Teknium
329 lines
17 KiB
Python
329 lines
17 KiB
Python
"""Registering a connected (or schema-cached) MCP server's tools into the tool registry:
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include/exclude filtering, trust-tier metadata capture, utility-tool selection,
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name-collision resolution and the schema-cache write-through. Both entry points
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(``_register_server_tools`` live, ``_register_from_cache_sync`` lazy) build ``_Candidate``
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records and feed the single ``_register_candidates`` loop."""
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import logging
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from dataclasses import dataclass
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from typing import TYPE_CHECKING, Any, Callable, Dict, Iterable, List, Optional
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from tools.mcp_tool_common import _parse_boolish, _core, _resolve_tool_timeout
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from tools.mcp_tool_handlers import (
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_make_check_fn, _make_get_prompt_handler, _make_list_prompts_handler,
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_make_list_resources_handler, _make_read_resource_handler)
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from tools.mcp_tool_schema import (
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_UTILITY_CAPABILITY_ATTRS, _build_utility_schemas, _normalize_name_filter, matches_name_filter)
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if TYPE_CHECKING: # pragma: no cover
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from tools.mcp_tool import MCPServerTask
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logger = logging.getLogger("tools.mcp_tool")
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_UTILITY_ORIGIN_PREFIX = "generated utility "
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# Utility tool key -> handler factory; each takes (server_name, tool_timeout).
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_UTILITY_HANDLER_FACTORIES = {
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"list_resources": _make_list_resources_handler, "read_resource": _make_read_resource_handler,
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"list_prompts": _make_list_prompts_handler, "get_prompt": _make_get_prompt_handler}
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def _normalize_server_trust(value: Any) -> str:
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"""Config ``trust`` -> tier. None -> ``full`` (backward-compatible default); an
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unrecognized string -> ``untrusted`` so a misspelled tier fails closed."""
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if value is None:
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return _core._TRUST_FULL
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text = str(value).strip().lower()
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if text in (_core._TRUST_FULL, _core._TRUST_UNTRUSTED):
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return text
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logger.warning("MCP trust: unrecognized trust value %r — treating as 'untrusted' (valid values: full, untrusted)",
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value)
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return _core._TRUST_UNTRUSTED
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def _annotation_read_only_hint(mcp_tool: Any) -> bool:
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"""True only when annotations (SDK object or schema-cache dict) carry ``readOnlyHint is
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True``; unknown metadata means write-capable."""
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annotations = getattr(mcp_tool, "annotations", None)
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if isinstance(annotations, dict):
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return annotations.get("readOnlyHint") is True
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return getattr(annotations, "readOnlyHint", None) is True
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def _record_tool_trust_metadata(server_name: str, config: dict, tools: List[Any]) -> None:
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"""Capture per-server trust and per-tool readOnlyHint at discovery — the security
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boundary: the call-time gate classifies from data we control, never re-read
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server-supplied state."""
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with _core._lock:
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_core._server_trust_levels[server_name] = _normalize_server_trust((config or {}).get("trust"))
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hints = _core._tool_read_only_hints.setdefault(server_name, {})
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for tool in tools:
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name = getattr(tool, "name", None)
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if name:
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hints[name] = _annotation_read_only_hint(tool)
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def _track_mcp_tool_server(tool_name: str, server_name: str) -> None:
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"""Remember the exact raw MCP server that registered *tool_name*."""
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with _core._lock:
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_core._mcp_tool_server_names[tool_name] = server_name
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def _forget_mcp_tool_server(tool_name: str) -> None:
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"""Forget MCP server provenance for a deregistered tool."""
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with _core._lock:
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_core._mcp_tool_server_names.pop(tool_name, None)
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def _select_utility_schemas(server_name: str, server: "MCPServerTask", config: dict) -> List[dict]:
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"""Utility schemas allowed by config (``tools.resources``/``tools.prompts``) and advertised
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capabilities. ``initialize_result.capabilities`` is the truth (sub-object non-None iff the
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family is served); without it fall back to the legacy session-method check, which never
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filters anything since ClientSession defines all four methods."""
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tools_filter = config.get("tools") or {}
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enabled = {f: _parse_boolish(tools_filter.get(f), default=True) for f in ("resources", "prompts")}
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init_result = getattr(server, "initialize_result", None)
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advertised = getattr(init_result, "capabilities", None) if init_result is not None else None
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def _skip_reason(handler_key: str) -> Optional[str]:
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family = _UTILITY_CAPABILITY_ATTRS[handler_key]
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if not enabled[family]:
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return f"{family} disabled"
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if advertised is not None:
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if getattr(advertised, family, None) is None:
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return f"server does not advertise '{family}' capability"
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return None
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# Legacy gate (no initialize_result): the ClientSession method shares the handler key.
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return None if hasattr(server.session, handler_key) else f"session lacks {handler_key}"
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selected: List[dict] = []
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for entry in _build_utility_schemas(server_name):
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reason = _skip_reason(entry["handler_key"])
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if reason:
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logger.debug("MCP server '%s': skipping utility '%s' (%s)", server_name, entry["handler_key"], reason)
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else:
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selected.append(entry)
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return selected
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def _existing_tool_names() -> List[str]:
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"""Tool names for all currently connected servers plus lazy (cache-registered) servers,
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whose tools live only in the registry."""
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names: List[str] = []
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for server in _core._servers.values():
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names.extend(server._registered_tool_names if hasattr(server, "_registered_tool_names")
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else (_core._convert_mcp_schema(server.name, t)["name"] for t in server._tools))
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with _core._lock:
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names.extend(n for sname, tool_names in _core._lazy_server_tool_names.items()
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if sname not in _core._servers for n in tool_names)
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return names
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def _make_tool_filter(name: str, config: dict) -> Callable[[str], bool]:
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"""Include/exclude predicate for a server's tool names: ``tools.include`` is a whitelist
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(``[]`` = register nothing), ``tools.exclude`` a blacklist; entries are exact names or
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fnmatch globs; include wins over exclude."""
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tools_filter = config.get("tools") or {}
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include_raw = tools_filter.get("include")
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include_set = _normalize_name_filter(include_raw, f"mcp_servers.{name}.tools.include")
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exclude_set = _normalize_name_filter(tools_filter.get("exclude"), f"mcp_servers.{name}.tools.exclude")
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if isinstance(include_raw, (str, list, tuple, set)):
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return lambda tool_name: matches_name_filter(tool_name, include_set)
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return lambda tool_name: not (exclude_set and matches_name_filter(tool_name, exclude_set))
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class _CachedMCPTool:
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"""Stand-in for MCP Tool objects loaded from the schema cache. Missing or non-dict
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``annotations`` (older cache files) fail closed to write-capable."""
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__slots__ = ("name", "description", "inputSchema", "annotations")
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def __init__(self, name: str, description: str, inputSchema: dict, annotations: Optional[dict] = None):
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self.name = name
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self.description = description
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self.inputSchema = inputSchema or {}
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self.annotations = annotations if isinstance(annotations, dict) else None
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@classmethod
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def from_cache_dicts(cls, raws: Iterable[Any]) -> List["_CachedMCPTool"]:
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"""Cached rows -> stand-ins; rows that are not dicts or lack a name are dropped."""
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return [cls(raw["name"], raw.get("description") or "",
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raw["inputSchema"] if isinstance(raw.get("inputSchema"), dict) else {}, raw.get("annotations"))
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for raw in raws if isinstance(raw, dict) and raw.get("name")]
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@dataclass
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class _Candidate:
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"""One registration attempt: a native tool or a generated utility. ``origin`` is the
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provenance text used in collision diagnostics."""
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registry_name: str
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origin: str
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schema: dict
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handler: Callable
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@property
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def is_utility(self) -> bool:
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return self.origin.startswith(_UTILITY_ORIGIN_PREFIX)
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def _tool_candidates(name: str, tools: Iterable[Any], should_register: Callable[[str], bool],
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tool_timeout) -> List[_Candidate]:
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"""Native tools (live SDK objects or ``_CachedMCPTool``) -> candidates. The injection scan
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runs on BOTH paths: the cache file is user-writable JSON."""
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out: List[_Candidate] = []
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for t in tools:
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if not should_register(t.name):
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logger.debug("MCP server '%s': skipping tool '%s' (filtered by config)", name, t.name)
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continue
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_core._scan_mcp_description(name, t.name, t.description or "")
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schema = _core._convert_mcp_schema(name, t)
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handler = _core._make_tool_handler(name, t.name, tool_timeout)
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out.append(_Candidate(schema["name"], f"tool {t.name!r}", schema, handler))
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return out
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def _utility_candidates(name: str, entries: Iterable[Any], tool_timeout) -> List[_Candidate]:
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"""``{schema, handler_key}`` rows (live selection or cache) -> candidates; malformed rows dropped."""
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out: List[_Candidate] = []
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for raw in entries:
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schema, key = (raw.get("schema"), raw.get("handler_key")) if isinstance(raw, dict) else (None, None)
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if isinstance(schema, dict) and key in _UTILITY_HANDLER_FACTORIES and schema.get("name"):
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handler = _UTILITY_HANDLER_FACTORIES[key](name, tool_timeout)
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out.append(_Candidate(schema["name"], f"{_UTILITY_ORIGIN_PREFIX}{key!r}", schema, handler))
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return out
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def _resolve_name_collisions(name: str, candidates: List[_Candidate]) -> List[_Candidate]:
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"""Preflight name collisions: exact duplicates dropped silently; a utility normalizing onto
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a native tool's name is shadowed (native wins); any other multi-origin collision skips every
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colliding entry (fail closed). Returns survivors in order."""
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unique: List[_Candidate] = []
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seen: set[tuple[str, str]] = set()
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origins_by_name: Dict[str, set[str]] = {}
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for c in candidates:
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if (c.registry_name, c.origin) in seen:
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logger.debug("MCP server '%s': duplicate registration candidate %s for '%s'; keeping one",
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name, c.origin, c.registry_name)
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continue
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seen.add((c.registry_name, c.origin))
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unique.append(c)
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origins_by_name.setdefault(c.registry_name, set()).add(c.origin)
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ambiguous: Dict[str, List[str]] = {}
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shadowed: set[tuple[str, str]] = set()
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for registry_name, origins in origins_by_name.items():
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if len(origins) <= 1:
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continue
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utility_origins = sorted(o for o in origins if o.startswith(_UTILITY_ORIGIN_PREFIX))
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native_origins = sorted(origins - set(utility_origins))
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if len(native_origins) == 1 and utility_origins:
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shadowed.update((registry_name, o) for o in utility_origins)
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logger.info(
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"MCP server '%s': generated utility %s normalizes onto server-native %s — keeping the native tool "
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"and dropping the utility (the utility only applies when the server has no such tool of its own)",
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name, ", ".join(utility_origins), native_origins[0])
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continue
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ambiguous[registry_name] = sorted(origins)
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for registry_name, origins in sorted(ambiguous.items()):
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logger.error("MCP server '%s': name normalization collision for '%s' from %s; skipping every colliding "
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"entry instead of choosing an arbitrary handler", name, registry_name, ", ".join(origins))
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return [c for c in unique if c.registry_name not in ambiguous and (c.registry_name, c.origin) not in shadowed]
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def _log_foreign_owner(name: str, c: _Candidate, existing_toolset: str, lazy: bool) -> None:
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"""Diagnostics for a name already owned by another toolset (skipped to preserve the owner)."""
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if lazy:
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if not c.is_utility:
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logger.warning("MCP server '%s' (lazy): cached tool '%s' collides with toolset '%s' — skipping",
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name, c.registry_name, existing_toolset)
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return
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if existing_toolset.startswith("mcp-"):
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logger.error("MCP server '%s': %s normalizes to '%s', already owned by MCP toolset '%s' — skipping to "
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"preserve the existing owner", name, c.origin, c.registry_name, existing_toolset)
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else:
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logger.warning("MCP server '%s': %s (→ '%s') collides with built-in tool in toolset '%s' — skipping to "
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"preserve built-in", name, c.origin, c.registry_name, existing_toolset)
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def _register_candidates(name: str, candidates: List[_Candidate], *, check_fn: Callable,
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scope: Callable[[], Optional[str]], lazy: bool) -> List[str]:
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"""Register candidates under toolset ``mcp-{name}``; returns the names that landed. The
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ownership pre-check is advisory (servers connect in parallel): ``registry.register()`` is
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the atomic gate and its verdict is re-read after every call."""
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from tools.registry import registry
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toolset_name = f"mcp-{name}"
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registered: List[str] = []
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for c in candidates:
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existing_toolset = registry.get_toolset_for_tool(c.registry_name)
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if existing_toolset and existing_toolset != toolset_name:
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_log_foreign_owner(name, c, existing_toolset, lazy)
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continue
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registry.register(
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name=c.registry_name, toolset=toolset_name, schema=c.schema, handler=c.handler, check_fn=check_fn,
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is_async=False, description=c.schema.get("description") or "", scope=scope())
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if registry.get_toolset_for_tool(c.registry_name) != toolset_name:
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if not lazy:
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logger.error("MCP server '%s': registration of %s as '%s' was rejected by the registry; "
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"skipping provenance/count updates", name, c.origin, c.registry_name)
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continue
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_core._track_mcp_tool_server(c.registry_name, name)
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registered.append(c.registry_name)
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if registered:
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registry.register_toolset_alias(name, toolset_name)
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return registered
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def _write_schema_cache(name: str, server: "MCPServerTask", config: dict, should_register) -> None:
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"""Write-through: persist the manifest so the next startup can register this server
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lazily without spawning it. Never raises."""
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try:
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from tools.mcp_schema_cache import config_fingerprint, write_cache_entry
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tools_payload = [{
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"name": t.name, "description": t.description or "",
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"inputSchema": t.inputSchema if isinstance(getattr(t, "inputSchema", None), dict) else {},
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# Persisted so the lazy path trust-gates identically next startup.
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"annotations": {"readOnlyHint": _annotation_read_only_hint(t)},
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} for t in server._tools if should_register(t.name)]
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utility_payload = [{"schema": e["schema"], "handler_key": e["handler_key"]}
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for e in _select_utility_schemas(name, server, config)]
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cache_meta = getattr(server, "_list_cache_meta", None) or {}
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write_cache_entry(name, config_fingerprint(config), tools=tools_payload, utility_tools=utility_payload,
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ttl_ms=cache_meta.get("ttl_ms"), cache_scope=cache_meta.get("cache_scope"))
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except Exception as exc:
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logger.debug("MCP schema cache write failed for '%s': %s", name, exc)
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def _register_server_tools(name: str, server: "MCPServerTask", config: dict) -> List[str]:
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"""Register a connected server's tools plus utilities (initial discovery and list_changed
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refresh); returns the names. Toolset aliases derive from the live registry, not
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``toolsets.TOOLSETS``; lossy normalization collisions (``read-file``/``read_file``) fail closed."""
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should_register = _make_tool_filter(name, config)
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_record_tool_trust_metadata(name, config, server._tools)
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candidates = _tool_candidates(name, server._tools, should_register, server.tool_timeout)
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candidates += _utility_candidates(name, _select_utility_schemas(name, server, config), server.tool_timeout)
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registered = _register_candidates(
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name, _resolve_name_collisions(name, candidates),
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check_fn=_make_check_fn(name), scope=lambda: _core._server_registry_scope(name), lazy=False)
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if registered:
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_write_schema_cache(name, server, config, should_register)
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return registered
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def _register_from_cache_sync(name: str, config: dict, entry: dict) -> List[str]:
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"""Lazy startup: register from a cached manifest with no child process (first real call goes
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through ``_ensure_lazy_server_connected``). Trust metadata is recorded first so the
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call-time gate is identical for live and cached registrations."""
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from tools.mcp_schema_cache import config_fingerprint, tools_from_cache_entry, utility_tools_from_cache_entry
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tool_timeout = _resolve_tool_timeout(config)
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cached_tools = _CachedMCPTool.from_cache_dicts(tools_from_cache_entry(entry))
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_record_tool_trust_metadata(name, config, cached_tools)
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candidates = _tool_candidates(name, cached_tools, _make_tool_filter(name, config), tool_timeout)
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candidates += _utility_candidates(name, utility_tools_from_cache_entry(entry), tool_timeout)
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registered = _register_candidates(
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name, candidates, check_fn=_make_check_fn(name), scope=_core._mcp_registry_scope, lazy=True)
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if registered:
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with _core._lock:
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_core._lazy_server_configs[name] = dict(config)
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_core._lazy_server_fingerprints[name] = config_fingerprint(config)
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_core._lazy_server_tool_names[name] = list(registered)
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logger.info("MCP server '%s' (lazy): registered %d tool(s) from schema cache", name, len(registered))
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return registered
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