Add built-in Serena MCP support with language service integration and Go configuration options #4610

Copilot · 2025-11-23T19:00:55Z

Adds native Serena MCP support following the Playwright integration pattern. Enables language-specific code analysis through automatic runtime detection and language server installation.

Syntax

Short form:

tools:
  serena: ["go", "typescript"]

Full configuration:

tools:
  serena:
    version: latest
    args: ["--verbose"]
    languages:
      go:
        version: "1.21"
        go-mod-file: "backend/go.mod"
        gopls-version: "v0.14.2"
      typescript:
      python:
        version: "3.12"

Implementation

Schema & Types

Added JSON schema supporting both array and object syntax for 6 languages (go, typescript, python, java, rust, csharp)
Added SerenaToolConfig struct with per-language version configuration
Implemented dual-syntax parser in parseSerenaTool()
Added Go-specific configuration fields: go-mod-file and gopls-version

MCP Rendering

Generates uvx --from git+https://github.com/oraios/serena serena start-mcp-server --context codex --project ${{ github.workspace }}
Appends custom args when specified
Integrated across all engines (Copilot, Claude, Codex, Custom)

Runtime Integration

detectSerenaLanguages() maps languages to runtime requirements (Go → go, TypeScript → node, Python → python)
Enhanced Go runtime detection to support custom go.mod file paths and explicit version configuration
GenerateSerenaLanguageServiceSteps() installs language servers:
- Go: go install golang.org/x/tools/gopls@<version> (configurable version)
- TypeScript: npm install -g typescript-language-server typescript
- Python: pip install python-lsp-server
- Rust: rustup component add rust-analyzer
Steps injected after runtime setup in compiler

Go Configuration Options

version: Explicitly set Go version (e.g., "1.21", 1.21)
go-mod-file: Specify path to go.mod file for version detection (e.g., "backend/go.mod")
- Default: "go.mod"
- Useful for monorepos with Go modules in subdirectories
gopls-version: Specify gopls version to install (e.g., "latest", "v0.14.2")
- Default: "latest"

Validation

Added "serena" to standard MCP tools list in mcp_servers.go
Skip built-in tools in ValidateMCPConfigs() to prevent custom MCP schema conflicts

Smoke Test Integration

Added serena: ["go"] to all smoke test workflows for continuous validation:
- smoke-copilot.md - Tests Serena with Copilot engine
- smoke-claude.md - Tests Serena with Claude engine
- smoke-codex.md - Tests Serena with Codex engine
Each smoke test now verifies Serena MCP functionality, Go runtime setup, and gopls installation

Files Changed

Schema: main_workflow_schema.json
Types: tools_types.go, args.go
Rendering: mcp-config.go, mcp_renderer.go
Engines: copilot_engine.go, claude_mcp.go, codex_engine.go, custom_engine.go
Runtime: runtime_setup.go, compiler_yaml.go
Validation: mcp_config_validation.go, mcp_servers.go
Demo: dev.md, test workflows
Smoke Tests: smoke-copilot.md, smoke-claude.md, smoke-codex.md
Test Workflows: test-serena-go-config.md, test-serena-custom-gomod.md, updated test-serena-long.md

Original prompt

Add builtin support for the Serena MCP in the "tools" frontmatter section, similarly to the playwright support.

added to schema and added compiler support

allows selection and configuration of each language

integration with runtime system to install runtime dependencies steps

Syntax: short

tools:
serena: ["go"]

Longer with options

tools:
serena:
version: ... # MCP version
args: ["..."] # custom arguments to MCP
languages:
go:
version: ... # go tooling version
typescript: # empty key supported

Update dev.md to use this feature as a test.

see Serena shared agentic workflow for code pattern to invoke MCP

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

…ntime integration Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2025-11-23T19:51:48Z

@copilot add serena with go all smoke agentic workflows

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2025-11-23T19:59:51Z

@copilot add serena with go all smoke agentic workflows

Added serena: ["go"] to all three smoke test workflows (smoke-copilot, smoke-claude, and smoke-codex). Each workflow now includes:

Serena MCP configuration with uvx
Go runtime setup
gopls language service installation

Commit: 190207f

pelikhan · 2025-11-23T20:34:38Z

@copilot for go, allow configuring the go version, go.mod file location and the gopls version

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2025-11-23T20:48:54Z

@copilot for go, allow configuring the go version, go.mod file location and the gopls version

Added Go configuration options to Serena:

Fields:

version: Go version (e.g., "1.21", 1.21)
go-mod-file: Path to go.mod file (e.g., "backend/go.mod")
gopls-version: gopls version (e.g., "latest", "v0.14.2")

Example:

tools:
  serena:
    languages:
      go:
        version: "1.21"
        go-mod-file: "backend/go.mod"
        gopls-version: "v0.14.2"

Generated steps:

Go setup uses go-version-file: backend/go.mod when go-mod-file is specified
gopls installation uses go install golang.org/x/tools/gopls@v0.14.2

All three test workflows created and verified:

test-serena-go-config.md (all options)
test-serena-custom-gomod.md (custom path)
test-serena-long.md (updated with new options)

Commit: 6872bb5

github-actions · 2025-11-23T20:53:46Z

✅ Agentic Changeset Generator completed successfully.

Copilot

Pull request overview

This PR adds native Serena MCP support following the Playwright integration pattern. It enables language-specific code analysis through automatic runtime detection and language server installation.

Key features:

Dual syntax support: short form (array) and full configuration (object)
6 supported languages: Go, TypeScript, Python, Java, Rust, C#
Go-specific configuration: custom go.mod path and gopls version
Automatic runtime detection and language service installation
Integration across all engines (Copilot, Claude, Codex, Custom)

Main concerns:

Duplicate arguments in MCP config generation causing command duplication
Unrelated whitespace changes mixed into the PR
Potential missing import issue in tools_types.go

Reviewed changes

Copilot reviewed 41 out of 43 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
pkg/workflow/tools_types.go	Adds SerenaToolConfig struct and parsing logic with dual-syntax support
pkg/workflow/runtime_setup.go	Implements language detection and language service installation steps
pkg/workflow/mcp_servers.go	Adds "serena" to standard MCP tools list
pkg/workflow/mcp_renderer.go	Adds Serena MCP rendering for all engines
pkg/workflow/mcp-config.go	Implements Serena MCP config generation with engine-specific options
pkg/workflow/compiler_yaml.go	Integrates Serena language service steps into compilation
pkg/parser/schemas/main_workflow_schema.json	Adds comprehensive JSON schema for Serena configuration
.github/workflows/smoke-*.md	Adds Serena to smoke tests for continuous validation
.github/workflows/test-serena-*.md	New test workflows for various Serena configurations
.github/workflows/*.lock.yml	Generated lock files showing MCP config (with duplicate args bug)

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2025-11-23T21:07:37Z

.github/workflows/typist.lock.yml

+                  "--from",
+                  "git+https://github.com/oraios/serena",
+                  "serena",
+                  "start-mcp-server",
+                  "--context",
+                  "codex",
+                  "--project",
+                  "${{ github.workspace }}",


The MCP configuration is generating duplicate arguments. The args array contains the full command sequence twice:

"--from", "git+https://github.com/oraios/serena", "serena", "start-mcp-server", "--context", "codex", "--project", "${{ github.workspace }}"

This pattern appears twice in the args array, which will cause the command to fail or behave incorrectly. This appears to be happening in multiple generated lock files (typist.lock.yml, semantic-function-refactor.lock.yml, repository-quality-improver.lock.yml, etc.).

See below for a potential fix:

Copilot · 2025-11-23T21:07:37Z

pkg/workflow/js/safe_output_validator.test.cjs

+
    // Reset mock implementations to default
    mockExistsSync.mockReturnValue(false);
    mockReadFileSync.mockReturnValue("");
-    
+


[nitpick] Inconsistent whitespace: There are extra blank lines being removed (lines 35 and 39 in the diff) that are unrelated to the Serena functionality being added. These formatting changes should be in a separate commit or reverted to keep the PR focused on the Serena feature.

Copilot · 2025-11-23T21:07:37Z

pkg/workflow/tools_types.go

+	"fmt"
+


Missing import: The fmt package is imported but this file was already using fmt.Sprintf in existing code (line 513 in the diff), so the import should have already existed. However, if this is a new file or the import was previously missing, this is correct. Please verify that the existing code compiles without this import or if this import is actually needed for the new code.

Initial plan

799db1d

Copilot AI assigned Copilot and pelikhan Nov 23, 2025

Copilot started work on behalf of pelikhan November 23, 2025 19:01 View session

Copilot AI and others added 3 commits November 23, 2025 19:31

Add built-in Serena MCP support with schema, types, rendering, and ru…

896569e

…ntime integration Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Complete Serena MCP integration: fix MCP tool detection and validation

c5e0cf8

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Remove unused renderSerenaMCPConfig function to pass linter

abc62a1

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add builtin support for the Serena MCP in tools section~~ Add built-in Serena MCP support with language service integration Nov 23, 2025

Copilot finished work on behalf of pelikhan November 23, 2025 19:49

Copilot AI requested a review from pelikhan November 23, 2025 19:49

Copilot started work on behalf of pelikhan November 23, 2025 19:52 View session

Add serena with go to all smoke test workflows

190207f

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan November 23, 2025 20:01

Copilot started work on behalf of pelikhan November 23, 2025 20:35 View session

Add Go configuration options: go-version, go-mod-file, and gopls-version

6872bb5

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~Add built-in Serena MCP support with language service integration~~ Add built-in Serena MCP support with language service integration and Go configuration options Nov 23, 2025

Copilot finished work on behalf of pelikhan November 23, 2025 20:50

pelikhan added the smoke label Nov 23, 2025

Add changeset [skip-ci]

bba3b3f

pelikhan marked this pull request as ready for review November 23, 2025 21:04

Copilot AI review requested due to automatic review settings November 23, 2025 21:04

pelikhan merged commit 7569987 into main Nov 23, 2025
17 checks passed

pelikhan deleted the copilot/add-serena-mcp-support branch November 23, 2025 21:04

Copilot started reviewing on behalf of pelikhan November 23, 2025 21:05 View session

Copilot finished reviewing on behalf of pelikhan November 23, 2025 21:06

Copilot AI reviewed Nov 23, 2025

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Add built-in Serena MCP support with language service integration and Go configuration options #4610

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Add built-in Serena MCP support with language service integration and Go configuration options #4610

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Syntax

Implementation

Schema & Types

MCP Rendering

Runtime Integration

Go Configuration Options

Validation

Smoke Test Integration

Files Changed

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Pull request overview

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