feat(docs): add MCP artifact generation to manage_docs CLI

- Introduced `build_mcp` command to generate docs-only MCP artifacts
- Reuses existing MkDocs + mkdocstrings pipeline (no code introspection)
- Extracts `:::` mkdocstrings directives from generated Markdown
- Emits structured MCP output:
  - `mcp/index.json` (project metadata)
  - `mcp/nav.json` (page → module mapping)
  - `mcp/modules/*.json` (per-module references)
- Preserves all existing commands and behavior (`generate`, `build`, `serve`)
- Avoids source code exposure; MCP output is derived solely from documentation

This enables a clean docs → MCP → MCP server workflow suitable for AI IDE integration.

manage_docs.py

@@ -18,6 +18,7 @@ Usage:
     python manage_docs.py generate
     python manage_docs.py build
     python manage_docs.py serve
+    python manage_docs.py build_mcp
 
 Optional flags:
     --docs-dir PATH        Path to docs directory (default: ./docs)
@@ -27,7 +28,10 @@ Optional flags:
 from __future__ import annotations
 
 import argparse
+import json
+import re
 from pathlib import Path
+from typing import Iterable
 
 from mkdocs.commands import build as mkdocs_build
 from mkdocs.commands import serve as mkdocs_serve
@@ -38,7 +42,14 @@ PROJECT_ROOT = Path(__file__).resolve().parent
 DEFAULT_DOCS_DIR = PROJECT_ROOT / "docs"
 DEFAULT_PACKAGE_ROOT = "mail_intake"
 MKDOCS_YML = PROJECT_ROOT / "mkdocs.yml"
+DEFAULT_MCP_DIR = PROJECT_ROOT / "mcp"
 
+MKDOCSTRINGS_DIRECTIVE = re.compile(r"^:::\s+([a-zA-Z0-9_.]+)", re.MULTILINE)
+
+
+# -------------------------
+# Existing functionality
+# -------------------------
 
 def generate_docs_from_nav(
     project_root: Path,
@@ -116,10 +127,86 @@ def cmd_serve(_: argparse.Namespace) -> None:
         config_file=str(MKDOCS_YML)
     )
 
+
+# -------------------------
+# MCP generation
+# -------------------------
+
+def iter_markdown_files(docs_root: Path) -> Iterable[Path]:
+    yield from docs_root.rglob("*.md")
+
+
+def extract_modules(md_file: Path) -> list[str]:
+    content = md_file.read_text(encoding="utf-8")
+    return MKDOCSTRINGS_DIRECTIVE.findall(content)
+
+
+def cmd_build_mcp(args: argparse.Namespace) -> None:
+    docs_root = args.docs_dir
+    mcp_root = args.mcp_dir
+
+    modules_dir = mcp_root / "modules"
+    modules_dir.mkdir(parents=True, exist_ok=True)
+
+    nav = []
+    modules = []
+
+    for md in iter_markdown_files(docs_root):
+        rel = md.relative_to(docs_root)
+
+        module_refs = extract_modules(md)
+        if not module_refs:
+            continue
+
+        nav.append({
+            "page": str(rel),
+            "modules": module_refs,
+        })
+
+        for module in module_refs:
+            module_entry = {
+                "module": module,
+                "doc_page": str(rel),
+            }
+            modules.append(module_entry)
+
+            out = modules_dir / f"{module}.json"
+            out.parent.mkdir(parents=True, exist_ok=True)
+            out.write_text(
+                json.dumps(module_entry, indent=2),
+                encoding="utf-8",
+            )
+
+    mcp_root.mkdir(parents=True, exist_ok=True)
+
+    (mcp_root / "nav.json").write_text(
+        json.dumps(nav, indent=2),
+        encoding="utf-8",
+    )
+
+    (mcp_root / "index.json").write_text(
+        json.dumps(
+            {
+                "project": "Aetoskia Mail Intake",
+                "type": "docs-only",
+                "modules_count": len(modules),
+            },
+            indent=2,
+        ),
+        encoding="utf-8",
+    )
+
+    print(f"MCP artifacts written to: {mcp_root}")
+
+
+# -------------------------
+# CLI
+# -------------------------
+
 def main() -> None:
     parser = argparse.ArgumentParser(
         prog="manage_docs.py",
-        description="Manage MkDocs documentation for the project",
+        description="Manage MkDocs documentation and MCP exports for the project",
     )
 
     parser.add_argument(
@@ -128,12 +215,20 @@ def main() -> None:
         default=DEFAULT_DOCS_DIR,
         help="Path to the docs directory",
     )
+
     parser.add_argument(
         "--package-root",
         default=DEFAULT_PACKAGE_ROOT,
         help="Root Python package name",
     )
 
+    parser.add_argument(
+        "--mcp-dir",
+        type=Path,
+        default=DEFAULT_MCP_DIR,
+        help="Output directory for MCP artifacts",
+    )
+
     subparsers = parser.add_subparsers(dest="command", required=True)
 
     subparsers.add_parser(
@@ -151,6 +246,13 @@ def main() -> None:
         help="Serve the MkDocs site locally",
     ).set_defaults(func=cmd_serve)
 
+    subparsers.add_parser(
+        "build_mcp",
+        help="Generate MCP artifacts (docs-only)",
+    ).set_defaults(
+        func=cmd_build_mcp
+    )
+
     args = parser.parse_args()
     args.func(args)