mcp_server.py

#!/usr/bin/env python3
"""
Hermes WebUI MCP Server — exposes project and session management
as MCP tools for any MCP-compatible agent.

Option A rewrite (2026-05-08): imports api.models and api.profiles
directly from the webui codebase, using canonical helpers for
locking, profile scoping, index consistency, and validation.

    pip install mcp       # one-time setup
    python3 mcp_server.py # start via stdio

MCP config for Hermes Agent (add to config.yaml):
    mcp_servers:
      hermes-webui:
        command: /path/to/venv/bin/python3
        args: [/path/to/hermes-webui/mcp_server.py]
        env:
          HERMES_WEBUI_PASSWORD: your_password

Profile override (optional):
        args: [/path/to/hermes-webui/mcp_server.py, --profile, myprofile]

AI-authoring disclosure: this file was rewritten by MILO (Hermes Agent)
under human direction, per maintainer guidelines for #1616.
"""

import argparse
import json
import os
import re
import sys
import time
import uuid
from pathlib import Path

from mcp.server import Server
from mcp.server.stdio import stdio_server
from mcp.types import Tool, TextContent

# ── Ensure the repo root is on sys.path so api.* imports work ─────────────
_REPO_ROOT = Path(__file__).parent.resolve()
if str(_REPO_ROOT) not in sys.path:
    sys.path.insert(0, str(_REPO_ROOT))

# ── CLI: optional --profile override ──────────────────────────────────────
_profile_arg: str | None = None
_parser = argparse.ArgumentParser(add_help=False)
_parser.add_argument("--profile", type=str, default=None)
_args, _unknown = _parser.parse_known_args()
_profile_arg = _args.profile

# ── Import webui canonical modules (after path setup) ─────────────────────
import api.config as _cfg
from api.config import (
    STATE_DIR, SESSION_DIR, SESSION_INDEX_FILE, PROJECTS_FILE, HOME,
)
from api.models import load_projects, save_projects
from api.profiles import get_active_profile_name, _is_root_profile, _profiles_match

# ── Apply --profile override before any module uses get_active_profile_name
if _profile_arg is not None:
    import api.profiles as _profiles
    _profiles._active_profile = _profile_arg

# ── API auth state ─────────────────────────────────────────────────────────
# Mirror the env-var contract used by api/config.py:32-33 so a non-default
# WebUI port/host (e.g. when 8787 is held by another service on the host)
# Just Works without configuration drift between the WebUI process and MCP.
WEBUI_HOST = os.environ.get("HERMES_WEBUI_HOST", "127.0.0.1")
WEBUI_PORT = os.environ.get("HERMES_WEBUI_PORT", "8787")
WEBUI_URL = f"http://{WEBUI_HOST}:{WEBUI_PORT}"
_auth_cookie: str | None = None
_auth_expires: float = 0  # unix timestamp after which we re-auth

server = Server("hermes-webui")


# ═══════════════════════════════════════════════════════════════════════════
#  Helpers — filesystem (project CRUD via canonical api.models)
# ═══════════════════════════════════════════════════════════════════════════

def _active_profile() -> str:
    """Shorthand for the current profile name (--profile or auto-detected)."""
    return get_active_profile_name() or 'default'


def _validate_color(color: str | None) -> str | None:
    """Return an error string if color is invalid, else None."""
    if color is not None and not re.match(r"^#[0-9a-fA-F]{3,8}$", color):
        return "Invalid color format (use #RGB, #RRGGBB, or #RRGGBBAA)"
    return None


def _load_index() -> list:
    """Read the session index. Falls back to empty list on failure."""
    if not SESSION_INDEX_FILE.exists():
        return []
    try:
        return json.loads(SESSION_INDEX_FILE.read_text(encoding="utf-8"))
    except Exception:
        return []


def _session_compact(row: dict) -> dict:
    """Lightweight compact representation of a session index entry."""
    return {
        "session_id": row.get("session_id"),
        "title": row.get("title"),
        "project_id": row.get("project_id"),
        "workspace": row.get("workspace"),
        "model": row.get("model"),
        "message_count": row.get("message_count", 0),
        "source_tag": row.get("source_tag"),
        "is_cli_session": row.get("is_cli_session", False),
        "profile": row.get("profile"),
    }


# ═══════════════════════════════════════════════════════════════════════════
#  Helpers — HTTP API (for mutations that need cache sync)
# ═══════════════════════════════════════════════════════════════════════════

def _api_password() -> str | None:
    """Return the plaintext webui password from HERMES_WEBUI_PASSWORD, or None.

    settings.json stores only the bcrypt hash, which the login endpoint cannot
    accept — it calls verify_password(plaintext) against the stored hash. So
    there's no usable fallback when the env var is unset; the MCP simply runs
    in unauthenticated mode and any auth-protected mutation will fail clearly
    with the server's 401 instead of silently sending an unusable hash.
    """
    pw = os.environ.get("HERMES_WEBUI_PASSWORD", "").strip()
    return pw or None


def _api_auth() -> str | None:
    """Authenticate and return cookie value, or None if auth disabled/fails."""
    global _auth_cookie, _auth_expires

    pw = _api_password()
    if not pw:
        return None  # auth not enabled — API calls will fail anyway

    # Reuse cookie if still valid (25 days — server issues 30-day cookies)
    if _auth_cookie and time.time() < _auth_expires:
        return _auth_cookie

    import urllib.request

    try:
        req = urllib.request.Request(
            f"{WEBUI_URL}/api/auth/login",
            data=json.dumps({"password": pw}).encode(),
            headers={"Content-Type": "application/json"},
            method="POST",
        )
        resp = urllib.request.urlopen(req, timeout=5)
        cookie = resp.headers.get("Set-Cookie", "")
        if cookie:
            _auth_cookie = cookie.split(";")[0]  # "hermes_session=VALUE; ..."
            _auth_expires = time.time() + 25 * 86400  # 25 days
            return _auth_cookie
    except Exception:
        _auth_cookie = None
    return None


def _api_post(endpoint: str, body: dict) -> dict:
    """POST to webui API with auth cookie. Returns parsed JSON response."""
    import urllib.request
    import urllib.error

    cookie = _api_auth()
    headers = {"Content-Type": "application/json"}
    if cookie:
        headers["Cookie"] = cookie

    try:
        req = urllib.request.Request(
            f"{WEBUI_URL}{endpoint}",
            data=json.dumps(body).encode(),
            headers=headers,
            method="POST",
        )
        resp = urllib.request.urlopen(req, timeout=5)
        return json.loads(resp.read())
    except urllib.error.HTTPError as e:
        err_body = json.loads(e.read())
        return {"error": f"API {e.code}: {err_body.get('error', 'unknown')}"}
    except Exception as e:
        return {"error": f"API unreachable: {e}"}


# ═══════════════════════════════════════════════════════════════════════════
#  Tool handlers — read-only (filesystem, profile-aware)
# ═══════════════════════════════════════════════════════════════════════════

async def handle_list_projects(_arguments: dict) -> list[TextContent]:
    """List all projects with session counts, scoped to active profile."""
    projects = load_projects()
    active = _active_profile()
    index = _load_index()

    # Session counts per project (from index)
    counts: dict[str, int] = {}
    for s in index:
        pid = s.get("project_id")
        if pid:
            counts[pid] = counts.get(pid, 0) + 1

    result = []
    for p in projects:
        # Profile filter: legacy untagged rows are treated as 'default' by
        # _profiles_match, so non-root profiles correctly hide them.
        if not _profiles_match(p.get("profile"), active):
            continue
        entry = dict(p)
        entry["session_count"] = counts.get(p["project_id"], 0)
        result.append(entry)

    return [TextContent(type="text", text=json.dumps(result, ensure_ascii=False, indent=2))]


async def handle_list_sessions(arguments: dict) -> list[TextContent]:
    """List sessions, optionally filtered by project or unassigned status."""
    project_id = arguments.get("project_id")
    unassigned = arguments.get("unassigned", False)
    limit = max(1, min(500, arguments.get("limit", 50)))
    active = _active_profile()

    index = _load_index()
    sessions = [_session_compact(s) for s in index if s.get("session_id")]

    # Filter by profile: legacy untagged rows are treated as 'default' by
    # _profiles_match (canonical convention), so non-root profiles hide them.
    sessions = [s for s in sessions if _profiles_match(s.get("profile"), active)]

    if unassigned:
        sessions = [s for s in sessions if not s["project_id"]]
    elif project_id:
        sessions = [s for s in sessions if s["project_id"] == project_id]

    sessions = sessions[:limit]
    return [TextContent(type="text", text=json.dumps(sessions, ensure_ascii=False, indent=2))]


# ═══════════════════════════════════════════════════════════════════════════
#  Tool handlers — project CRUD (canonical helpers, profile-scoped)
# ═══════════════════════════════════════════════════════════════════════════

async def handle_create_project(arguments: dict) -> list[TextContent]:
    """Create a new project (profile-scoped, exact-match title collision)."""
    name = arguments.get("name", "").strip()[:128]
    if not name:
        return [TextContent(type="text", text=json.dumps(
            {"error": "name is required"}, ensure_ascii=False))]

    color = arguments.get("color")
    color_err = _validate_color(color)
    if color_err:
        return [TextContent(type="text", text=json.dumps(
            {"error": color_err}, ensure_ascii=False))]

    active = _active_profile()
    projects = load_projects()

    # Title collision: exact match (consistent with ensure_cron_project)
    if any(p.get("name") == name and _profiles_match(p.get("profile"), active)
           for p in projects):
        return [TextContent(type="text", text=json.dumps(
            {"error": f"Project '{name}' already exists"}, ensure_ascii=False))]

    proj = {
        "project_id": uuid.uuid4().hex[:12],
        "name": name,
        "color": color,
        "profile": active,
        "created_at": time.time(),
    }
    projects.append(proj)
    save_projects(projects)

    proj["session_count"] = 0
    return [TextContent(type="text", text=json.dumps(proj, ensure_ascii=False, indent=2))]


async def handle_rename_project(arguments: dict) -> list[TextContent]:
    """Rename a project and optionally change its color (profile-checked)."""
    project_id = arguments.get("project_id")
    name = arguments.get("name", "").strip()[:128]
    if not project_id or not name:
        return [TextContent(type="text", text=json.dumps(
            {"error": "project_id and name are required"}, ensure_ascii=False))]

    color = arguments.get("color")
    color_err = _validate_color(color)
    if color_err:
        return [TextContent(type="text", text=json.dumps(
            {"error": color_err}, ensure_ascii=False))]

    active = _active_profile()
    projects = load_projects()
    proj = next((p for p in projects if p["project_id"] == project_id), None)
    if not proj:
        return [TextContent(type="text", text=json.dumps(
            {"error": "Project not found"}, ensure_ascii=False))]

    # #1614: profile ownership check
    if not _profiles_match(proj.get("profile"), active):
        return [TextContent(type="text", text=json.dumps(
            {"error": "Project not found"}, ensure_ascii=False))]

    proj["name"] = name
    if color is not None:
        proj["color"] = color
    save_projects(projects)
    return [TextContent(type="text", text=json.dumps(proj, ensure_ascii=False, indent=2))]


async def handle_delete_project(arguments: dict) -> list[TextContent]:
    """Delete a project and unassign all its sessions (profile-checked)."""
    project_id = arguments.get("project_id")
    if not project_id:
        return [TextContent(type="text", text=json.dumps(
            {"error": "project_id is required"}, ensure_ascii=False))]

    active = _active_profile()
    projects = load_projects()
    proj = next((p for p in projects if p["project_id"] == project_id), None)
    if not proj:
        return [TextContent(type="text", text=json.dumps(
            {"error": "Project not found"}, ensure_ascii=False))]

    # #1614: profile ownership check
    if not _profiles_match(proj.get("profile"), active):
        return [TextContent(type="text", text=json.dumps(
            {"error": "Project not found"}, ensure_ascii=False))]

    projects = [p for p in projects if p["project_id"] != project_id]
    save_projects(projects)

    # Unassign sessions only when we can do it cache-safely via the HTTP API.
    # The previous filesystem fallback wrote session_data directly with
    # os.replace(), which bypassed _write_session_index() in api/models.py
    # and left _index.json holding the stale project_id — a running WebUI
    # would still group those sessions under the deleted project until a
    # subsequent re-compact. Even calling Session.save() in-process would
    # not help because the WebUI's SESSIONS dict cache (a separate process)
    # still has the old project_id and overwrites our update on its next
    # save. The HTTP API is the only cache-safe path; without auth we
    # refuse and surface the limitation so the operator can act.
    has_auth = bool(_api_password())
    if not has_auth:
        return [TextContent(type="text", text=json.dumps({
            "ok": True,
            "deleted": proj["name"],
            "unassigned_sessions": 0,
            "warning": "Set HERMES_WEBUI_PASSWORD to unassign sessions; "
                       "without auth the session index cannot be safely "
                       "updated and direct filesystem writes would cause "
                       "index drift in a running WebUI.",
        }, ensure_ascii=False))]

    unassigned = 0
    if SESSION_DIR.exists():
        for p in SESSION_DIR.glob("*.json"):
            if p.name.startswith("_"):
                continue
            try:
                session_data = json.loads(p.read_text(encoding="utf-8"))
                if session_data.get("project_id") == project_id:
                    sid = p.stem
                    result = _api_post("/api/session/move",
                                       {"session_id": sid, "project_id": None})
                    if "ok" in result or "session" in result:
                        unassigned += 1
            except Exception:
                pass

    return [TextContent(type="text", text=json.dumps({
        "ok": True,
        "deleted": proj["name"],
        "unassigned_sessions": unassigned,
    }, ensure_ascii=False))]


# ═══════════════════════════════════════════════════════════════════════════
#  Tool handlers — mutations (HTTP API with auth, cache-safe)
# ═══════════════════════════════════════════════════════════════════════════

async def handle_rename_session(arguments: dict) -> list[TextContent]:
    """Rename a session via the authenticated webui API (cache-safe)."""
    session_id = arguments.get("session_id")
    title = arguments.get("title", "").strip()[:80]
    if not session_id or not title:
        return [TextContent(type="text", text=json.dumps(
            {"error": "session_id and title are required"}, ensure_ascii=False))]

    result = _api_post("/api/session/rename",
                       {"session_id": session_id, "title": title})
    if "error" in result:
        return [TextContent(type="text", text=json.dumps(result, ensure_ascii=False))]

    session = result.get("session", {})
    return [TextContent(type="text", text=json.dumps({
        "ok": True,
        "session_id": session_id,
        "title": session.get("title", title),
        "method": "api",
    }, ensure_ascii=False, indent=2))]


async def handle_move_session(arguments: dict) -> list[TextContent]:
    """Assign a session to a project via the authenticated webui API (cache-safe)."""
    session_id = arguments.get("session_id")
    project_id = arguments.get("project_id")  # None/null = unassign
    if not session_id:
        return [TextContent(type="text", text=json.dumps(
            {"error": "session_id is required"}, ensure_ascii=False))]

    # If project_id is provided, verify it exists and is profile-accessible
    if project_id is not None:
        projects = load_projects()
        active = _active_profile()
        target = next((p for p in projects if p["project_id"] == project_id), None)
        if not target:
            return [TextContent(type="text", text=json.dumps(
                {"error": "Project not found"}, ensure_ascii=False))]
        # #1614: refuse moves into projects owned by another profile
        if not _profiles_match(target.get("profile"), active):
            return [TextContent(type="text", text=json.dumps(
                {"error": "Project not found"}, ensure_ascii=False))]

    result = _api_post("/api/session/move",
                       {"session_id": session_id, "project_id": project_id})
    if "error" in result:
        return [TextContent(type="text", text=json.dumps(result, ensure_ascii=False))]

    session = result.get("session", {})
    return [TextContent(type="text", text=json.dumps({
        "ok": True,
        "session_id": session_id,
        "project_id": project_id,
        "title": session.get("title"),
        "method": "api",
    }, ensure_ascii=False, indent=2))]


# ═══════════════════════════════════════════════════════════════════════════
#  MCP Server wiring
# ═══════════════════════════════════════════════════════════════════════════

TOOLS = [
    Tool(
        name="list_projects",
        description="List all session projects with their IDs, names, colors, and session counts (scoped to active profile).",
        inputSchema={"type": "object", "properties": {}, "required": []},
    ),
    Tool(
        name="create_project",
        description="Create a new project for organizing sessions (profile-scoped).",
        inputSchema={
            "type": "object",
            "properties": {
                "name": {"type": "string", "description": "Project name (max 128 chars)"},
                "color": {"type": "string", "description": "Optional hex color (#RGB, #RRGGBB, or #RRGGBBAA)"},
            },
            "required": ["name"],
        },
    ),
    Tool(
        name="rename_project",
        description="Rename a project and optionally change its color (profile-checked).",
        inputSchema={
            "type": "object",
            "properties": {
                "project_id": {"type": "string", "description": "12-char project ID"},
                "name": {"type": "string", "description": "New name (max 128 chars)"},
                "color": {"type": "string", "description": "Optional new hex color"},
            },
            "required": ["project_id", "name"],
        },
    ),
    Tool(
        name="delete_project",
        description="Delete a project and unassign all its sessions (profile-checked).",
        inputSchema={
            "type": "object",
            "properties": {
                "project_id": {"type": "string", "description": "12-char project ID to delete"},
            },
            "required": ["project_id"],
        },
    ),
    Tool(
        name="rename_session",
        description="Rename a session (updates sidebar via authenticated API, cache-safe).",
        inputSchema={
            "type": "object",
            "properties": {
                "session_id": {"type": "string", "description": "Session ID"},
                "title": {"type": "string", "description": "New title (max 80 chars)"},
            },
            "required": ["session_id", "title"],
        },
    ),
    Tool(
        name="move_session",
        description="Assign a session to a project. Pass project_id=null to unassign. Uses authenticated API for cache safety (profile-checked).",
        inputSchema={
            "type": "object",
            "properties": {
                "session_id": {"type": "string", "description": "Session ID"},
                "project_id": {"type": ["string", "null"], "description": "Project ID (or null to unassign)"},
            },
            "required": ["session_id", "project_id"],
        },
    ),
    Tool(
        name="list_sessions",
        description="List sessions, optionally filtered by project or unassigned status (profile-scoped).",
        inputSchema={
            "type": "object",
            "properties": {
                "project_id": {"type": "string", "description": "Filter sessions by project ID"},
                "unassigned": {"type": "boolean", "description": "Show only sessions with no project"},
                "limit": {"type": "integer", "description": "Max results (default: 50, max: 500)"},
            },
            "required": [],
        },
    ),
]

HANDLERS = {
    "list_projects": handle_list_projects,
    "create_project": handle_create_project,
    "rename_project": handle_rename_project,
    "delete_project": handle_delete_project,
    "rename_session": handle_rename_session,
    "move_session": handle_move_session,
    "list_sessions": handle_list_sessions,
}


@server.list_tools()
async def list_tools() -> list[Tool]:
    return TOOLS


@server.call_tool()
async def call_tool(name: str, arguments: dict) -> list[TextContent]:
    handler = HANDLERS.get(name)
    if not handler:
        return [TextContent(type="text", text=json.dumps(
            {"error": f"Unknown tool: {name}"}, ensure_ascii=False))]
    return await handler(arguments)


async def main():
    async with stdio_server() as (read, write):
        await server.run(read, write, server.create_initialization_options())


if __name__ == "__main__":
    import asyncio
    asyncio.run(main())