triggerBuild: List Git Branches Parameter (TAG) not applied — only core parameters appear in ParametersAction

[dierbei]

What feature do you want to see added?

### Jenkins / plugins

- **Jenkins**: 2.541.2
- **MCP Server plugin**: MCP Server Plugin 0.158.v8e18e64dd93c
- **List Git Branches Parameter plugin** : List Git Branches Parameter PlugIn 0.0.13

### Summary

When calling the MCP tool `triggerBuild` with a `parameters` map that includes the **List Git Branches** parameter (e.g. `TAG`), the build is queued successfully, but the resulting run’s `ParametersAction` **does not contain** that parameter. Only parameters that map to “core” types (e.g. `StringParameterValue` for choice, `BooleanParameterValue`) appear.

This contradicts the [plugin documentation](https://plugins.jenkins.io/mcp-server/) stating that *Plugin Parameters* are *automatically detected and handled* and that unsupported parameters *fall back to defaults with logging* — in our case `TAG` seems to be dropped silently (no `ListGitBranchesParameterValue` in the build).

### Job configuration (high level)

- Job type: **Pipeline** (`WorkflowJob`), parameterized.
- Parameters include:
  - `APP_ENV` — **Choice**
  - `TAG` — **List Git Branches (and more)** (`PT_BRANCH_TAG` / `ListGitBranchesParameterDefinition`)
  - `BUILD_ONLY`, `ROLLBACK` — **Boolean**

### Steps to reproduce

1. Create or use a parameterized pipeline job with a **List Git Branches Parameter** named e.g. `TAG`.
2. Call MCP `triggerBuild` with JSON similar to:

```json
{
  "jobFullName": "<folder>/<job>",
  "parameters": {
    "APP_ENV": "qa1",
    "TAG": "refs/heads/FEATURE-EFF-xxxxxxx",
    "BUILD_ONLY": false,
    "ROLLBACK": false
  }
}

3. Open the queued run (or query REST/API .../api/json?tree=actions[parameters[name,value,_class]]).
4. Inspect actions → ParametersAction → parameters.

Expected behavior

• The build should record a parameter value for TAG (e.g. ListGitBranchesParameterValue or equivalent), matching the string passed in parameters.TAG, consistent with Build with Parameters in the UI and with POST .../buildWithParameters (form field TAG=...).

Actual behavior

• triggerBuild returns success and the build runs, but TAG is missing from ParametersAction.
• Observed parameters on the run: only APP_ENV, BUILD_ONLY, ROLLBACK.
• Queue item params string also omits TAG (only the three above).

Additional context

• Direct REST POST .../buildWithParameters with application/x-www-form-urlencoded including TAG=... works and the run shows the branch/tag parameter correctly.
• This suggests the MCP server path is not forwarding or not constructing the plugin-specific parameter value for List Git Branches Parameter, while core types work.

Suggested direction

• Ensure triggerBuild builds the same parameter set as buildWithParameters for all ParameterDefinition types registered on the job, including third-party List Git Branches / PT_BRANCH_TAG.
• If a parameter cannot be mapped, log explicitly (per docs: Comprehensive logging for debugging parameter issues) instead of silently omitting.

Thank you for looking into this.

Upstream changes

No response

Are you interested in contributing this feature?

No response

[donhui]

The issue has been resloved by pr #170 .