Add daily language support testing workflow for Go and TypeScript

[Copilot]

Automated daily validation of Go and TypeScript/JavaScript language server functionality via Serena MCP server (ghcr.io/github/serena-mcp-server:latest). Creates tracked issues on failure.

Implementation

• .github/agentics/language-support-tester.md: Agent prompt testing activate_project, symbol resolution, and language server responses for both languages
• .github/workflows/language-support-tester.md: Workflow config with daily fuzzy schedule, safe-outputs for issue creation, 7d issue expiration
• .github/workflows/language-support-tester.lock.yml: Compiled GitHub Actions workflow

Technical details

• Uses serena: ["go", "typescript"] (TypeScript identifier covers JavaScript files)
• Tests Go against /workspace/internal/ and TypeScript against /workspace/test/serena-mcp-tests/samples/js_project/
• Strict mode compliant: read-only permissions with safe-outputs for write operations
• Runtime-import pattern enables prompt iteration without recompilation
• Issues tagged language-support, serena-mcp, automation with [language-support] prefix

Example workflow structure

tools:
  serena: ["go", "typescript"]
  github:
    toolsets: [default]
safe-outputs:
  create-issue:
    title-prefix: "[language-support] "
    labels: [language-support, serena-mcp, automation]
    expires: 7d

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Pull request overview

This PR adds automated daily validation of Go and TypeScript/JavaScript language server functionality via the Serena MCP server (ghcr.io/github/serena-mcp-server:latest). The workflow runs daily at 02:50 UTC and creates tracked GitHub issues upon failure.

Changes:

• Introduces a new daily testing workflow for language support validation
• Tests both Go and TypeScript/JavaScript language server functionality via Serena MCP server
• Implements safe-outputs pattern for automated issue creation with 7-day expiration
• Uses runtime-import pattern to allow prompt iteration without workflow recompilation

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
.github/workflows/language-support-tester.md	Workflow configuration defining schedule, tools (Serena for go/typescript, GitHub), safe-outputs for issue creation, and runtime import of agent prompt
.github/workflows/language-support-tester.lock.yml	Compiled GitHub Actions workflow with complete job definitions, MCP gateway setup, Serena MCP server configuration, and safe-outputs processing
.github/agentics/language-support-tester.md	Agent prompt with instructions to test Go (in /workspace/internal/) and TypeScript/JavaScript (in /workspace/test/serena-mcp-tests/samples/js_project/) language support and create issues on failure

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[Copilot]

The safe-outputs configuration specifies that the create-issue tool will automatically add labels [language-support serena-mcp automation], but line 44 in the agent prompt instructs the agent to manually tag issues with labels language-support and serena-mcp. This is redundant since these labels are automatically added by the safe-outputs configuration. The instruction should be updated to clarify that these labels will be added automatically, or the agent should only be instructed to add any additional labels beyond those three if needed.

Suggested change

	- Tag with label: `language-support` and `serena-mcp`
	- Note: the `create-issue` safe output will automatically add the `language-support`, `serena-mcp`, and `automation` labels; add any additional labels only if needed