Rexi MCP Server

An MCP (Model Context Protocol) server that wraps the Rexi API and exposes tools and resources for AI assistants.

Features

Tools

• list_endpoints(tag: Optional[str]) – Lists all API endpoints discovered from docs/openapi.generated.yaml, optionally filtered by tag.

• call_rexi(...) – Generic caller for any Rexi API endpoint with full parameter support:

  • method: HTTP method (GET, POST, PUT, PATCH, DELETE, etc.)

  • path: API path (e.g., /v1/contracts/{contract_address})

  • path_params: Dictionary to substitute {placeholders} in the path

  • query: Query parameters as key-value pairs

  • body: Request body (sent as JSON)

  • extra_headers: Additional HTTP headers

  • timeout_seconds: Request timeout (default: 30s)

Resources

• rexi://openapi – Raw OpenAPI YAML specification

• rexi://routes – JSON summary of all methods, paths, summaries, and tags

• rexi://schemas – JSON array of available schema filenames

• rexi-schemas://{name} – Contents of a specific schema file from schema/ directory

Requirements

• Python 3.10+

• Dependencies: Install via pip install -r requirements.txt

  • mcp[cli] – MCP SDK with CLI tools

  • httpx – Async HTTP client

  • PyYAML – YAML parser for OpenAPI spec

  • python-dotenv – Environment variable management

• Rexi API Key (optional but recommended): Set via REXI_API_KEY environment variable

Environment Setup

Create a .env file in the project root (see .env.example):

REXI_API_KEY=your_api_key_here

Environment variables are loaded automatically when the server starts.

Running with the MCP CLI (Inspector)

From the project root:

uv run mcp dev mcp/server.py
# or with pipx / pip if you installed the CLI another way:
# mcp dev mcp/server.py

This opens the MCP Inspector to interactively test tools and resources.

Install into Claude Desktop (or other hosts)

uv run mcp install mcp/server.py \
  -v REXI_API_KEY=your_api_key_here

You can also pass -f .env to load environment variables from a file.

Configuration

The server determines the base URL from the OpenAPI spec servers[0].url. If not found, it defaults to https://api.rexi.sh.

• Auth header: x-api-key populated from REXI_API_KEY env var if present.

• OpenAPI file path: docs/openapi.generated.yaml.

• Schema directory: schema/.

Notes

• When calling call_rexi, supply any required path_params to fill placeholders like {contract_address} in the path you pass.

• query and body are sent as query parameters and JSON body respectively.

• The server validates nothing beyond basic substitution; refer to the schemas under schema/ for expected shapes.

• All context parameters (ctx) are automatically injected by FastMCP - you don't need to pass them manually.

Troubleshooting

Import Errors

If you get import errors for mcp, ensure you've installed the dependencies:

pip install -r requirements.txt

API Key Issues

If API calls fail with authentication errors, verify your REXI_API_KEY is set correctly in your .env file or environment.

Missing OpenAPI/Schema Files

The server gracefully handles missing docs/openapi.generated.yaml and schema/ directory. If these files are missing:

• list_endpoints() will return an empty list

• Resources will return appropriate error messages

• The server will still start and run