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| Filename | Latest commit message | Latest commit date |
|---|---|---|
## Summary
- Remap recorded status to `499` (NGINX-style "client closed") when
`ctx.Context().Err()` is `context.Canceled` after the handler returns
- Skip the `http_errors_total` increment for `499`s so the availability
metric reflects server-visible errors only
## Why
Under scraper-driven load, clients with short timeouts paginate
`/v0.1/servers`, give up while PG is busy, and close the TCP connection.
The handler's DB iteration returns `context canceled`, the handler
converts that to `huma.Error500InternalServerError`, and tries to write
a response to the now-closed socket. NGINX records `499` (client closed)
and never delivers anything to the client — but the registry's
middleware records `status_code=500` and bumps
`mcp_registry_http_errors_total`.
That's what's been firing the `Availability dropped below 95%` alert
during the daily 17:00 UTC bursts. Recent prod numbers from one pod
(~19h uptime):
```
mcp_registry_http_errors_total{path="/v0.1/servers", status_code="500"} 7396
mcp_registry_http_errors_total{path="/v0.1/servers/{serverName}/versions", status_code="500"} 283
mcp_registry_http_errors_total{path="/v0/servers", status_code="500"} 352
```
…against zero 5xx in NGINX ingress logs over the same window. The alert
was correct *given the data it had*; the data was misclassifying client
cancellations as server errors.
## What this does
In `internal/api/router/router.go` (the metric middleware): after
`next(ctx)`, check `ctx.Context().Err()`. If it's `context.Canceled`,
override `statusCode` to `499` and skip the error counter. Requests
counter and duration histogram still record so the cancellation rate
stays visible.
`context.DeadlineExceeded` is intentionally **not** remapped — that
would indicate a server-side timeout if we ever add per-request
deadlines, and should still count as a server error.
## What this does *not* do
- Doesn't reduce the underlying load (ServiceNow + notion catalog
scrapers driving the daily peak — separate work, see the `updated_since`
outreach we're doing).
- Doesn't change handler behaviour — handlers still call
`huma.Error500…` on `context.Canceled`. We could short-circuit earlier
(return without writing) to save the work, but that's a bigger refactor
and the metric fix unblocks the alert immediately.
## Companion change (no code, just a Grafana annotation tweak)
The `Availability dropped below 95%` alert (UID `bexrc60etvhmoa`)
currently has the annotation:
> No. of 5xx are increased from acceptable limit i.e. 5% of total
throughput
The query is on `mcp_registry_http_errors_total`, not 5xx specifically.
After this change the count is meaningful again, but the wording is
still misleading. Suggest updating to:
> Internal error rate exceeded 5% of total throughput
(no PromQL change required.)
## Test plan
- [x] `go test ./internal/api/router/...` — new test passes
- [x] `golangci-lint run ./internal/...` — clean
- [ ] After merge, watch a daily 17:00 UTC burst —
`mcp_registry_http_errors_total{status_code="500",
path="/v0.1/servers"}` should stay flat while
`mcp_registry_http_requests_total{status_code="499",
path="/v0.1/servers"}` grows. Availability alert should not fire on
cancellation-only bursts.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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| internal | ||
| pkg | ||
| scripts | ||
| tests/integration | ||
| tools | ||
| .env.example | ||
| .gitignore | ||
| .golangci.yml | ||
| .goreleaser.yaml | ||
| .ko.dockerignore | ||
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| CHANGES.md | ||
| CLAUDE.md | ||
| complete.md | ||
| CONTRIBUTING.md | ||
| docker-compose.yml | ||
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| LICENSE | ||
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| SECURITY.md | ||
MCP Registry
The MCP registry provides MCP clients with a list of MCP servers, like an app store for MCP servers.
📤 Publish my MCP server | ⚡️ Live API docs | 👀 Ecosystem vision | 📖 Full documentation
Development Status
2025-10-24 update: The Registry API has entered an API freeze (v0.1) 🎉. For the next month or more, the API will remain stable with no breaking changes, allowing integrators to confidently implement support. This freeze applies to v0.1 while development continues on v0. We'll use this period to validate the API in real-world integrations and gather feedback to shape v1 for general availability. Thank you to everyone for your contributions and patience—your involvement has been key to getting us here!
2025-09-08 update: The registry has launched in preview 🎉 (announcement blog post). While the system is now more stable, this is still a preview release and breaking changes or data resets may occur. A general availability (GA) release will follow later. We'd love your feedback in GitHub discussions or in the #registry-dev Discord (joining details here).
Current key maintainers:
- Adam Jones (Anthropic) @domdomegg
- Tadas Antanavicius (PulseMCP) @tadasant
- Toby Padilla (GitHub) @toby
- Radoslav (Rado) Dimitrov (Stacklok) @rdimitrov
Contributing
We use multiple channels for collaboration - see modelcontextprotocol.io/community/communication.
Often (but not always) ideas flow through this pipeline:
- Discord - Real-time community discussions
- Discussions - Propose and discuss product/technical requirements
- Issues - Track well-scoped technical work
- Pull Requests - Contribute work towards issues
Quick start:
Pre-requisites
- Docker
- Go 1.24.x
- ko - Container image builder for Go (installation instructions)
- golangci-lint v2.4.0
Running the server
# Start full development environment
make dev-compose
This starts the registry at localhost:8080 with PostgreSQL. The database uses ephemeral storage and is reset each time you restart the containers, ensuring a clean state for development and testing.
Note: The registry uses ko to build container images. The make dev-compose command automatically builds the registry image with ko and loads it into your local Docker daemon before starting the services.
By default, the registry seeds from the production API with a filtered subset of servers (to keep startup fast). This ensures your local environment mirrors production behavior and all seed data passes validation. For offline development you can seed from a file without validation with MCP_REGISTRY_SEED_FROM=data/seed.json MCP_REGISTRY_ENABLE_REGISTRY_VALIDATION=false make dev-compose.
The setup can be configured with environment variables in docker-compose.yml - see .env.example for a reference.
Alternative: Running a pre-built Docker image
Pre-built Docker images are automatically published to GitHub Container Registry. Note that the image does not bundle PostgreSQL, so you need to run your own and point the registry at it via MCP_REGISTRY_DATABASE_URL (see docker-compose.yml for a working example):
# Run latest stable release
docker run -p 8080:8080 ghcr.io/modelcontextprotocol/registry:latest
# Run latest from main branch (continuous deployment)
docker run -p 8080:8080 ghcr.io/modelcontextprotocol/registry:main
# Run specific release version
docker run -p 8080:8080 ghcr.io/modelcontextprotocol/registry:v1.0.0
# Run development build from main branch
docker run -p 8080:8080 ghcr.io/modelcontextprotocol/registry:main-20250906-abc123d
Available tags:
- Releases:
latest,v1.0.0,v1.1.0, etc. - Continuous:
main(latest main branch build) - Development:
main-<date>-<sha>(specific commit builds)
Publishing a server
To publish a server, we've built a simple CLI. You can use it with:
# Build the latest CLI
make publisher
# Use it!
./bin/mcp-publisher --help
See the publisher guide for more details.
Other commands
# Run lint, unit tests and integration tests
make check
There are also a few more helpful commands for development. Run make help to learn more, or look in Makefile.
Architecture
Project Structure
├── cmd/ # Application entry points
│ └── publisher/ # Server publishing tool
├── data/ # Seed data
├── deploy/ # Deployment configuration (Pulumi)
├── docs/ # Documentation
├── internal/ # Private application code
│ ├── api/ # HTTP handlers and routing
│ ├── auth/ # Authentication (GitHub OAuth, JWT, namespace blocking)
│ ├── config/ # Configuration management
│ ├── database/ # Data persistence (PostgreSQL)
│ ├── service/ # Business logic
│ ├── telemetry/ # Metrics and monitoring
│ └── validators/ # Input validation
├── pkg/ # Public packages
│ ├── api/ # API types and structures
│ │ └── v0/ # Version 0 API types
│ └── model/ # Data models for server.json
├── scripts/ # Development and testing scripts
├── tests/ # Integration tests
└── tools/ # CLI tools and utilities
└── validate-*.sh # Schema validation tools
Authentication
Publishing supports multiple authentication methods:
- GitHub OAuth - For publishing by logging into GitHub
- GitHub OIDC - For publishing from GitHub Actions
- DNS verification - For proving ownership of a domain and its subdomains
- HTTP verification - For proving ownership of a domain
The registry validates namespace ownership when publishing. E.g. to publish...:
io.github.domdomegg/my-cool-mcpyou must login to GitHub asdomdomegg, or be in a GitHub Action on domdomegg's reposme.adamjones/my-cool-mcpyou must prove ownership ofadamjones.mevia DNS or HTTP challenge
Community Projects
Check out community projects to explore notable registry-related work created by the community.
More documentation
See the documentation for more details if your question has not been answered here!