    commands_registered: List[str] = field(default_factory=list)
    enabled: bool = False
    error: Optional[str] = None


# ---------------------------------------------------------------------------
# PluginContext  – handed to each plugin's ``register()`` function
# ---------------------------------------------------------------------------

class PluginContext:
    """Facade given to plugins so they can register tools and hooks."""

    def __init__(self, manifest: PluginManifest, manager: "PluginManager"):
        self.manifest = manifest
        self._manager = manager

    # -- tool registration --------------------------------------------------

    def register_tool(
        self,
        name: str,
        toolset: str,
        schema: dict,
        handler: Callable,
        check_fn: Callable | None = None,
        requires_env: list | None = None,
        is_async: bool = False,
        description: str = "",
        emoji: str = "",
    ) -> None:
        """Register a tool in the global registry **and** track it as plugin-provided."""
        from tools.registry import registry

        registry.register(
            name=name,
            toolset=toolset,
            schema=schema,
            handler=handler,
            check_fn=check_fn,
            requires_env=requires_env,
            is_async=is_async,
            description=description,
            emoji=emoji,
        )
        self._manager._plugin_tool_names.add(name)
        logger.debug("Plugin %s registered tool: %s", self.manifest.name, name)

    # -- message injection --------------------------------------------------

    def inject_message(self, content: str, role: str = "user") -> bool:
        """Inject a message into the active conversation.

        If the agent is idle (waiting for user input), this starts a new turn.
        If the agent is running, this interrupts and injects the message.

        This enables plugins (e.g. remote control viewers, messaging bridges)
        to send messages into the conversation from external sources.

        Returns True if the message was queued successfully.
        """
        cli = self._manager._cli_ref
        if cli is None:
            logger.warning("inject_message: no CLI reference (not available in gateway mode)")
            return False

        msg = content if role == "user" else f"[{role}] {content}"

        if getattr(cli, "_agent_running", False):
            # Agent is mid-turn — interrupt with the message
            cli._interrupt_queue.put(msg)
        else:
            # Agent is idle — queue as next input
            cli._pending_input.put(msg)
        return True

    # -- CLI command registration --------------------------------------------

    def register_cli_command(
        self,
        name: str,
        help: str,
        setup_fn: Callable,
        handler_fn: Callable | None = None,
        description: str = "",
    ) -> None:
        """Register a CLI subcommand (e.g. ``hermes honcho ...``).

        The *setup_fn* receives an argparse subparser and should add any
        arguments/sub-subparsers.  If *handler_fn* is provided it is set
        as the default dispatch function via ``set_defaults(func=...)``."""
        self._manager._cli_commands[name] = {
            "name": name,
            "help": help,
            "description": description,
            "setup_fn": setup_fn,
            "handler_fn": handler_fn,
            "plugin": self.manifest.name,
        }
        logger.debug("Plugin %s registered CLI command: %s", self.manifest.name, name)

    # -- slash command registration -------------------------------------------

    def register_command(
        self,
        name: str,
        handler: Callable,
        description: str = "",
    ) -> None:
        """Register a slash command (e.g. ``/lcm``) available in CLI and gateway sessions.

        The handler signature is ``fn(raw_args: str) -> str | None``.
        It may also be an async callable — the gateway dispatch handles both.

        Unlike ``register_cli_command()`` (which creates ``hermes <subcommand>``
        terminal commands), this registers in-session slash commands that users
        invoke during a conversation.

        Names conflicting with built-in commands are rejected with a warning.
        """
        clean = name.lower().strip().lstrip("/").replace(" ", "-")
        if not clean:
            logger.warning(
                "Plugin '%s' tried to register a command with an empty name.",
                self.manifest.name,
            )
            return

        # Reject if it conflicts with a built-in command
        try:
            from hermes_cli.commands import resolve_command
            if resolve_command(clean) is not None:
                logger.warning(
                    "Plugin '%s' tried to register command '/%s' which conflicts "
                    "with a built-in command. Skipping.",
                    self.manifest.name, clean,
                )
                return
        except Exception:
            pass  # If commands module isn't available, skip the check

        self._manager._plugin_commands[clean] = {
            "handler": handler,
            "description": description or "Plugin command",
            "plugin": self.manifest.name,
        }
        logger.debug("Plugin %s registered command: /%s", self.manifest.name, clean)

    # -- tool dispatch -------------------------------------------------------

    def dispatch_tool(self, tool_name: str, args: dict, **kwargs) -> str:
        """Dispatch a tool call through the registry, with parent agent context.

        This is the public interface for plugin slash commands that need to call
        tools like ``delegate_task`` without reaching into framework internals.
        The parent agent (if available) is resolved automatically — plugins never
        need to access the agent directly.

        Args:
            tool_name: Registry name of the tool (e.g. ``"delegate_task"``).
            args: Tool arguments dict (same as what the model would pass).
            **kwargs: Extra keyword args forwarded to the registry dispatch.

        Returns:
            JSON string from the tool handler (same format as model tool calls).
        """
        from tools.registry import registry

        # Wire up parent agent context when available (CLI mode).
        # In gateway mode _cli_ref is None — tools degrade gracefully
        # (workspace hints fall back to TERMINAL_CWD, no spinner).
        if "parent_agent" not in kwargs:
            cli = self._manager._cli_ref
            agent = getattr(cli, "agent", None) if cli else None
            if agent is not None:
                kwargs["parent_agent"] = agent

        return registry.dispatch(tool_name, args, **kwargs)

    # -- context engine registration -----------------------------------------

    def register_context_engine(self, engine) -> None:
        """Register a context engine to replace the built-in ContextCompressor.

        Only one context engine plugin is allowed. If a second plugin tries
        to register one, it is rejected with a warning.

        The engine must be an instance of ``agent.context_engine.ContextEngine``.
        """
        if self._manager._context_engine is not None:
            logger.warning(
                "Plugin '%s' tried to register a context engine, but one is "
                "already registered. Only one context engine plugin is allowed.",
                self.manifest.name,
            )
            return
        # Defer the import to avoid circular deps at module level
        from agent.context_engine import ContextEngine
        if not isinstance(engine, ContextEngine):
            logger.warning(
                "Plugin '%s' tried to register a context engine that does not "
                "inherit from ContextEngine. Ignoring.",
                self.manifest.name,
            )
            return
        self._manager._context_engine = engine
        logger.info(
            "Plugin '%s' registered context engine: %s",
            self.manifest.name, engine.name,
        )

    # -- hook registration --------------------------------------------------

    def register_hook(self, hook_name: str, callback: Callable) -> None:
        """Register a lifecycle hook callback.

        Unknown hook names produce a warning but are still stored so
        forward-compatible plugins don't break.
        """
        if hook_name not in VALID_HOOKS:
            logger.warning(
                "Plugin '%s' registered unknown hook '%s' "
                "(valid: %s)",
                self.manifest.name,
                hook_name,
                ", ".join(sorted(VALID_HOOKS)),
            )
        self._manager._hooks.setdefault(hook_name, []).append(callback)
        logger.debug("Plugin %s registered hook: %s", self.manifest.name, hook_name)

    # -- skill registration -------------------------------------------------

    def register_skill(
        self,
        name: str,
        path: Path,
        description: str = "",
    ) -> None:
        """Register a read-only skill provided by this plugin.

        The skill becomes resolvable as ``'<plugin_name>:<name>'`` via
        ``skill_view()``.  It does **not** enter the flat
        ``~/.hermes/skills/`` tree and is **not** listed in the system
        prompt's ``<available_skills>`` index — plugin skills are
        opt-in explicit loads only.

        Raises:
            ValueError: if *name* contains ``':'`` or invalid characters.
            FileNotFoundError: if *path* does not exist.
        """
        from agent.skill_utils import _NAMESPACE_RE

        if ":" in name:
            raise ValueError(
                f"Skill name '{name}' must not contain ':' "
                f"(the namespace is derived from the plugin name "
                f"'{self.manifest.name}' automatically)."
            )
        if not name or not _NAMESPACE_RE.match(name):
            raise ValueError(
                f"Invalid skill name '{name}'. Must match [a-zA-Z0-9_-]+."
            )
        if not path.exists():
            raise FileNotFoundError(f"SKILL.md not found at {path}")

        qualified = f"{self.manifest.name}:{name}"
        self._manager._plugin_skills[qualified] = {
            "path": path,
            "plugin": self.manifest.name,
            "bare_name": name,
            "description": description,
        }
        logger.debug(
            "Plugin %s registered skill: %s",
            self.manifest.name, qualified,
        )


# ---------------------------------------------------------------------------
# PluginManager
# ---------------------------------------------------------------------------

class PluginManager:
    """Central manager that discovers, loads, and invokes plugins."""

    def __init__(self) -> None:
        self._plugins: Dict[str, LoadedPlugin] = {}
        self._hooks: Dict[str, List[Callable]] = {}
        self._plugin_tool_names: Set[str] = set()
        self._cli_commands: Dict[str, dict] = {}
        self._context_engine = None  # Set by a plugin via register_context_engine()
        self._plugin_commands: Dict[str, dict] = {}  # Slash commands registered by plugins
        self._discovered: bool = False
        self._cli_ref = None  # Set by CLI after plugin discovery
        # Plugin skill registry: qualified name → metadata dict.
        self._plugin_skills: Dict[str, Dict[str, Any]] = {}

    # -----------------------------------------------------------------------
    # Public
    # -----------------------------------------------------------------------

    def discover_and_load(self) -> None:
        """Scan all plugin sources and load each plugin found."""
        if self._discovered:
            return
        self._discovered = True

        manifests: List[PluginManifest] = []

        # 1. User plugins (~/.hermes/plugins/)
        user_dir = get_hermes_home() / "plugins"
        manifests.extend(self._scan_directory(user_dir, source="user"))

        # 2. Project plugins (./.hermes/plugins/)
        if _env_enabled("HERMES_ENABLE_PROJECT_PLUGINS"):
            project_dir = Path.cwd() / ".hermes" / "plugins"
            manifests.extend(self._scan_directory(project_dir, source="project"))

        # 3. Pip / entry-point plugins
        manifests.extend(self._scan_entry_points())

        # Load each manifest (skip user-disabled plugins)
        disabled = _get_disabled_plugins()
        for manifest in manifests:
            if manifest.name in disabled:
                loaded = LoadedPlugin(manifest=manifest, enabled=False)
                loaded.error = "disabled via config"
                self._plugins[manifest.name] = loaded
                logger.debug("Skipping disabled plugin '%s'", manifest.name)
                continue
            self._load_plugin(manifest)

        if manifests:
            logger.info(
                "Plugin discovery complete: %d found, %d enabled",
                len(self._plugins),
                sum(1 for p in self._plugins.values() if p.enabled),
            )

    # -----------------------------------------------------------------------
    # Directory scanning
    # -----------------------------------------------------------------------

    def _scan_directory(self, path: Path, source: str) -> List[PluginManifest]:
        """Read ``plugin.yaml`` manifests from subdirectories of *path*."""
        manifests: List[PluginManifest] = []
        if not path.is_dir():
            return manifests

        for child in sorted(path.iterdir()):
            if not child.is_dir():
                continue
            manifest_file = child / "plugin.yaml"
            if not manifest_file.exists():
                manifest_file = child / "plugin.yml"
            if not manifest_file.exists():
                logger.debug("Skipping %s (no plugin.yaml)", child)
                continue

            try:
                if yaml is None:
                    logger.warning("PyYAML not installed – cannot load %s", manifest_file)
                    continue
                data = yaml.safe_load(manifest_file.read_text()) or {}
                manifest = PluginManifest(
                    name=data.get("name", child.name),
                    version=str(data.get("version", "")),
                    description=data.get("description", ""),
                    author=data.get("author", ""),
                    requires_env=data.get("requires_env", []),
                    provides_tools=data.get("provides_tools", []),
                    provides_hooks=data.get("provides_hooks", []),
                    source=source,
                    path=str(child),
                )
                manifests.append(manifest)
            except Exception as exc:
                logger.warning("Failed to parse %s: %s", manifest_file, exc)

        return manifests

    # -----------------------------------------------------------------------
    # Entry-point scanning
    # -----------------------------------------------------------------------

    def _scan_entry_points(self) -> List[PluginManifest]:
        """Check ``importlib.metadata`` for pip-installed plugins."""
        manifests: List[PluginManifest] = []
        try:
            eps = importlib.metadata.entry_points()
            # Python 3.12+ returns a SelectableGroups; earlier returns dict
            if hasattr(eps, "select"):
                group_eps = eps.select(group=ENTRY_POINTS_GROUP)
            elif isinstance(eps, dict):
                group_eps = eps.get(ENTRY_POINTS_GROUP, [])
            else:
                group_eps = [ep for ep in eps if ep.group == ENTRY_POINTS_GROUP]

            for ep in group_eps:
                manifest = PluginManifest(
                    name=ep.name,
                    source="entrypoint",
                    path=ep.value,
                )
                manifests.append(manifest)
        except Exception as exc:
            logger.debug("Entry-point scan failed: %s", exc)

        return manifests

    # -----------------------------------------------------------------------
    # Loading
    # -----------------------------------------------------------------------

    def _load_plugin(self, manifest: PluginManifest) -> None:
        """Import a plugin module and call its ``register(ctx)`` function."""
        loaded = LoadedPlugin(manifest=manifest)

        try:
            if manifest.source in ("user", "project"):
                module = self._load_directory_module(manifest)
            else:
                module = self._load_entrypoint_module(manifest)

            loaded.module = module

            # Call register()
            register_fn = getattr(module, "register", None)
            if register_fn is None:
                loaded.error = "no register() function"
                logger.warning("Plugin '%s' has no register() function", manifest.name)
            else:
                ctx = PluginContext(manifest, self)
                register_fn(ctx)
                loaded.tools_registered = [
                    t for t in self._plugin_tool_names
                    if t not in {
                        n
                        for name, p in self._plugins.items()
                        for n in p.tools_registered
                    }
                ]
                loaded.hooks_registered = list(
                    {
                        h
                        for h, cbs in self._hooks.items()
                        if cbs  # non-empty
                    }
                    - {
                        h
                        for name, p in self._plugins.items()
                        for h in p.hooks_registered
                    }
                )
                loaded.commands_registered = [
                    c for c in self._plugin_commands
                    if self._plugin_commands[c].get("plugin") == manifest.name
                ]
                loaded.enabled = True

        except Exception as exc:
            loaded.error = str(exc)
            logger.warning("Failed to load plugin '%s': %s", manifest.name, exc)

        self._plugins[manifest.name] = loaded

    def _load_directory_module(self, manifest: PluginManifest) -> types.ModuleType:
        """Import a directory-based plugin as ``hermes_plugins.<name>``."""
        plugin_dir = Path(manifest.path)  # type: ignore[arg-type]
        init_file = plugin_dir / "__init__.py"
        if not init_file.exists():
            raise FileNotFoundError(f"No __init__.py in {plugin_dir}")

        # Ensure the namespace parent package exists
        if _NS_PARENT not in sys.modules:
            ns_pkg = types.ModuleType(_NS_PARENT)
            ns_pkg.__path__ = []  # type: ignore[attr-defined]
            ns_pkg.__package__ = _NS_PARENT
            sys.modules[_NS_PARENT] = ns_pkg

        module_name = f"{_NS_PARENT}.{manifest.name.replace('-', '_')}"
        spec = importlib.util.spec_from_file_location(
            module_name,
            init_file,
            submodule_search_locations=[str(plugin_dir)],
        )
        if spec is None or spec.loader is None:
            raise ImportError(f"Cannot create module spec for {init_file}")

        module = importlib.util.module_from_spec(spec)
        module.__package__ = module_name
        module.__path__ = [str(plugin_dir)]  # type: ignore[attr-defined]
        sys.modules[module_name] = module
        spec.loader.exec_module(module)
        return module

    def _load_entrypoint_module(self, manifest: PluginManifest) -> types.ModuleType:
        """Load a pip-installed plugin via its entry-point reference."""
        eps = importlib.metadata.entry_points()
        if hasattr(eps, "select"):
            group_eps = eps.select(group=ENTRY_POINTS_GROUP)
        elif isinstance(eps, dict):
            group_eps = eps.get(ENTRY_POINTS_GROUP, [])
        else:
            group_eps = [ep for ep in eps if ep.group == ENTRY_POINTS_GROUP]

        for ep in group_eps:
            if ep.name == manifest.name:
                return ep.load()

        raise ImportError(
            f"Entry point '{manifest.name}' not found in group '{ENTRY_POINTS_GROUP}'"
        )

    # -----------------------------------------------------------------------
    # Hook invocation
    # -----------------------------------------------------------------------

    def invoke_hook(self, hook_name: str, **kwargs: Any) -> List[Any]:
        """Call all registered callbacks for *hook_name*.

        Each callback is wrapped in its own try/except so a misbehaving
        plugin cannot break the core agent loop.

        Returns a list of non-``None`` return values from callbacks.

        For ``pre_llm_call``, callbacks may return a dict describing
        context to inject into the current turn's user message::

            {"context": "recalled text..."}
            "recalled text..."          # plain string, equivalent

        Context is ALWAYS injected into the user message, never the
        system prompt.  This preserves the prompt cache prefix — the
        system prompt stays identical across turns so cached tokens
        are reused.  All injected context is ephemeral — never
        persisted to session DB.
        """
        callbacks = self._hooks.get(hook_name, [])
        results: List[Any] = []
        for cb in callbacks:
            try:
                ret = cb(**kwargs)
                if ret is not None:
                    results.append(ret)
            except Exception as exc:
                logger.warning(
                    "Hook '%s' callback %s raised: %s",
                    hook_name,
                    getattr(cb, "__name__", repr(cb)),
                    exc,
                )
        return results

    # -----------------------------------------------------------------------
    # Introspection
    # -----------------------------------------------------------------------

    def list_plugins(self) -> List[Dict[str, Any]]:
        """Return a list of info dicts for all discovered plugins."""
        result: List[Dict[str, Any]] = []
        for name, loaded in sorted(self._plugins.items()):
            result.append(
                {
                    "name": name,
                    "version": loaded.manifest.version,
                    "description": loaded.manifest.description,
                    "source": loaded.manifest.source,
                    "enabled": loaded.enabled,
                    "tools": len(loaded.tools_registered),
                    "hooks": len(loaded.hooks_registered),
                    "commands": len(loaded.commands_registered),
                    "error": loaded.error,
                }
            )
        return result

    # -----------------------------------------------------------------------
    # Plugin skill lookups
    # -----------------------------------------------------------------------

    def find_plugin_skill(self, qualified_name: str) -> Optional[Path]:
        """Return the ``Path`` to a plugin skill's SKILL.md, or ``None``."""
        entry = self._plugin_skills.get(qualified_name)
        return entry["path"] if entry else None

    def list_plugin_skills(self, plugin_name: str) -> List[str]:
        """Return sorted bare names of all skills registered by *plugin_name*."""
        prefix = f"{plugin_name}:"
        return sorted(
            e["bare_name"]
            for qn, e in self._plugin_skills.items()
            if qn.startswith(prefix)
        )

    def remove_plugin_skill(self, qualified_name: str) -> None:
        """Remove a stale registry entry (silently ignores missing keys)."""
        self._plugin_skills.pop(qualified_name, None)


# ---------------------------------------------------------------------------
# Module-level singleton & convenience functions
# ---------------------------------------------------------------------------

_plugin_manager: Optional[PluginManager] = None


def get_plugin_manager() -> PluginManager:
    """Return (and lazily create) the global PluginManager singleton."""
    global _plugin_manager
    if _plugin_manager is None:
        _plugin_manager = PluginManager()
    return _plugin_manager


def discover_plugins() -> None:
    """Discover and load all plugins (idempotent)."""
    get_plugin_manager().discover_and_load()


def invoke_hook(hook_name: str, **kwargs: Any) -> List[Any]:
    """Invoke a lifecycle hook on all loaded plugins.

    Returns a list of non-``None`` return values from plugin callbacks.
    """
    return get_plugin_manager().invoke_hook(hook_name, **kwargs)



def get_pre_tool_call_block_message(
    tool_name: str,
    args: Optional[Dict[str, Any]],
    task_id: str = "",
    session_id: str = "",
    tool_call_id: str = "",
) -> Optional[str]:
    """Check ``pre_tool_call`` hooks for a blocking directive.

    Plugins that need to enforce policy (rate limiting, security
    restrictions, approval workflows) can return::

        {"action": "block", "message": "Reason the tool was blocked"}

    from their ``pre_tool_call`` callback.  The first valid block
    directive wins.  Invalid or irrelevant hook return values are
    silently ignored so existing observer-only hooks are unaffected.
    """
    hook_results = invoke_hook(
        "pre_tool_call",
        tool_name=tool_name,
        args=args if isinstance(args, dict) else {},
        task_id=task_id,
        session_id=session_id,
        tool_call_id=tool_call_id,
    )

    for result in hook_results:
        if not isinstance(result, dict):
            continue
        if result.get("action") != "block":
            continue
        message = result.get("message")
        if isinstance(message, str) and message:
            return message

    return None


def get_plugin_context_engine():
    """Return the plugin-registered context engine, or None."""
    return get_plugin_manager()._context_engine


def get_plugin_command_handler(name: str) -> Optional[Callable]:
    """Return the handler for a plugin-registered slash command, or ``None``."""
    entry = get_plugin_manager()._plugin_commands.get(name)
    return entry["handler"] if entry else None


def get_plugin_commands() -> Dict[str, dict]:
    """Return the full plugin commands dict (name → {handler, description, plugin}).

    Safe to call before discovery — returns an empty dict if no plugins loaded.
    """
    return get_plugin_manager()._plugin_commands


def get_plugin_toolsets() -> List[tuple]:
    """Return plugin toolsets as ``(key, label, description)`` tuples.

    Used by the ``hermes tools`` TUI so plugin-provided toolsets appear
    alongside the built-in ones and can be toggled on/off per platform.
    """
    manager = get_plugin_manager()
    if not manager._plugin_tool_names:
        return []

    try:
        from tools.registry import registry
    except Exception:
        return []

    # Group plugin tool names by their toolset
    toolset_tools: Dict[str, List[str]] = {}
    toolset_plugin: Dict[str, LoadedPlugin] = {}
    for tool_name in manager._plugin_tool_names:
        entry = registry.get_entry(tool_name)
        if not entry:
            continue
        ts = entry.toolset
        toolset_tools.setdefault(ts, []).append(entry.name)

    # Map toolsets back to the plugin that registered them
    for _name, loaded in manager._plugins.items():
        for tool_name in loaded.tools_registered:
            entry = registry.get_entry(tool_name)
            if entry and entry.toolset in toolset_tools:
                toolset_plugin.setdefault(entry.toolset, loaded)

    result = []
    for ts_key in sorted(toolset_tools):
        plugin = toolset_plugin.get(ts_key)
        label = f"🔌 {ts_key.replace('_', ' ').title()}"
        if plugin and plugin.manifest.description:
            desc = plugin.manifest.description
        else:
            desc = ", ".join(sorted(toolset_tools[ts_key]))
        result.append((ts_key, label, desc))

    return result