feat(mcp): scaffold three project context tools

mcp_servers/project_context/tools/knowledge_search.py

@@ -0,0 +1,58 @@
+"""Member B work package: search_project_knowledge."""
+
+# ruff: noqa: UP045 -- Optional keeps Pydantic model evaluation compatible with Python 3.9.
+
+from __future__ import annotations
+
+from typing import Any, Literal, Optional
+
+from pydantic import Field
+
+from ..foundation import ContractModel, SourceCitation, ToolTemplate
+
+
+class KnowledgeSearchInput(ContractModel):
+    project_id: str = Field(min_length=1, max_length=128)
+    query: str = Field(min_length=2, max_length=1000)
+    detail: Literal["summary", "standard", "full"] = "standard"
+    top_k: int = Field(default=5, ge=1, le=20)
+    language: Optional[Literal["en", "ja", "vi"]] = None
+    cursor: Optional[str] = Field(default=None, max_length=2048)
+
+
+class KnowledgeItem(ContractModel):
+    document_id: str
+    chunk_id: str
+    title: str
+    excerpt: str
+    score: float = Field(ge=0, le=1)
+    source: SourceCitation
+
+
+class KnowledgeSearchOutput(ContractModel):
+    correlation_id: str
+    project_id: str
+    query: str
+    items: tuple[KnowledgeItem, ...]
+    truncated: bool
+    returned: int = Field(ge=0)
+    remaining: int = Field(ge=0)
+    next_cursor: Optional[str] = None
+
+
+def _handle(arguments: ContractModel, provider: Any) -> dict[str, Any]:
+    request = KnowledgeSearchInput.model_validate(arguments)
+    return provider.search_knowledge(**request.model_dump())
+
+
+TOOL = ToolTemplate(
+    name="search_project_knowledge",
+    description=(
+        "Searches approved knowledge for one authorized project and returns ranked excerpts with "
+        "pinned citations. Use for requirements, design notes, or runbooks when no exact issue is "
+        "known. Do not use for issue details or Git change review."
+    ),
+    input_model=KnowledgeSearchInput,
+    output_model=KnowledgeSearchOutput,
+    handler=_handle,
+)