HAPI Workflows (Arazzo) plugin

With the Enterprise A2A plugin installed, use hapi serve --specs ./workflow.arazzo.yaml --dry-run --a2a --output json to preview the read-only workflow Agent Card. The same command without --a2a retains the MCP tool preview. yaml, markdown, and table are also available. Arazzo serving does not currently expose Capability Graph planning tools; only compiled workflow skills appear in this card.

@mcp-com-ai/plugin-arazzo lets HAPI expose an Arazzo workflow as MCP tools. Each workflow can coordinate one or more API operations, while the APIs remain the source of business logic.

Install and serve

Install this plugin alongside the HAPI command:

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

Validate, then serve a local or remote Arazzo document:

hapi arazzo validate --specs ./workflow.yaml
hapi serve --specs ./workflow.yaml --headless --port 3000

Connect your MCP client to http://localhost:3000/mcp.

These commands are equivalent when this plugin is installed:

hapi serve --specs ./workflow.yaml --mcp
hapi arazzo serve --specs ./workflow.yaml --mcp
hapi workflows serve --specs ./workflow.yaml --mcp

workflows is an alias for arazzo. The short hapi serve --specs form detects Arazzo automatically and uses the same command shape as OpenAPI. The runtime supports sequential HTTP operations from OpenAPI sources; unsupported sources are rejected before serving.

The CLI installs Core and shared utilities automatically. Keep this plugin and @mcp-com-ai/hapi on the same release version.

Plan-only workflow transitions

A validated workflow can contribute one atomic transition to capability-graph planning by declaring workflow-level x-hapi-planning with requires, non-empty produces, optional removes, and a finite nonnegative cost. Eligibility is deliberately narrow: every step must resolve to OpenAPI, and the workflow cannot use nested workflows or dynamic success/failure control flow. Unsupported workflows still compile for ordinary execution but produce a planning diagnostic and no planning transition.

This metadata describes state change for simulation only. The capability planner never calls the Arazzo executor.

hapi arazzo validate also compares each planning-eligible workflow with the x-hapi-planning of the source operations its steps call. It applies the steps in order, removing facts before producing them, and prints a warning when the workflow's metadata disagrees with that net effect:

| Code | Meaning | | --- | --- | | ARAZZO_PLANNING_REQUIRES_INCOMPLETE | A step needs a fact from outside that the workflow does not require. | | ARAZZO_PLANNING_PRODUCES_INCOMPLETE | The steps leave a new fact that the workflow does not produce. Extra aggregate facts are allowed. | | ARAZZO_PLANNING_REMOVES_CONTRADICTS_STEPS | The workflow removes a fact that a later step re-establishes. | | ARAZZO_PLANNING_ANALYSIS_INCOMPLETE | A step's source operation has no valid x-hapi-planning, so no comparison is made. |

These are warnings. They do not change planning eligibility or the exit code, unless you pass --strict, which exits 1 when any planning diagnostic is reported:

hapi arazzo validate ./workflows.arazzo.yaml --strict