GitlabMCPSharp

A standalone C# MCP (Model Context Protocol) server for GitLab (gitlab.com and self-hosted) over Streamable HTTP.

Features

• HTTP MCP server using the Streamable HTTP transport.
• Read-only mode by default — write/delete tools stay disabled until explicitly enabled.
• Project / group allow/deny lists and per-feature toggles (issues / merge requests / repository / pipelines / releases / groups / snippets).
• Configuration via GitlabMCPSharp.json, environment variables, or command line.
• Serilog logging to console and rolling files (daily + 50 MB rollover, 14-file retention).
• Runs as a console app or as a Windows Service.

Configuration

Configure via GitlabMCPSharp.json or environment variables. Environment variables win over JSON; in Docker, use the GITLABMCP_ prefix and __ for nested keys.

Setting	Default	Description
Gitlab:ApiBaseUrl	https://gitlab.com	Override for self-hosted GitLab (https://gitlab.example.com)
Gitlab:PersonalAccessToken	(none)	PAT with scope read_api (or api for writes)
Gitlab:OAuth2Token	(none)	Optional OAuth2 token used in place of a PAT
Gitlab:DefaultNamespace	(none)	Default group used when tools omit one
Gitlab:DefaultProject	(none)	Default project (group/project) used when tools omit one
Gitlab:UserAgent	GitlabMCPSharp	UA header sent to GitLab
Gitlab:ReadOnly	true	When true, all write/delete tools are disabled
Gitlab:DefaultPageSize	30	Page size for list operations (max 100)
Gitlab:MaxPages	5	Max pages traversed when paginating
Gitlab:RequestTimeoutSeconds	100	HTTP timeout
Gitlab:AllowedProjects	[]	Allow-list of group/project. Empty = no restriction
Gitlab:BlockedProjects	[]	Deny-list of group/project
Gitlab:AllowedGroups	[]	Allow-list of group full paths
Gitlab:EnableIssues / EnableMergeRequests / EnableRepository / EnablePipelines / EnableReleases / EnableGroups / EnableSnippets	true	Per-feature tool toggles
Gitlab:AcceptInvalidCertificates	false	Accept self-signed TLS certs (self-hosted only)
Server:Host	localhost	Host to bind
Server:Port	5702	HTTP port
Server:Path	/mcp	MCP endpoint path
Server:WindowsServiceName	GitlabMCPSharp	Service name when running under SCM
Server:Password	blank	Optional MCP endpoint password; blank disables password auth

When Server:Password is set, MCP requests must provide the password as Authorization: Bearer <password>, the Basic auth password, or X-MCP-Password.

Arrays use numeric indexes, for example GITLABMCP_Gitlab__AllowedProjects__0=group/project. Booleans use true or false.

Running

dotnet run

Then point your MCP client at http://localhost:5702/mcp.

Docker

Tagged releases publish a multi-architecture image for linux/amd64 and linux/arm64 to GitHub Container Registry:

docker run --rm -p 5702:5702 \
  -e GITLABMCP_Gitlab__ApiBaseUrl=https://gitlab.example.com \
  -e GITLABMCP_Gitlab__PersonalAccessToken=your-token \
  -e GITLABMCP_Gitlab__AllowedProjects__0=group/project \
  -e GITLABMCP_Server__Password=change-me \
  ghcr.io/wixely/gitlabmcpsharp:latest

Version tags such as v1.2.3 also publish image tags like v1.2.3, 1.2.3, and 1.2. Read-only mode is on by default; set GITLABMCP_Gitlab__ReadOnly=false only when you want write tools available.

Running as a Windows Service

The host detects when it's launched by the Service Control Manager and switches to service mode automatically (config and logs resolve from the executable directory, not the SCM's C:\Windows\System32 working directory).

Publish, then register with sc.exe (run as Administrator):

dotnet publish -c Release -r win-x64 --self-contained false -o C:\Services\GitlabMCPSharp

sc.exe create GitlabMCPSharp `
    binPath= "C:\Services\GitlabMCPSharp\GitlabMCPSharp.exe" `
    start= auto `
    DisplayName= "GitLab MCP (C#)"
sc.exe description GitlabMCPSharp "MCP server for GitLab."
sc.exe start GitlabMCPSharp

Put credentials in C:\Services\GitlabMCPSharp\GitlabMCPSharp.Local.json (or set GITLABMCP_Gitlab__PersonalAccessToken as a machine-level env var) — never in GitlabMCPSharp.json, which is checked in.

To remove:

sc.exe stop GitlabMCPSharp
sc.exe delete GitlabMCPSharp

Logs land in <install-dir>\logs\gitlabmcp-*.log.

Read-only mode

Read-only is on by default. To enable write tools (e.g. gl_create_issue, gl_trigger_pipeline), set Gitlab:ReadOnly=false.

Merge request review

Full MR review surface (gated by Gitlab:EnableMergeRequests):

• View: gl_list_merge_requests, gl_get_merge_request, gl_list_merge_request_changes (per-file diff), gl_get_merge_request_diff (concatenated unified diff), gl_get_merge_request_approval_state, gl_list_merge_request_discussions, gl_list_merge_request_notes, gl_list_merge_request_pipelines.
• Create: gl_create_merge_request (title, source → target branch, optional description, draft, removeSourceBranch).
• Decide: gl_approve_merge_request, gl_unapprove_merge_request (per-user, via the raw API endpoint).
• Discuss: gl_add_merge_request_note (conversation), gl_add_merge_request_discussion (new thread).
• Complete: gl_merge_merge_request (optional squash, removeSourceBranch, merge commit message).
• Cancel: gl_close_merge_request; gl_reopen_merge_request to undo.

All create/decide/discuss/complete/cancel tools require Gitlab:ReadOnly=false.

The create → review → comment → approve → complete lifecycle is unified across the GitHub, Azure DevOps and GitLab MCP servers (see each server's README).

Pipelines / CI

Pipeline tools (gated by Gitlab:EnablePipelines) let you diagnose a failing pipeline down to the individual job:

• Pipelines: gl_list_pipelines, gl_get_pipeline.
• Per-job: gl_list_pipeline_jobs lists each job with its stage, status, timing, allow_failure and failure_reason (pass onlyFailed=true to narrow to the jobs that broke); gl_get_job_log fetches a single job's trace (log), truncated to maxBytes (default 200 KB) to protect agent context.
• Trigger: gl_trigger_pipeline (requires Gitlab:ReadOnly=false).

Typical flow: gl_list_pipelines → gl_list_pipeline_jobs pipelineId onlyFailed=true → gl_get_job_log jobId. This mirrors the per-job log flow in the Azure DevOps and GitHub MCP servers.