HAPI MCP

Turn an OpenAPI-described API into an MCP server, or expose an Arazzo workflow as a higher-level MCP tool.

This is the public distribution repository for HAPI binaries, packages, and end-user release artifacts. HAPI is a La Rebelion Labs product, alongside mcp.com.ai, clawne.me, and rebelion.la.

HAPI v1 beta

HAPI v1 is a major upgrade from the production-ready HAPI MCP 0.x release line, which remains available in the legacy repository. Version 1 adds a plugin-based CLI and introduces HAPI Workflows: Arazzo workflows served as MCP tools.

Use v1 beta releases for evaluation and integration testing. Keep using the 0.x latest Docker tag for production workloads until v1 reaches stable release. Pin a 1.0.0-beta.* version whenever repeatability matters.

Related MCP server: MCP from API

How it works

OpenAPI document ──> HAPI ──> one MCP tool per API operation

Arazzo document ───> HAPI ──> one MCP tool per workflowId
                                └─ workflow steps call their documented APIs

With OpenAPI, an operation such as getPet becomes an MCP tool. HAPI can proxy to an existing backend, so your API remains the source of truth for its business logic, authentication, and data.

With HAPI Workflows, an Arazzo workflowId becomes an MCP tool. A workflow can coordinate multiple documented OpenAPI operations—such as finding a provider, checking availability, and booking an appointment—behind one intentional tool call.

Choose an installation

Docker — recommended for trying HAPI v1

The workflows and arazzo tags point to the same HAPI v1 beta image.

docker pull hapimcp/hapi-cli:workflows
docker run --rm hapimcp/hapi-cli:workflows version

Use a pinned version instead of a moving tag in CI or shared environments:

docker pull hapimcp/hapi-cli:1.0.0-beta.0823

Packages

Install the CLI and the document plugins you want to use:

bun add -g @mcp-com-ai/hapi @mcp-com-ai/plugin-openapi @mcp-com-ai/plugin-arazzo

# npm also works
npm install -g @mcp-com-ai/hapi @mcp-com-ai/plugin-openapi @mcp-com-ai/plugin-arazzo

Confirm the installed capabilities:

hapi version
hapi plugins list
hapi doctor

Native binaries

Install the HAPI MCP CLI in one line, try MCP for your APIs in 5 seconds

Linux / macOS

curl -fsSL https://get.mcp.com.ai/hapi.sh | bash -s -- --version v1

Windows

irm https://get.mcp.com.ai/hapi.ps1 | iex -Version v1

Manual installation

Download the binary for your operating system from Releases, make it executable, and place it on your PATH. Linux releases include portable baseline and musl variants; prefer the baseline or musl-baseline variant when CPU compatibility is more important than maximum optimization.

Verify the accompanying checksum before executing a downloaded binary:

sha256sum -c <artifact>.sha256

Quick start: OpenAPI to MCP

Serve a local OpenAPI document and proxy MCP tool calls to its backend:

hapi openapi serve --specs ./openapi.yaml \
  --url https://api.example.com \
  --headless \
  --port 3000

The MCP endpoint is http://localhost:3000/mcp.

--specs accepts a local path, a file: or path: URL, an HTTP(S) URL, or a document stored under $HAPI_HOME/specs. If --url is omitted, HAPI uses the server URL declared in the OpenAPI document.

# Let HAPI detect an OpenAPI document automatically
hapi serve --specs https://api.example.com/openapi.yaml --port 3000

Quick start: HAPI Workflows (Arazzo)

Validate first, then serve an Arazzo document:

hapi workflows validate --specs ./workflow.yaml

hapi workflows serve --specs ./workflow.yaml \
  --port 3000 \
  --host 0.0.0.0 \
  --public-host http://localhost:3000

hapi arazzo serve and hapi workflows serve are exact aliases. The general hapi serve command also detects an Arazzo document automatically.

By default, each workflow step uses the server URL from the OpenAPI document referenced by its Arazzo sourceDescription. This supports workflows that coordinate multiple APIs. Use --url https://staging.example.com only when every step should use the same replacement backend.

Run a workflow with Docker

docker run --name hapi-workflows --rm -d \
  -p 3000:3000 \
  -v "$PWD:/specs:ro" \
  hapimcp/hapi-cli:workflows \
  workflows serve --specs /specs/workflow.yaml \
  --port 3000 \
  --host 0.0.0.0 \
  --public-host http://localhost:3000

--host 0.0.0.0 is required for a server that must be reached through Docker port publishing.

Useful commands

Run hapi help or append --help to a command to see every option.

Documentation and support

• HAPI documentation

• HAPI Workflows guide

• Docker deployment guide

• Report an issue or start a discussion

License

HAPI MCP is distributed under the La Rebelion Labs Community License.