rest-api-mcp

v1.5.0

Published

a month ago

MCP server for authenticated REST API calls — auto-login, Swagger spec fetch, and guided Flutter implementation

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rest-api-mcp

A Model Context Protocol (MCP) server for authenticated REST APIs.
Drop it into any project, point it at your API, and let AI agents call endpoints — with auto-login, 2FA support, Swagger spec fetch, and fuzzy endpoint search — all without writing a single line of auth code.

Features

| Capability | Description | |---|---| | Auto-login | Logs in automatically before every request; re-logins when token expires | | Token caching | 20-second TTL cache — survives rapid sequential calls | | Auto-discovery | Finds the login endpoint by scanning the Swagger spec (no config needed) | | Auto token detection | Tries 9 common token paths (data.access_token, accessToken, token, …) | | AI-driven token detection | inspect_login tool exposes raw responses + heuristic suggestions so the AI can pick the exact token path | | 2FA / OTP support | Two-step auth: login → verify-otp, session identifiers forwarded automatically | | Custom session fields | Override hardcoded session candidates via verify_session_fields in request() | | Extra login fields | source, userRole, channel, device_id — any field, via JSON env var | | Fuzzy endpoint search | Find endpoints by keyword across path, summary, description, tags, operationId | | Swagger spec fetch | Retrieve and inspect the full OpenAPI spec | | SSL bypass | Optional for staging/dev environments with self-signed certs | | Response truncation | Configurable size limit to keep responses in context |

Installation

Option A — Use via npx (recommended)

No installation needed. Add this to your project's .vscode/mcp.json and VS Code will download and run the package automatically:

{
  "command": "npx",
  "args": ["-y", "rest-api-mcp"]
}

This always uses the latest published version from npm. See VS Code mcp.json Examples for a full config.

Option B — Use locally (for development / offline)

git clone https://github.com/Muhammed-AbdelGhany/rest_api_mcp
cd rest_api_mcp
npm install && npm run build

Then point VS Code at the local build:

{
  "command": "node",
  "args": ["/path/to/rest_api_mcp/build/index.js"]
}

Quick Start

Add this to your project's .vscode/mcp.json:

{
  "servers": {
    "my-api": {
      "command": "npx",
      "args": ["-y", "rest-api-mcp"],
      "env": {
        "REST_BASE_URL": "https://api.example.com/api/v1",
        "API_EMAIL": "[email protected]",
        "API_PASSWORD": "yourpassword",
        "API_SWAGGER_URL": "https://api.example.com/docs-json"
      }
    }
  }
}

That's it. The agent can now:

Search for endpoints by keyword
Call any endpoint with automatic authentication
Fetch the full OpenAPI spec for schema inspection

Configuration

All configuration is done via environment variables in mcp.json. No code changes required.

Minimum required

| Variable | Description | |---|---| | REST_BASE_URL | Base URL of the API (no trailing slash) | | API_EMAIL | Login email | | API_PASSWORD | Login password |

Strongly recommended

| Variable | Description | |---|---| | API_SWAGGER_URL | OpenAPI/Swagger JSON URL — enables fetch_spec, search_endpoints, and auto-login-endpoint discovery |

Optional

See Environment Variables Reference for the full list.

Tools

`search_endpoints`

Fuzzy-search the API spec by keyword. Returns matching endpoints with method, path, summary, tags, and required parameters. Use this before request when you don't know the exact path.

Input:

| Field | Type | Required | Description | |---|---|---|---| | query | string | ✅ | Keywords to search for | | limit | number | ❌ | Max results (default: 10) |

Example — Find order-related endpoints:

search_endpoints("orders list customer")

Response:

Found 6 match(es) for "orders list customer", showing top 5:

1. GET /customers/{id}/orders
   Summary: List all orders for a customer
   Tags: Orders, Customers
   Required params: path:id

2. GET /orders
   Summary: List orders with optional filters
   Tags: Orders
   Required params: query:status, query:page

3. POST /orders/search
   Summary: Search orders by multiple criteria
   Tags: Orders
   Required params: body
...

`describe_endpoint`

Returns the full OpenAPI schema for a single endpoint: parameters, request body schema (with types, required flags, enums, examples), response schemas, and a generated example request body. Use this before request() when you need to know exactly what fields to include in the body or what response shape to expect.

Input:

Example — Inspect a POST endpoint before calling it:

describe_endpoint("POST", "/pharmacy/add-manager")

Response:

{
  "method": "POST",
  "path": "/pharmacy/add-manager",
  "summary": "Add a manager to a pharmacy",
  "parameters": [
    { "name": "pharmacyId", "in": "path", "required": true, "type": "string" }
  ],
  "requestBody": {
    "contentType": "application/json",
    "schema": {
      "type": "object",
      "properties": {
        "first_name": { "type": "string", "required": true },
        "email": { "type": "string", "required": true },
        "gender": { "type": "string", "enum": ["male", "female"], "required": true },
        "start_date": { "type": "string", "format": "date-time", "required": true }
      }
    },
    "example": {
      "first_name": "First name",
      "email": "[email protected]",
      "gender": "male",
      "start_date": "2026-05-04T12:00:00Z"
    }
  },
  "responses": {
    "201": {
      "description": "Manager added successfully",
      "schema": { "type": "object", "properties": { "id": { "type": "number" } } },
      "example": { "id": 42 }
    }
  }
}

The AI can now call request() with the exact body shape, no guessing required.

`request`

Make an authenticated API call. Handles login automatically — re-logins transparently if the token is expired.

Input:

| Field | Type | Required | Description | |---|---|---|---| | method | string | ✅ | GET, POST, PUT, PATCH, DELETE | | endpoint | string | ✅ | Path relative to REST_BASE_URL, e.g. /users/profile | | body | object | ❌ | Request body for POST/PUT/PATCH | | headers | object | ❌ | Extra headers to merge | | skip_auth | boolean | ❌ | Set true to skip the Authorization header | | token_path | string | ❌ | Dot-notation path to the token in the login/verify response (e.g. data.result.accessToken). Overrides auto-detection and is cached for re-logins. | | verify_session_fields | object | ❌ | Map of verify-body field names → dot-notation paths in the step-1 login response. Example: {"sessionId": "data.result.sessionId"}. Overrides hardcoded candidates and is cached for re-logins. |

Response shape:

{
  "status": 200,
  "statusText": "OK",
  "timing_ms": 312,
  "login_data": { ... },
  "response": { ... }
}

login_data contains the full login response — useful for IDs like userId, orgId, tenantId returned at login that you need for subsequent requests.

Example — GET current user profile:

request("GET", "/users/me")

Example — POST with filters:

request("POST", "/orders/search", {
  "status": "pending",
  "from": "2025-01-01",
  "limit": 20
})

Example — PATCH to update a resource:

request("PATCH", "/products/42", {
  "price": 9.99,
  "inStock": true
})

Example — Public endpoint (no auth):

request("GET", "/health", skip_auth=true)

Example — Custom token path (when auto-detection fails):

request("GET", "/orders", token_path="result.data.jwtToken")

Example — Custom 2FA session fields:

request("GET", "/orders",
  token_path="data.result.accessToken",
  verify_session_fields={"sessionId": "data.result.sessionId", "requestToken": "data.result.requestToken"}
)

`inspect_login`

Performs the login flow (and optional 2FA verify) and returns the raw server responses without extracting a token. Also returns heuristic suggestions for:

Token paths (fields that look like JWTs or long auth strings)
Session fields (fields that look like session identifiers for 2FA verify)

Use this when auto-detection fails so the AI can identify the correct token_path and verify_session_fields to pass to request().

No input required.

Example — when request() fails with "Could not find token":

inspect_login()

Response:

{
  "step1": { "status": 200, "data": { "result": { "customJwt": "eyJ...", "sessionId": "abc" } } },
  "step2": null,
  "token_suggestions": [
    { "path": "result.customJwt", "value_preview": "eyJhbGciOiJIUzI1Ni...", "confidence": 4 }
  ],
  "session_field_suggestions": [
    { "path": "result.sessionId", "key": "sessionId", "value_preview": "abc" }
  ],
  "note": "Use token_path and verify_session_fields in your next request() call."
}

Then call request() with the AI-discovered path:

request("GET", "/orders", token_path="result.customJwt")

The server caches the AI-provided token_path and verify_session_fields so re-logins (after token expiry) use them automatically.

`fetch_spec`

Fetch the full OpenAPI/Swagger JSON spec for schema inspection, DTO discovery, or understanding available endpoints.

Input:

| Field | Type | Required | Description | |---|---|---|---| | url | string | ❌ | Override spec URL. Falls back to API_SWAGGER_URL env var |

Example:

fetch_spec()

Returns the raw OpenAPI JSON (truncated to REST_RESPONSE_SIZE_LIMIT if large).

Authentication Flows

Standard login

The most common case — email + password, token returned directly.

{
  "REST_BASE_URL": "https://api.example.com/api/v1",
  "API_EMAIL": "[email protected]",
  "API_PASSWORD": "secret",
  "API_SWAGGER_URL": "https://api.example.com/docs-json"
}

The server auto-discovers the login endpoint by scanning the Swagger spec for the first POST path containing "login". Override if needed:

"API_LOGIN_ENDPOINT": "/auth/sign-in"

Login with extra credentials

Some APIs require fields beyond email and password in the login request body — for example a role to specify what type of user is logging in, a source to indicate which client platform is making the request, a channel, a tenantId, etc.

Set API_LOGIN_CREDENTIALS to a JSON object string containing any extra fields you need. They are merged into the login POST body alongside email and password:

"API_LOGIN_CREDENTIALS": "{\"role\": \"admin\"}"

What gets sent to the login endpoint:

{
  "email": "[email protected]",
  "password": "secret",
  "role": "admin"
}

Multiple extra fields work the same way:

"API_LOGIN_CREDENTIALS": "{\"role\": \"viewer\", \"source\": \"web\", \"tenantId\": \"acme\"}"

What gets sent:

{
  "email": "[email protected]",
  "password": "secret",
  "role": "viewer",
  "source": "web",
  "tenantId": "acme"
}

Note: The field names are entirely up to your API. Check its Swagger spec or docs to see what the login endpoint accepts.

Two-factor authentication (2FA)

Some APIs require a second verification step after the initial login — the server returns a one-time code to the user's email or phone, and you must submit it to a separate endpoint to receive the actual JWT.

Flow:

Step 1 — Login
  POST /auth/login  { email, password }
  ← 200: { session_token: "tmp_abc", message: "OTP sent to email" }

Step 2 — Verify OTP
  POST /auth/verify-otp  { email, otp: "482019", session_token: "tmp_abc" }
  ← 200: { accessToken: "eyJhbGci..." }

The three env vars that drive this:

"API_VERIFY_ENDPOINT": "/auth/verify-otp",
"API_OTP": "482019",
"API_LOGIN_CREDENTIALS": "{\"platform\": \"web\"}"

API_VERIFY_ENDPOINT — The path of the second step. When this is set, the server automatically performs both steps before attaching a token to your request.

API_OTP — The OTP value to submit. For staging environments this is usually a fixed test code provided by the API team. For production you'd need to retrieve the live code from your email and set it here.

Session carry-forward — Session identifiers returned by login step 1 (e.g. session_token, requestId, temp_token, nonce, transactionId) are automatically detected and forwarded to the verify endpoint. You do not need to configure this manually.

The full body sent to the verify endpoint looks like:

{
  "email": "[email protected]",
  "otp": "482019",
  "session_token": "tmp_abc"   ← auto-carried from step 1
}

API_VERIFY_CREDENTIALS — If your verify endpoint requires extra fields that aren't session identifiers or the OTP, add them here:

"API_VERIFY_CREDENTIALS": "{\"client_id\": \"web-app\"}"

What gets sent:

{
  "email": "[email protected]",
  "otp": "482019",
  "session_token": "tmp_abc",
  "client_id": "web-app"    ← from API_VERIFY_CREDENTIALS
}

Multi-API Setup

Run multiple independent server instances — one per API — in the same mcp.json. Each instance runs its own auth session, token cache, and spec cache independently.

In this example, shop-api uses a simple role-based login and analytics-api uses 2FA:

{
  "servers": {
    "shop-api": {
      "command": "npx",
      "args": ["-y", "rest-api-mcp"],
      "env": {
        "REST_BASE_URL": "https://api.acme-shop.com/v1",
        "API_EMAIL": "[email protected]",
        "API_PASSWORD": "s3cr3t",
        "API_LOGIN_CREDENTIALS": "{\"role\": \"admin\"}",
        "API_SWAGGER_URL": "https://api.acme-shop.com/docs-json"
      }
    },
    "analytics-api": {
      "command": "npx",
      "args": ["-y", "rest-api-mcp"],
      "env": {
        "REST_BASE_URL": "https://analytics.acme.com/api/v2",
        "API_EMAIL": "[email protected]",
        "API_PASSWORD": "s3cr3t",
        "API_LOGIN_ENDPOINT": "/auth/sign-in",
        "API_VERIFY_ENDPOINT": "/auth/verify-otp",
        "API_OTP": "482019",
        "API_SWAGGER_URL": "https://analytics.acme.com/openapi.json"
      }
    }
  }
}

VS Code mcp.json Examples

Minimal

{
  "servers": {
    "my-api": {
      "command": "npx",
      "args": ["-y", "rest-api-mcp"],
      "env": {
        "REST_BASE_URL": "https://api.example.com/v1",
        "API_EMAIL": "[email protected]",
        "API_PASSWORD": "secret"
      }
    }
  }
}

Full (all options)

{
  "servers": {
    "my-api": {
      "command": "npx",
      "args": ["-y", "rest-api-mcp"],
      "env": {
        "REST_BASE_URL": "https://api.example.com/v1",
        "REST_ENABLE_SSL_VERIFY": "false",
        "REST_RESPONSE_SIZE_LIMIT": "150000",
        "API_EMAIL": "[email protected]",
        "API_PASSWORD": "secret",
        "API_LOGIN_ENDPOINT": "/auth/login",
        "API_LOGIN_CREDENTIALS": "{\"source\":\"mobile\"}",
        "API_VERIFY_ENDPOINT": "/auth/verify-otp",
        "API_OTP": "123456",
        "API_VERIFY_CREDENTIALS": "{\"device_id\":\"abc\"}",
        "API_TOKEN_PATH": "data.access_token",
        "API_SWAGGER_URL": "https://api.example.com/docs-json"
      }
    }
  }
}

How It Works

Agent says: "show me pending orders"
     │
     ▼
search_endpoints("orders pending list")
     │  Fetches Swagger spec, scores every endpoint by keyword match
     │  Returns: GET /orders  ← best match
     ▼
request("GET", "/orders?status=pending")
     │
     ├─ Token cache valid? ──yes──► attach Bearer token
     │
     └─ Cache expired/empty?
           │
           ├─ Step 1: POST /auth/login  {email, password, ...LOGIN_CREDENTIALS}
           │          ◄── 200: {data: {access_token: "eyJ..."}}
           │
           ├─ [if VERIFY_ENDPOINT set]
           │   Step 2: POST /auth/verify-otp  {email, otp, ...session_tokens}
           │            ◄── 200: {accessToken: "eyJ..."}
           │
           ├─ Auto-detect token path from response (or use AI-provided token_path)
           ├─ Cache token for 20s
           └─ attach Bearer token
     │
     ▼
GET /orders?status=pending
     Authorization: Bearer eyJ...
     ◄── 200: {total: 47, data: [{id: 1, status: "pending", ...}, ...]}

When auto-detection fails:

request("GET", "/orders")  ← "Could not find token"
     │
     ▼
inspect_login()
     │  Returns raw login response + token/session suggestions
     ▼
request("GET", "/orders", token_path="data.result.jwt")
     │  Token path cached for future re-logins
     ▼
✅ Success

Environment Variables Reference

| Variable | Required | Default | Description | |---|---|---|---| | REST_BASE_URL | ✅ | — | Base API URL, no trailing slash | | API_EMAIL | ✅* | — | Login email (required for authenticated endpoints) | | API_PASSWORD | ✅ | — | Login password | | API_SWAGGER_URL | — | — | OpenAPI JSON URL for fetch_spec, search_endpoints, and login auto-discovery | | API_LOGIN_ENDPOINT | — | auto-discovered | Override login path, e.g. /auth/sign-in | | API_LOGIN_CREDENTIALS | — | — | JSON object of extra fields merged into the login POST body alongside email/password. Use for role, source, tenantId, etc. Example: {"role":"admin"} | | API_VERIFY_ENDPOINT | — | — | Path of the 2FA/OTP verify step. Setting this enables two-step auth. Example: /auth/verify-otp | | API_OTP | — | — | The OTP code to submit to API_VERIFY_ENDPOINT. On staging this is typically a fixed test code. | | API_VERIFY_CREDENTIALS | — | — | JSON object of extra fields merged into the verify POST body, beyond the auto-carried session identifiers and OTP. Example: {"client_id":"web-app"} | | API_TOKEN_PATH | — | auto-detected | Dot-path to token in login/verify response, e.g. data.access_token | | REST_ENABLE_SSL_VERIFY | — | true | Set false to skip TLS cert validation (dev/staging only) | | REST_RESPONSE_SIZE_LIMIT | — | 100000 | Max response characters before truncation |

Auto-detected token paths (tried in order): data.access_token · access_token · data.token · token · data.accessToken · accessToken · data.data.access_token · result.access_token · result.token

If none match, use inspect_login() to discover the correct path and pass it via token_path.

Auto-forwarded session fields (2FA step 1 → step 2): session_token · sessionToken · session · request_id · requestId · temp_token · tempToken · verification_token · verificationToken · challenge · nonce · transaction_id · transactionId

Override these via verify_session_fields when the API uses non-standard session field names.

Troubleshooting

Login failed: Could not find token
The login response uses an unusual token path. Use inspect_login() to see the raw response and heuristic suggestions, then pass the correct path to request():

inspect_login()                    ← see suggestions
request("GET", "/orders", token_path="result.data.jwt")

Alternatively, set API_TOKEN_PATH explicitly in env:

"API_TOKEN_PATH": "result.data.jwt"

2FA verify fails with 401
The verify endpoint may need the OTP as a different field name. Use API_VERIFY_CREDENTIALS:

"API_VERIFY_CREDENTIALS": "{\"code\": \"123456\"}"

And leave API_OTP unset if the field name isn't otp.

search_endpoints returns no matches

Make sure API_SWAGGER_URL is set and reachable
Try broader keywords: "inventory" instead of "getInventory"
The spec may be truncated — use fetch_spec to check

SSL errors on staging

"REST_ENABLE_SSL_VERIFY": "false"

Response truncated
Increase the limit:

"REST_RESPONSE_SIZE_LIMIT": "500000"

License

MIT

Published

Vulnerabilities

Links

Maintainers

Keywords

Readme

rest-api-mcp

Table of Contents

Features

Installation

Option A — Use via npx (recommended)

Option B — Use locally (for development / offline)

Quick Start

Configuration

Minimum required

Strongly recommended

Optional

Tools

search_endpoints

describe_endpoint

request

inspect_login

fetch_spec

Authentication Flows

Standard login

Login with extra credentials

Two-factor authentication (2FA)

Multi-API Setup

VS Code mcp.json Examples

Minimal

Full (all options)

How It Works

Environment Variables Reference

Troubleshooting

License

`search_endpoints`

`describe_endpoint`

`request`

`inspect_login`

`fetch_spec`