agentifyapi

Make your FastAPI services agent-ready with owner-approved MCP tools.

Install

pip install agentifyapi

Python 3.11 or newer.

For the latest commit on main:

pip install "git+https://github.com/SomilAgg123/agentifyapi"

Related MCP server: MCP Flow

Example

A tiny FastAPI app. One mount(app) call adds a governed /mcp endpoint. Routes become MCP tools, but they stay hidden until you approve them.

# examples/quickstart.py
from fastapi import FastAPI
from agentifyapi import mount
from agentifyapi.config import PolicyConfig

app = FastAPI(title="inventory")


@app.get("/stock/{sku}")
def get_stock(sku: str) -> dict:
    """Units on hand for a SKU."""
    return {"sku": sku, "on_hand": 42, "warehouse": "nyc"}


mount(app, owner="you", database="quickstart.db", policy=PolicyConfig(allow_anonymous=True))  # local demo only

uvicorn examples.quickstart:app --port 8200
# another terminal:
agentifyapi --db quickstart.db tools list
# inventory.get_stock   -   disabled   1
agentifyapi --db quickstart.db tools approve inventory.get_stock --by you   # approved, still disabled
agentifyapi --db quickstart.db tools enable inventory.get_stock            # now agents can call it

An MCP client pointed at http://127.0.0.1:8200/mcp then discovers and calls the tool:

>>> list_tools(server="inventory")          # before approve → []
>>> invoke_tool(tool="inventory.get_stock", args={"sku": "KB-1"})
{"sku": "KB-1", "on_hand": 42, "warehouse": "nyc"}

From a clone of this repo, uv run python scripts/verify_quickstart.py runs the whole flow (CI runs it on every push). For many services behind one gateway, see Standalone gateway.

How this differs from fastapi_mcp and FastMCP

fastapi_mcp and FastMCP (FastMCP.from_fastapi / from_openapi) are the quickest ways to expose FastAPI routes as MCP tools. Use them if you want every selected route live immediately. agentifyapi converts routes too, but its focus is what happens around the tools when many teams' APIs are involved.

A dash means that control is not built in. The other projects have strengths this one doesn't, such as broader MCP feature coverage and richer authentication. agentifyapi is young (0.x).

Inspired by Uber's Designing MCP Gateway, rebuilt as a small open-source project for the FastAPI ecosystem. Not affiliated with Uber.

Why

Architecture

flowchart LR
  subgraph Sources
    A1[FastAPI app<br/>myservice.main:app] -->|import + introspect| C
    A2[Running service<br/>/openapi.json] -->|HTTP| C
    A3[Protobuf / gRPC<br/>roadmap] -.-> C
  end
  C[Crawler<br/>schema translation<br/>LLM or template descriptions<br/>contract hash] -->|pending revisions| R[(Registry<br/>SQLite, versioned)]
  O[Owner<br/>CLI / admin UI] -->|diff, approve, enable, rollback| R
  R -->|approved + enabled only| G[Gateway<br/>/mcp meta-tools<br/>/servers/name/mcp]
  AG[Agents and coding agents<br/>MCP client] <-->|streamable HTTP + API key| G
  G -->|policy, forward, project, redact, audit| S[Your FastAPI services]

Two deployment shapes share the same core.

• Embedded. mount(app) serves one service with in-process dispatch and no extra deployment.

• Standalone gateway. agentifyapi serve puts many services behind one MCP endpoint and re-crawls them on an interval.

Standalone gateway

With pip only

Put the gateway in front of a FastAPI service that is already running (here on port 8300). Write a small config.yaml with the registry path and who may call what:

# config.yaml
database: registry.db
policy:
  api_keys:
    my-agent-key: { name: my-agent, roles: [agent] }
  rules:
    - tools: ["inventory.*"]
      roles: [agent]

pip install agentifyapi
agentifyapi -c config.yaml crawl --url http://127.0.0.1:8300 --name inventory   # reads /openapi.json
agentifyapi -c config.yaml tools list
agentifyapi -c config.yaml tools approve "inventory.*" --by you   # approved, still disabled
agentifyapi -c config.yaml tools enable inventory.get_stock       # now agents can call it
agentifyapi -c config.yaml serve --port 8000

Agents connect to http://127.0.0.1:8000/mcp with the header x-api-key: my-agent-key. To crawl by importing the app instead, use crawl --app myservice.main:app --base-url http://127.0.0.1:8300 from the service's directory (or pass --app-dir).

Demo from a clone

git clone https://github.com/SomilAgg123/agentifyapi && cd agentifyapi
uv sync                          # or: pip install -e ".[dev]"
uv run python scripts/run_demo.py   # `make demo` does the same

The demo starts two mock FastAPI services (orders, users) and crawls them. Orders is crawled by importing the app, and users over HTTP. It then shows a diff, approves three tools, starts the gateway on :8000, and runs examples/agent_client.py, an MCP SDK client that discovers and calls tools.

>>> invoke_tool({"tool": "orders.get_order", "args": {"order_id": 101}, "fields": ["id", "status", "items.sku", "card_number", "shipping_note"]})
{ "id": 101, "status": "shipped", "items": [{"sku": "KB-1"}],
  "card_number": "[REDACTED:card]", "shipping_note": "Call [REDACTED:phone] on arrival" }

uv run python scripts/run_demo.py --keep leaves it running so you can open the admin UI at http://127.0.0.1:8000/admin/.

uv run python scripts/verify_demo.py (or make verify) boots the same demo and checks 8 behaviors against it over real MCP HTTP: discovery, approval gating, projection, redaction, policy denial, the per-server endpoint, the admin UI, and the audit log.

Connect a coding agent

Point any MCP client that speaks streamable HTTP at http://127.0.0.1:8000/mcp with the header x-api-key: demo-support-key (or Authorization: Bearer ...). If you prefer a flat tool list, use http://127.0.0.1:8000/servers/orders/mcp. Each enabled tool appears there directly, with an optional _fields argument.

The approval flow

crawl ──► v1 pending ──approve──► v1 live (disabled) ──enable──► served to agents
   spec changes ──► v2 pending (v1 keeps serving) ──approve──► v2 live ──rollback──► v1 live
   endpoint removed upstream ──► hidden + disabled, history kept

• Changes are detected with a hash of the tool contract (method, path, schemas, docs). The generated description is excluded, so LLM wording never creates noise revisions.

• agentifyapi tools list | diff | approve | reject | enable | disable | rollback | history <tool>. server.* works for bulk actions; bulk approve and reject skip tools with nothing pending. --by records the reviewer.

• The admin UI (/admin standalone, /mcp-admin embedded) shows the same diff with buttons.

• To exclude a route entirely, use @app.post(..., openapi_extra={"x-agentifyapi-exclude": True}).

FastAPI-native introspection

--app module:app (or app: in config) imports your app, including app factories, and walks its APIRoutes. On top of app.openapi() it recovers these details.

• Clean tool names from the route function (get_order, not get_order_orders__order_id__get).

• Full docstrings as tool documentation.

• The Depends() graph (for example require_admin), shown to reviewers in the diff.

• Exact Pydantic request and response schemas with $refs inlined. Recursive models are cut safely.

If the import fails (missing dependencies or environment) and a base_url is set, it falls back to /openapi.json.

Configuration reference

database: registry.db          # SQLite registry
audit_log: audit.log           # JSON lines; "" to disable
crawl_interval_seconds: 300    # 0 = on demand only
redact_pii: true

services:
  - name: orders               # tool names become orders.<route_name>
    owner: team-commerce
    app: services.orders.main:app   # FastAPI-native crawl (optional)
    app_dir: ../orders-repo         # put this repo on sys.path first (optional)
    base_url: http://orders:8000    # where calls are forwarded (+ /openapi.json fallback)
    openapi_url: http://...         # override spec location (optional)
    # proto: path/to/descriptor.pb  # extension point, not implemented in v1

policy:
  allow_anonymous: false       # dev only: callers without a key may use any enabled tool
  api_keys:
    <key>: { name: support-agent, roles: [support] }
  rules:                       # allow-list, default deny; discovery hides tools a caller can't invoke
    - tools: ["orders.*"]      # fnmatch on tool names
      roles: [support]
      callers: [some-agent]

admin:                         # admin UI (/admin, /mcp-admin) access
  username: admin
  password: null               # set to require HTTP Basic auth; null = localhost-only
  insecure_allow_remote: false # dev only: no password and reachable from anywhere

mount(app, name=, owner=, database=, policy=, prefix=, admin_path=, auto_approve=False, redact_pii=True, audit_log=, admin_password=None, admin_username="admin", admin_allow_remote=False). auto_approve=True is for local development only. Without an admin password the admin UI only answers localhost; see SECURITY.md.

Development

uv sync && uv run pre-commit install
uv run pytest --cov && uv run pyright
uv run python scripts/verify_quickstart.py   # README example
uv run python scripts/verify_demo.py         # multi-service gateway

See CONTRIBUTING.md, AGENTS.md for coding agents, and SECURITY.md to report vulnerabilities.

The tests cover schema translation, FastAPI introspection, the crawler and approval flow (with a fake spec), the CLI, the admin UI, projection, redaction, and policy. Two end-to-end runs go over real MCP streamable HTTP: the standalone gateway against a live mock service, and embedded mount().

Roadmap

• gRPC / Protobuf crawling from descriptor sets (proto: is a stub today).

• OAuth passthrough for third-party APIs and end-user identity propagation.

• Code-mode CLI that writes tool output to files so coding agents grep them instead of loading results into context.

• Semantic discovery index with embeddings for discover_servers and list_tools (keyword scoring today).

• Field-level PII policy from Pydantic annotations, per-caller rate limits, OpenTelemetry traces.

• Postgres registry and multi-reviewer approvals.

Credits

The architecture follows the ideas in Uber Engineering's Designing MCP Gateway. Those ideas are crawling existing API definitions, registering virtual MCP servers disabled by default, owner approval, incremental discovery, response projection, and PII stripping. Built on the official MCP Python SDK and FastAPI.

MIT licensed. See CONTRIBUTING.md, docs/DESIGN.md and docs/DECISIONS.md.