CAPI Gateway — MCP server for Claude Code: REST to MCP
Turns an existing REST API into an MCP tool with no changes on the backend. Register the service in Consul and the agent sees its tools right away.
claude mcp add capi-gateway -- docker run -i --rm docker.io/surisoft/capi-core:1.417.5What CAPI Gateway does
CAPI Gateway is an API gateway built on Undertow's async proxy. Its MCP Gateway exposes services to LLM agents as tools, while your backends stay plain REST. CAPI reads the Consul metadata, builds the tool catalog, and translates a tools/call request into an HTTP call to your API. The reply comes back wrapped in MCP format.
Real MCP servers work too. Register one with mcp-type: server, and CAPI pulls its tools through tools/list and proxies calls to it. Both kinds of backend land under a single MCP endpoint. The MCP Gateway itself is marked experimental, same as the gRPC one.
You can run it from a JAR, Docker, or a Helm chart. The CAPI_CONFIG_FILE environment variable must point at a config file, otherwise the server won't start. The MCP port is 8383 (capi.mcp.port). Installing into an agent takes Docker, since the command launches the docker.io/surisoft/capi-core:1.417.5 image interactively.
What it helps with
- expose an existing REST API to an agent without rewriting the backend
- build a tool catalog from services registered in Consul
- proxy MCP server calls through one shared endpoint
- inspect routes and metrics through the Admin API
- validate OAuth2/OIDC tokens before hitting the backend
Example prompts for the agent
- List the tools CAPI Gateway exposes
- Call a tool through CAPI and show me the backend response
- Register a new service in Consul with MCP metadata
How to install CAPI Gateway
Platform CLI
claude mcp add capi-gateway -- docker run -i --rm docker.io/surisoft/capi-core:1.417.5Platform CLI
codex mcp add capi-gateway -- docker run -i --rm docker.io/surisoft/capi-core:1.417.5Config file
{
"mcpServers": {
"capi-gateway": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"docker.io/surisoft/capi-core:1.417.5"
]
}
}
}Config file
{
"servers": {
"capi-gateway": {
"type": "stdio",
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"docker.io/surisoft/capi-core:1.417.5"
]
}
}
}Platform CLI
gemini mcp add capi-gateway docker run -i --rm docker.io/surisoft/capi-core:1.417.5Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about CAPI Gateway
How do I install CAPI Gateway in Claude Code?
With one command: claude mcp add capi-gateway -- docker run -i --rm docker.io/surisoft/capi-core:1.417.5. Docker has to be available on the machine.
What does CAPI Gateway do?
It is an API gateway that presents REST services and MCP servers as MCP tools for LLM agents. The gateway handles the translation to JSON-RPC 2.0, so backends stay as they are.
What does the gateway need to run?
The CAPI_CONFIG_FILE environment variable pointing to a config file. Without it CAPI won't start.
