hloiseau/mcp-gopls

A Model Context Protocol (MCP) server that lets AI assistants use Go’s LSP (gopls) for navigation, diagnostics, testing, coverage, and more.
> **TL;DR:** If you use Claude / Cursor / Copilot with Go, mcp-gopls gives the AI full LSP powers:
> go-to-definition, references, hover, completion, go test, coverage, go mod tidy, govulncheck, etc.
Overview
This MCP server helps AI assistants to:
- Use LSP to analyze Go workspaces
- Navigate to definitions, references, and workspace symbols
- Format, rename, and inspect code actions without leaving MCP
- Run Go tests, coverage, go mod tidy, govulncheck, and module graph commands with structured results
- Read workspace resources (overview + go.mod) and consume curated prompts
> **Status:** Actively developed – used in real projects.
> Tested with Go 1.25.x and gopls@latest.
Architecture
This project uses the mark3labs/mcp-go library to implement the Model Context Protocol. The MCP integration enables seamless communication between AI assistants and Go tools.
The server communicates with gopls, the official language server for Go, via the Language Server Protocol (LSP).
Features
- **Configurable runtime**: --workspace, --gopls-path, --log-level, --rpc-timeout, and --shutdown-timeout flags + env vars (MCP_GOPLS_*)
- **Structured logging**: Text/JSON logging with slog and optional file output
- **Extended LSP surface**: navigation, diagnostics, formatting, rename, code actions, hover, completion, workspace symbols
- **Test & tooling helpers**: coverage analysis, go test, go mod tidy, govulncheck, go mod graph
- **MCP extras**: resources (resource://workspace/overview, resource://workspace/go.mod) and prompts (summarize_diagnostics, refactor_plan)
- **Progress streaming**: long-running commands emit notifications/progress events so clients can surface status updates
Feature comparison: mcp-gopls vs built-in gopls MCP
As of gopls v0.20.0, the built-in MCP server exposes these tools:
go_context, go_diagnostics, go_file_context, go_file_diagnostics,
go_file_metadata, go_package_api, go_references, go_rename_symbol,
go_search, go_symbol_references, go_workspace, go_vulncheck.
| Feature / capability | mcp-gopls (this project) | Built-in gopls MCP |
|----------------------|----------------------------|----------------------|
| Go-to-definition | Yes (go_to_definition tool) | No dedicated MCP tool (not in tool list) |
| Find references | Yes (find_references) | Yes (go_references, go_symbol_references) |
| Diagnostics (file / workspace) | Yes (check_diagnostics) | Yes (go_diagnostics, go_file_diagnostics) |
| Hover information | Yes (get_hover_info) | No dedicated MCP tool (not in tool list) |
| Completion | Yes (get_completion) | No dedicated MCP tool (not in tool list) |
| Formatting | Yes (format_document) | No dedicated MCP tool (not in tool list) |
| Rename symbol | Yes (rename_symbol) | Yes (go_rename_symbol) |
| Code actions | Yes (list_code_actions) | No dedicated MCP tool (not in tool list) |
| Workspace symbol search | Yes (search_workspace_symbols) | Yes (go_search) |
| Package / workspace API/context tools | No dedicated MCP tool | Yes (go_package_api, go_file_context, go_file_metadata, go_workspace, go_context) |
| Run go test | Yes (run_go_test) | No MCP tool for running tests |
| Coverage analysis | Yes (analyze_coverage) | No MCP tool for coverage |
| go mod tidy | Yes (run_go_mod_tidy) | No MCP tool for go mod tidy |
| govulncheck | Yes (run_govulncheck) | Yes (go_vulncheck) |
| Module graph (go mod graph) | Yes (module_graph) | No MCP tool for module graph |
| Extra MCP resources | Yes (resource://workspace/overview, resource://workspace/go.mod) | Not documented as MCP resources |
| Custom MCP prompts | Yes (summarize_diagnostics, refactor_plan) | Not exposed as MCP prompts (only model instructions) |
| Model instructions shipped with server | No special mechanism (documented in README/docs) | Yes: gopls mcp -instructions prints usage workflows |
If you want full LSP-like editing + tooling from MCP (definition, hover, completion, format, rename, code actions, go test, coverage, go mod tidy, module graph), mcp-gopls is strictly richer.