stacklok / toolhive / 19368769071

51%

Build Type

push

github

Committed by web-flow

Commit Message

Apply parameter defaults in composite tool workflows (#2588)

* Apply parameter defaults in composite tool workflows

Composite tool workflows can define parameter schemas with default
values, but these defaults were not being applied when clients called
the tool with missing parameters. This caused template expansion to
fail with "<no value>" when referencing undefined parameters.

This fix applies JSON Schema defaults before workflow execution:
- Extract default values from workflow parameter schema
- Apply defaults only for missing parameters
- Never override explicitly provided parameters

Example workflow with defaults:
```yaml
composite_tools:
  - name: "fetch_spec"
    parameters:
      base_url:
        type: "string"
        default: "https://spec.modelcontextprotocol.io"
    steps:
      - tool: "fetch"
        arguments:
          url: "{{.params.base_url}}/page"  # Now works with empty args
```

Changes:
- Add applyParameterDefaults() function to workflow engine
- Apply defaults before creating workflow context
- Add tests for default application and override behavior

Fixes template expansion failures when clients don't provide optional
parameters that have defaults defined in the workflow schema.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* apply fix for recommendation from review

Signed-off-by: Juan Antonio Osorio <ozz@stacklok.com>

---------

Signed-off-by: Juan Antonio Osorio <ozz@stacklok.com>
Co-authored-by: Claude <noreply@anthropic.com>

Run Details

27 of 29 new or added lines in 1 file covered. (93.1%)

4 existing lines in 1 file now uncovered.

23251 of 48209 relevant lines covered (48.23%)

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