feat: add MCP search service

.env.example

@@ -2,15 +2,10 @@
 SERVER_PORT=8080
 FRONTEND_PORT=3000
 WEBSOCKET_PORT=8082
-MCP_PORT=9090
 MYSQL_PORT=3306
 REDIS_PORT=6379
 RABBITMQ_PORT=5672
 RABBITMQ_MANAGEMENT_PORT=15672
-MCP_HOST=0.0.0.0
-MCP_BACKEND_BASE_URL=http://springboot:8080
-MCP_CONNECT_TIMEOUT=5
-MCP_READ_TIMEOUT=10
 
 # === OpenSearch Configuration ===
 OPENSEARCH_PORT=9200

.gitignore

@@ -17,6 +17,7 @@ dist
 
 # misc
 .DS_Store
+__pycache__/
 *.pem
 npm-debug.log*
 yarn-debug.log*

deploy/deploy.sh

@@ -40,12 +40,12 @@ echo "👉 Build images ..."
 docker compose -f "$compose_file" --env-file "$env_file" \
   build --pull \
   --build-arg NUXT_ENV=production \
-  frontend_service mcp-service
+  frontend_service
 
 echo "👉 Recreate & start all target services (no dev profile)..."
 docker compose -f "$compose_file" --env-file "$env_file" \
   up -d --force-recreate --remove-orphans --no-deps \
-  mysql redis rabbitmq websocket-service springboot mcp-service frontend_service
+  mysql redis rabbitmq websocket-service springboot frontend_service
 
 echo "👉 Current status:"
 docker compose -f "$compose_file" --env-file "$env_file" ps

deploy/deploy_staging.sh

@@ -39,12 +39,12 @@ echo "👉 Build images (staging)..."
 docker compose -f "$compose_file" --env-file "$env_file" \
   build --pull \
   --build-arg NUXT_ENV=staging \
-  frontend_service mcp-service
+  frontend_service
 
 echo "👉 Recreate & start all target services (no dev profile)..."
 docker compose -f "$compose_file" --env-file "$env_file" \
   up -d --force-recreate --remove-orphans --no-deps \
-  mysql redis rabbitmq websocket-service springboot mcp-service frontend_service
+  mysql redis rabbitmq websocket-service springboot frontend_service
 
 echo "👉 Current status:"
 docker compose -f "$compose_file" --env-file "$env_file" ps

docker/docker-compose.yaml

@@ -178,38 +178,6 @@ services:
       - dev
       - prod
 
-  mcp-service:
-    build:
-      context: ..
-      dockerfile: mcp/Dockerfile
-    container_name: ${COMPOSE_PROJECT_NAME}-openisle-mcp
-    env_file:
-      - ${ENV_FILE:-../.env}
-    environment:
-      MCP_HOST: ${MCP_HOST:-0.0.0.0}
-      MCP_PORT: ${MCP_PORT:-9090}
-      MCP_BACKEND_BASE_URL: ${MCP_BACKEND_BASE_URL:-http://springboot:8080}
-      MCP_CONNECT_TIMEOUT: ${MCP_CONNECT_TIMEOUT:-5}
-      MCP_READ_TIMEOUT: ${MCP_READ_TIMEOUT:-10}
-    ports:
-      - "${MCP_PORT:-9090}:${MCP_PORT:-9090}"
-    depends_on:
-      springboot:
-        condition: service_healthy
-    command: ["openisle-mcp"]
-    healthcheck:
-      test: ["CMD-SHELL", "curl -fsS http://127.0.0.1:${MCP_PORT:-9090}/healthz || exit 1"]
-      interval: 10s
-      timeout: 5s
-      retries: 30
-      start_period: 20s
-    restart: unless-stopped
-    networks:
-      - openisle-network
-    profiles:
-      - dev
-      - prod
-
   websocket-service:
     image: maven:3.9-eclipse-temurin-17
     container_name: ${COMPOSE_PROJECT_NAME}-openisle-websocket
@@ -245,6 +213,32 @@ services:
       - dev_local_backend
       - prod
 
+  mcp-service:
+    build:
+      context: ..
+      dockerfile: mcp/Dockerfile
+    container_name: ${COMPOSE_PROJECT_NAME}-openisle-mcp
+    env_file:
+      - ${ENV_FILE:-../.env}
+    environment:
+      FASTMCP_HOST: 0.0.0.0
+      FASTMCP_PORT: ${MCP_PORT:-8765}
+      OPENISLE_BACKEND_URL: ${OPENISLE_BACKEND_URL:-http://springboot:8080}
+      OPENISLE_BACKEND_TIMEOUT: ${OPENISLE_BACKEND_TIMEOUT:-10}
+      OPENISLE_MCP_TRANSPORT: ${OPENISLE_MCP_TRANSPORT:-sse}
+      OPENISLE_MCP_SSE_MOUNT_PATH: ${OPENISLE_MCP_SSE_MOUNT_PATH:-/mcp}
+    ports:
+      - "${MCP_PORT:-8765}:${MCP_PORT:-8765}"
+    depends_on:
+      springboot:
+        condition: service_healthy
+    restart: unless-stopped
+    networks:
+      - openisle-network
+    profiles:
+      - dev
+      - prod
+
   frontend_dev:
     image: node:20
     container_name: ${COMPOSE_PROJECT_NAME}-openisle-frontend-dev

mcp/Dockerfile

@@ -1,21 +1,17 @@
-FROM python:3.11-slim
+FROM python:3.11-slim AS runtime
 
-ENV PYTHONDONTWRITEBYTECODE=1 \
-    PYTHONUNBUFFERED=1
+ENV PYTHONUNBUFFERED=1 \
+    PIP_NO_CACHE_DIR=1
 
 WORKDIR /app
 
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends curl \
-    && rm -rf /var/lib/apt/lists/*
+COPY mcp/pyproject.toml /app/pyproject.toml
+COPY mcp/README.md /app/README.md
+COPY mcp/src /app/src
 
-COPY mcp/pyproject.toml ./pyproject.toml
-COPY mcp/README.md ./README.md
-COPY mcp/src ./src
+RUN pip install --upgrade pip \
+    && pip install .
 
-RUN pip install --no-cache-dir --upgrade pip \
-    && pip install --no-cache-dir .
-
-EXPOSE 9090
+EXPOSE 8765
 
 CMD ["openisle-mcp"]

mcp/README.md

@@ -1,34 +1,39 @@
-# OpenIsle MCP Service
+# OpenIsle MCP Server
 
-This package hosts a lightweight Python service that exposes OpenIsle search
-capabilities through a Model Context Protocol (MCP) compatible HTTP interface.
-It currently forwards search requests to the main Spring Boot backend and
-returns the aggregated results. The service is intentionally simple so we can
-iterate quickly and extend it with additional tools (for example, post
-creation) in future updates.
+This package provides a [Model Context Protocol](https://github.com/modelcontextprotocol) (MCP) server that exposes the OpenIsle
+search capabilities to AI assistants. The server wraps the existing Spring Boot backend and currently provides a single `search`
+tool. Future iterations can extend the server with additional functionality such as publishing new posts or moderating content.
+
+## Features
+
+- 🔍 **Global search** — delegates to the existing `/api/search/global` endpoint exposed by the OpenIsle backend.
+- 🧠 **Structured results** — responses include highlights and deep links so AI clients can present the results cleanly.
+- ⚙️ **Configurable** — point the server at any reachable OpenIsle backend by setting environment variables.
 
 ## Local development
 
 ```bash
-pip install -e ./mcp
-openisle-mcp
+cd mcp
+python -m venv .venv
+source .venv/bin/activate
+pip install -e .
+openisle-mcp --transport stdio  # or "sse"/"streamable-http"
 ```
 
-By default the server listens on port `9090` and expects the Spring Boot backend
-at `http://localhost:8080`. Configure the behaviour with the following
-environment variables:
+Environment variables:
 
-- `MCP_PORT` – HTTP port the MCP service should listen on (default: `9090`).
-- `MCP_HOST` – Bind host for the HTTP server (default: `0.0.0.0`).
-- `MCP_BACKEND_BASE_URL` – Base URL of the Spring Boot backend that provides the
-  search endpoints (default: `http://springboot:8080`).
-- `MCP_CONNECT_TIMEOUT` – Connection timeout (seconds) when calling the backend
-  (default: `5`).
-- `MCP_READ_TIMEOUT` – Read timeout (seconds) when calling the backend (default:
-  `10`).
+| Variable | Description | Default |
+| --- | --- | --- |
+| `OPENISLE_BACKEND_URL` | Base URL of the Spring Boot backend | `http://springboot:8080` |
+| `OPENISLE_BACKEND_TIMEOUT` | Timeout (seconds) for backend HTTP calls | `10` |
+| `OPENISLE_PUBLIC_BASE_URL` | Optional base URL used to build deep links in search results | *(unset)* |
+| `OPENISLE_MCP_TRANSPORT` | MCP transport (`stdio`, `sse`, `streamable-http`) | `stdio` |
+| `OPENISLE_MCP_SSE_MOUNT_PATH` | Mount path when using SSE transport | `/mcp` |
+| `FASTMCP_HOST` | Host for SSE / HTTP transports | `127.0.0.1` |
+| `FASTMCP_PORT` | Port for SSE / HTTP transports | `8000` |
 
 ## Docker
 
-The repository contains a Dockerfile that builds a slim Python image running the
-service with `uvicorn`. The compose configuration wires the container into the
-existing OpenIsle stack so that deployments automatically start the MCP service.
+A dedicated Docker image is provided and wired into `docker-compose.yaml`. The container listens on
+`${MCP_PORT:-8765}` and connects to the backend service running in the same compose stack.
+

mcp/pyproject.toml

@@ -1,25 +1,29 @@
 [build-system]
-requires = ["hatchling>=1.21.0"]
-build-backend = "hatchling.build"
+requires = ["setuptools>=68", "wheel"]
+build-backend = "setuptools.build_meta"
 
 [project]
 name = "openisle-mcp"
 version = "0.1.0"
 description = "Model Context Protocol server exposing OpenIsle search capabilities"
 readme = "README.md"
-authors = [
-  { name = "OpenIsle" }
-]
+authors = [{name = "OpenIsle Team"}]
+license = {text = "MIT"}
 requires-python = ">=3.11"
 dependencies = [
-  "fastapi>=0.111.0,<1.0.0",
-  "uvicorn[standard]>=0.29.0,<0.31.0",
-  "httpx>=0.27.0,<0.28.0",
-  "pydantic>=2.7.0,<3.0.0"
+  "mcp>=1.19.0",
+  "httpx>=0.28.0",
+  "pydantic>=2.12.0",
 ]
 
 [project.scripts]
-openisle-mcp = "openisle_mcp.__main__:main"
+openisle-mcp = "openisle_mcp.server:main"
 
-[tool.hatch.build.targets.wheel]
-packages = ["src/openisle_mcp"]
+[tool.setuptools]
+package-dir = {"" = "src"}
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.setuptools.package-data]
+openisle_mcp = ["py.typed"]

mcp/src/openisle_mcp/__init__.py

@@ -1,6 +1,10 @@
-"""OpenIsle MCP service package."""
+"""OpenIsle MCP server package."""
 
-from .config import Settings, get_settings
-from .server import create_app
+from importlib import metadata
 
-__all__ = ["Settings", "get_settings", "create_app"]
+try:
+    __version__ = metadata.version("openisle-mcp")
+except metadata.PackageNotFoundError:  # pragma: no cover - best effort during dev
+    __version__ = "0.0.0"
+
+__all__ = ["__version__"]

mcp/src/openisle_mcp/__main__.py

@@ -1,24 +0,0 @@
-"""Entrypoint for running the MCP service with ``python -m``."""
-
-from __future__ import annotations
-
-import logging
-
-import uvicorn
-
-from .config import get_settings
-
-
-def main() -> None:
-    settings = get_settings()
-    logging.basicConfig(level=logging.INFO)
-    uvicorn.run(
-        "openisle_mcp.server:create_app",
-        host=settings.host,
-        port=settings.port,
-        factory=True,
-    )
-
-
-if __name__ == "__main__":  # pragma: no cover
-    main()

mcp/src/openisle_mcp/client.py

@@ -1,44 +1,79 @@
-"""HTTP client helpers for talking to the Spring Boot backend."""
+"""HTTP client for talking to the OpenIsle backend."""
 
 from __future__ import annotations
 
+import json
 import logging
-from typing import Any
+from typing import List
 
 import httpx
+from pydantic import ValidationError
 
-from .config import Settings
+from .models import BackendSearchResult
 
-LOGGER = logging.getLogger(__name__)
+__all__ = ["BackendClientError", "OpenIsleBackendClient"]
+
+logger = logging.getLogger(__name__)
 
 
-class SearchClient:
-    """Wrapper around :class:`httpx.AsyncClient` for search operations."""
-
-    def __init__(self, settings: Settings):
-        timeout = httpx.Timeout(
-            connect=settings.connect_timeout,
-            read=settings.read_timeout,
-            write=settings.read_timeout,
-            pool=None,
-        )
-        self._client = httpx.AsyncClient(
-            base_url=settings.normalized_backend_base_url,
-            timeout=timeout,
-        )
-
-    async def close(self) -> None:
-        await self._client.aclose()
-
-    async def global_search(self, keyword: str) -> list[dict[str, Any]]:
-        LOGGER.debug("Performing global search for keyword '%s'", keyword)
-        response = await self._client.get("/api/search/global", params={"keyword": keyword})
-        response.raise_for_status()
-        payload = response.json()
-        if isinstance(payload, list):
-            return payload
-        LOGGER.warning("Unexpected payload type from backend: %s", type(payload))
-        return []
+class BackendClientError(RuntimeError):
+    """Raised when the backend cannot fulfil a request."""
 
 
-__all__ = ["SearchClient"]
+class OpenIsleBackendClient:
+    """Tiny wrapper around the Spring Boot search endpoints."""
+
+    def __init__(self, base_url: str, timeout: float = 10.0) -> None:
+        if not base_url:
+            raise ValueError("base_url must not be empty")
+        self._base_url = base_url.rstrip("/")
+        timeout = timeout if timeout > 0 else 10.0
+        self._timeout = httpx.Timeout(timeout, connect=timeout, read=timeout)
+
+    @property
+    def base_url(self) -> str:
+        return self._base_url
+
+    async def search_global(self, keyword: str) -> List[BackendSearchResult]:
+        """Call `/api/search/global` and normalise the payload."""
+
+        url = f"{self._base_url}/api/search/global"
+        params = {"keyword": keyword}
+        headers = {"Accept": "application/json"}
+        logger.debug("Calling OpenIsle backend", extra={"url": url, "params": params})
+
+        try:
+            async with httpx.AsyncClient(timeout=self._timeout, headers=headers, follow_redirects=True) as client:
+                response = await client.get(url, params=params)
+                response.raise_for_status()
+        except httpx.HTTPStatusError as exc:  # pragma: no cover - network errors are rare in tests
+            body_preview = _truncate_body(exc.response.text)
+            raise BackendClientError(
+                f"Backend returned HTTP {exc.response.status_code}: {body_preview}"
+            ) from exc
+        except httpx.RequestError as exc:  # pragma: no cover - network errors are rare in tests
+            raise BackendClientError(f"Failed to reach backend: {exc}") from exc
+
+        try:
+            payload = response.json()
+        except json.JSONDecodeError as exc:
+            raise BackendClientError("Backend returned invalid JSON") from exc
+
+        if not isinstance(payload, list):
+            raise BackendClientError("Unexpected search payload type; expected a list")
+
+        results: list[BackendSearchResult] = []
+        for item in payload:
+            try:
+                results.append(BackendSearchResult.model_validate(item))
+            except ValidationError as exc:
+                raise BackendClientError(f"Invalid search result payload: {exc}") from exc
+
+        return results
+
+
+def _truncate_body(body: str, limit: int = 200) -> str:
+    body = body.strip()
+    if len(body) <= limit:
+        return body
+    return f"{body[:limit]}…"

mcp/src/openisle_mcp/config.py

@@ -1,71 +0,0 @@
-"""Configuration helpers for the MCP service."""
-
-from __future__ import annotations
-
-import os
-from functools import lru_cache
-from typing import Any
-
-from pydantic import BaseModel, ConfigDict, Field, ValidationError
-
-
-class Settings(BaseModel):
-    """Application settings sourced from environment variables."""
-
-    host: str = Field(default="0.0.0.0", description="Host to bind the HTTP server to")
-    port: int = Field(default=9090, ge=1, le=65535, description="Port exposed by the MCP server")
-    backend_base_url: str = Field(
-        default="http://springboot:8080",
-        description="Base URL of the Spring Boot backend that provides search endpoints",
-    )
-    connect_timeout: float = Field(
-        default=5.0,
-        ge=0.0,
-        description="Connection timeout when communicating with the backend (seconds)",
-    )
-    read_timeout: float = Field(
-        default=10.0,
-        ge=0.0,
-        description="Read timeout when communicating with the backend (seconds)",
-    )
-
-    model_config = ConfigDict(extra="ignore")
-
-    @property
-    def normalized_backend_base_url(self) -> str:
-        """Return the backend base URL without a trailing slash."""
-
-        return self.backend_base_url.rstrip("/")
-
-
-ENV_MAPPING: dict[str, str] = {
-    "host": "MCP_HOST",
-    "port": "MCP_PORT",
-    "backend_base_url": "MCP_BACKEND_BASE_URL",
-    "connect_timeout": "MCP_CONNECT_TIMEOUT",
-    "read_timeout": "MCP_READ_TIMEOUT",
-}
-
-
-def _load_environment_values() -> dict[str, Any]:
-    values: dict[str, Any] = {}
-    for field, env_name in ENV_MAPPING.items():
-        value = os.getenv(env_name)
-        if value is None:
-            continue
-        values[field] = value
-    return values
-
-
-@lru_cache(maxsize=1)
-def get_settings() -> Settings:
-    """Load and validate application settings."""
-
-    values = _load_environment_values()
-    try:
-        return Settings(**values)
-    except ValidationError as exc:  # pragma: no cover - defensive branch
-        raise RuntimeError("Invalid MCP configuration") from exc
-
-
-__all__ = ["Settings", "get_settings"]

mcp/src/openisle_mcp/models.py

@@ -1,38 +1,58 @@
-"""Pydantic models shared across the MCP service."""
+"""Pydantic models used by the OpenIsle MCP server."""
 
 from __future__ import annotations
 
-from typing import Optional
+from typing import Dict, Optional
 
 from pydantic import BaseModel, ConfigDict, Field
 
+__all__ = [
+    "BackendSearchResult",
+    "SearchResult",
+    "SearchResponse",
+]
+
+
+class BackendSearchResult(BaseModel):
+    """Shape of the payload returned by the OpenIsle backend."""
+
+    type: str
+    id: Optional[int] = None
+    text: Optional[str] = None
+    sub_text: Optional[str] = Field(default=None, alias="subText")
+    extra: Optional[str] = None
+    post_id: Optional[int] = Field(default=None, alias="postId")
+    highlighted_text: Optional[str] = Field(default=None, alias="highlightedText")
+    highlighted_sub_text: Optional[str] = Field(default=None, alias="highlightedSubText")
+    highlighted_extra: Optional[str] = Field(default=None, alias="highlightedExtra")
+
+    model_config = ConfigDict(populate_by_name=True, extra="ignore")
+
 
 class SearchResult(BaseModel):
-    """Representation of a single search result entry."""
+    """Structured search result returned to MCP clients."""
 
-    model_config = ConfigDict(extra="ignore")
+    type: str = Field(description="Entity type, e.g. post, comment, user")
+    id: Optional[int] = Field(default=None, description="Primary identifier for the entity")
+    title: Optional[str] = Field(default=None, description="Primary text to display")
+    subtitle: Optional[str] = Field(default=None, description="Secondary text (e.g. author or category)")
+    extra: Optional[str] = Field(default=None, description="Additional descriptive snippet")
+    post_id: Optional[int] = Field(default=None, description="Associated post id for comment results")
+    url: Optional[str] = Field(default=None, description="Deep link to the resource inside OpenIsle")
+    highlights: Dict[str, Optional[str]] = Field(
+        default_factory=dict,
+        description="Highlighted HTML fragments keyed by field name",
+    )
 
-    type: Optional[str] = Field(default=None, description="Type of the result entry")
-    id: Optional[int] = Field(default=None, description="Identifier of the result entry")
-    text: Optional[str] = Field(default=None, description="Primary text of the result entry")
-    subText: Optional[str] = Field(default=None, description="Secondary text associated with the result")
-    extra: Optional[str] = Field(default=None, description="Additional information about the result")
-    postId: Optional[int] = Field(default=None, description="Related post identifier, if applicable")
-    highlightedText: Optional[str] = Field(default=None, description="Highlighted primary text segment")
-    highlightedSubText: Optional[str] = Field(
-        default=None,
-        description="Highlighted secondary text segment",
-    )
-    highlightedExtra: Optional[str] = Field(
-        default=None,
-        description="Highlighted additional information",
-    )
+    model_config = ConfigDict(populate_by_name=True)
 
 
 class SearchResponse(BaseModel):
-    """Response payload returned by the search endpoint."""
+    """Response envelope returned from the MCP search tool."""
 
-    results: list[SearchResult] = Field(default_factory=list)
+    keyword: str = Field(description="Sanitised keyword that was searched for")
+    total_results: int = Field(description="Total number of results returned by the backend")
+    limit: int = Field(description="Maximum number of results included in the response")
+    results: list[SearchResult] = Field(default_factory=list, description="Search results up to the requested limit")
 
-
-__all__ = ["SearchResult", "SearchResponse"]
+    model_config = ConfigDict(populate_by_name=True)

mcp/src/openisle_mcp/server.py

@@ -1,66 +1,164 @@
-"""FastAPI application exposing the MCP server endpoints."""
+"""Entry point for the OpenIsle MCP server."""
 
 from __future__ import annotations
 
+import argparse
 import logging
+import os
+from typing import Annotated, Optional
 
-from fastapi import Depends, FastAPI, HTTPException, Query, Request
-import httpx
+from mcp.server.fastmcp import Context, FastMCP
+from mcp.server.fastmcp import exceptions as mcp_exceptions
+from pydantic import Field
 
-from .client import SearchClient
-from .config import get_settings
-from .models import SearchResponse, SearchResult
+from .client import BackendClientError, OpenIsleBackendClient
+from .models import BackendSearchResult, SearchResponse, SearchResult
 
-LOGGER = logging.getLogger(__name__)
+logger = logging.getLogger(__name__)
+
+APP_NAME = "openisle-mcp"
+DEFAULT_BACKEND_URL = "http://springboot:8080"
+DEFAULT_TRANSPORT = "stdio"
+DEFAULT_TIMEOUT = 10.0
+DEFAULT_LIMIT = 20
+MAX_LIMIT = 50
+
+server = FastMCP(
+    APP_NAME,
+    instructions=(
+        "Use the `search` tool to query OpenIsle content. "
+        "Results include posts, comments, users, categories, and tags."
+    ),
+)
 
 
-async def _lifespan(app: FastAPI):
-    settings = get_settings()
-    client = SearchClient(settings)
-    app.state.settings = settings
-    app.state.search_client = client
-    LOGGER.info(
-        "Starting MCP server on %s:%s targeting backend %s",
-        settings.host,
-        settings.port,
-        settings.normalized_backend_base_url,
-    )
+def _env(name: str, default: Optional[str] = None) -> Optional[str]:
+    value = os.getenv(name, default)
+    if value is None:
+        return None
+    trimmed = value.strip()
+    return trimmed or default
+
+
+def _load_timeout() -> float:
+    raw = _env("OPENISLE_BACKEND_TIMEOUT", str(DEFAULT_TIMEOUT))
     try:
-        yield
-    finally:
-        LOGGER.info("Shutting down MCP server")
-        await client.close()
+        timeout = float(raw) if raw is not None else DEFAULT_TIMEOUT
+    except ValueError:
+        logger.warning("Invalid OPENISLE_BACKEND_TIMEOUT value '%s', falling back to %s", raw, DEFAULT_TIMEOUT)
+        return DEFAULT_TIMEOUT
+    if timeout <= 0:
+        logger.warning("Non-positive OPENISLE_BACKEND_TIMEOUT %s, falling back to %s", timeout, DEFAULT_TIMEOUT)
+        return DEFAULT_TIMEOUT
+    return timeout
 
 
-def create_app() -> FastAPI:
-    """Create and configure the FastAPI application."""
-
-    app = FastAPI(title="OpenIsle MCP Server", lifespan=_lifespan)
-
-    @app.get("/healthz", tags=["health"])
-    async def healthcheck() -> dict[str, str]:
-        return {"status": "ok"}
-
-    async def get_client(request: Request) -> SearchClient:
-        return request.app.state.search_client
-
-    @app.get("/search", response_model=SearchResponse, tags=["search"])
-    async def search(
-        keyword: str = Query(..., min_length=1, description="Keyword to search for"),
-        client: SearchClient = Depends(get_client),
-    ) -> SearchResponse:
-        try:
-            raw_results = await client.global_search(keyword)
-        except httpx.HTTPStatusError as exc:
-            LOGGER.warning("Backend responded with error %s", exc.response.status_code)
-            raise HTTPException(status_code=exc.response.status_code, detail="Backend error") from exc
-        except httpx.HTTPError as exc:
-            LOGGER.error("Failed to reach backend: %s", exc)
-            raise HTTPException(status_code=503, detail="Search service unavailable") from exc
-        results = [SearchResult.model_validate(item) for item in raw_results]
-        return SearchResponse(results=results)
-
-    return app
+_BACKEND_CLIENT = OpenIsleBackendClient(
+    base_url=_env("OPENISLE_BACKEND_URL", DEFAULT_BACKEND_URL) or DEFAULT_BACKEND_URL,
+    timeout=_load_timeout(),
+)
+_PUBLIC_BASE_URL = _env("OPENISLE_PUBLIC_BASE_URL")
 
 
-__all__ = ["create_app"]
+def _build_url(result: BackendSearchResult) -> Optional[str]:
+    if not _PUBLIC_BASE_URL:
+        return None
+    base = _PUBLIC_BASE_URL.rstrip("/")
+    if result.type in {"post", "post_title"} and result.id is not None:
+        return f"{base}/posts/{result.id}"
+    if result.type == "comment" and result.post_id is not None:
+        anchor = f"#comment-{result.id}" if result.id is not None else ""
+        return f"{base}/posts/{result.post_id}{anchor}"
+    if result.type == "user" and result.id is not None:
+        return f"{base}/users/{result.id}"
+    if result.type == "category" and result.id is not None:
+        return f"{base}/?categoryId={result.id}"
+    if result.type == "tag" and result.id is not None:
+        return f"{base}/?tagIds={result.id}"
+    return None
+
+
+def _to_search_result(result: BackendSearchResult) -> SearchResult:
+    highlights = {
+        "text": result.highlighted_text,
+        "subText": result.highlighted_sub_text,
+        "extra": result.highlighted_extra,
+    }
+    # Remove empty highlight entries to keep the payload clean
+    highlights = {key: value for key, value in highlights.items() if value}
+    return SearchResult(
+        type=result.type,
+        id=result.id,
+        title=result.text,
+        subtitle=result.sub_text,
+        extra=result.extra,
+        post_id=result.post_id,
+        url=_build_url(result),
+        highlights=highlights,
+    )
+
+
+KeywordParam = Annotated[str, Field(description="Keyword to search for", min_length=1)]
+LimitParam = Annotated[
+    int,
+    Field(ge=1, le=MAX_LIMIT, description=f"Maximum number of results to return (<= {MAX_LIMIT})"),
+]
+
+
+@server.tool(name="search", description="Search OpenIsle content")
+async def search(keyword: KeywordParam, limit: LimitParam = DEFAULT_LIMIT, ctx: Optional[Context] = None) -> SearchResponse:
+    """Run a search query against the OpenIsle backend."""
+
+    trimmed = keyword.strip()
+    if not trimmed:
+        raise mcp_exceptions.ToolError("Keyword must not be empty")
+
+    if ctx is not None:
+        await ctx.debug(f"Searching OpenIsle for '{trimmed}' (limit={limit})")
+
+    try:
+        raw_results = await _BACKEND_CLIENT.search_global(trimmed)
+    except BackendClientError as exc:
+        if ctx is not None:
+            await ctx.error(f"Search request failed: {exc}")
+        raise mcp_exceptions.ToolError(f"Search failed: {exc}") from exc
+
+    results = [_to_search_result(result) for result in raw_results]
+    limited = results[:limit]
+
+    if ctx is not None:
+        await ctx.info(
+            "Search completed",
+            keyword=trimmed,
+            total_results=len(results),
+            returned=len(limited),
+        )
+
+    return SearchResponse(keyword=trimmed, total_results=len(results), limit=limit, results=limited)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Run the OpenIsle MCP server")
+    parser.add_argument(
+        "--transport",
+        choices=["stdio", "sse", "streamable-http"],
+        default=_env("OPENISLE_MCP_TRANSPORT", DEFAULT_TRANSPORT),
+        help="Transport protocol to use",
+    )
+    parser.add_argument(
+        "--mount-path",
+        default=_env("OPENISLE_MCP_SSE_MOUNT_PATH", "/mcp"),
+        help="Mount path when using the SSE transport",
+    )
+    args = parser.parse_args()
+
+    logging.basicConfig(level=os.getenv("OPENISLE_MCP_LOG_LEVEL", "INFO"))
+    logger.info(
+        "Starting OpenIsle MCP server", extra={"transport": args.transport, "backend": _BACKEND_CLIENT.base_url}
+    )
+
+    server.run(transport=args.transport, mount_path=args.mount_path)
+
+
+if __name__ == "__main__":
+    main()