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## Summary Same shape of bug as #1215's cursor fix, different filter. The RemoteURL filter built its WHERE predicate using `jsonb_array_elements` + `->>` extraction, which the planner can't translate into a GIN search. Replaced with a JSONB containment predicate `@>` that uses `idx_servers_json_remotes`. ## Diagnosis (from the per-phase publish slog #1215 added) Today's first publish-latency alert at 17:08 UTC pointed straight at this: ``` publish complete server_name=dev.storage/mcp version=1.10.1 total_ms=14822 validate_ms=0 lock_ms=238 remotes_ms=10980 version_checks_ms=535 unmark_ms=3014 create_ms=53 ``` `remotes_ms=10,980` on a server with **one** remote URL pointed at `validateNoDuplicateRemoteURLs`, which runs the RemoteURL filter against the database. EXPLAIN ANALYZE on prod confirmed: ``` Filter: (status != 'deleted') AND EXISTS(SubPlan 1) Rows Removed by Filter: 21,092 ← scans the whole table Buffers: shared hit=20,028 Execution Time: 10,005 ms ``` ## Fix `internal/database/postgres.go:99` rewritten: ```sql -- before (planner can't use GIN index for this) EXISTS (SELECT 1 FROM jsonb_array_elements(value->'remotes') AS remote WHERE remote->>'url' = $1) -- after (GIN-indexable) value -> 'remotes' @> jsonb_build_array(jsonb_build_object('url', $1::text)) ``` Semantically equivalent for our schema (`url` is always a string, NOT NULL). ## Local benchmark — 20K rows, prod-shaped JSONB (~1KB/row) | Form | Buffer hits | Index used | Time | |------|------------:|------------|-----:| | OLD | 40,398 | none — full scan | 17.0 ms | | NEW | **294** | **`idx_servers_json_remotes` GIN bitmap** | **1.6 ms** | Maps to prod's 10,005 ms cold-cache observation — same shape of speedup we got from the cursor fix. ## Scope honesty This PR addresses the **publish slowness path** (`validateNoDuplicateRemoteURLs` in the publish transaction). It directly resolves today's 17:08 UTC `Publish Endpoint Latency` alert. It does **not** address: - Today's 17:35–17:40 UTC `Availability dropped below 95%` alert. Per-investigation: only 4 publishes happened in the entire 17:00–17:50 window and zero during the burst minutes — so my initial "concurrent slow publishes starved the pool" hypothesis was wrong. The actual cause was scraper-driven concurrency (4,500+ requests in 5 min) on plain cursor pagination + ILIKE substring search, where individual queries are fast (mean 42 ms) but tail latency under concurrency reaches 10 s server-side and 20–35 s nginx-level due to pool queueing. - The 18:17 UTC `Publish Endpoint Latency` re-fire (same scraper-driven concurrency). A follow-up PR will raise pool size + PG `max_connections` + add explicit PG resource limits to absorb concurrency without queue blowup. That fix has a different shape (config) and a different risk profile (PG restart for `max_connections`); kept separate so this surgical SQL change can ship cleanly. ## Test plan - [x] `go build ./...` clean - [x] `make lint` clean - [x] `go test -race ./internal/database/... ./internal/service/...` green — existing `TestPostgreSQL_ListServers/filter by remote URL` covers semantic correctness - [x] EXPLAIN ANALYZE comparison locally on 20K rows + prod-shaped JSONB - [ ] After merge + deploy: verify on prod via `EXPLAIN ANALYZE`; confirm `remotes_ms` in `publish complete` slog drops to single-digit ms ## Out of scope (separate follow-ups) - pgxpool `MaxConns` / `MinConns` bump + PG `max_connections` raise + PG `resources` limits — addresses the cursor-tail and ILIKE-search concurrency that this PR doesn't touch - Per-IP rate limiting at nginx — defends against scraper retry storms regardless of query speed - `Cache-Control` headers on `/v0/servers` — let nginx absorb scraper repeats - Pre-existing `superfluous WriteHeader` warnings — separate Huma framework issue - ILIKE substring search on `server_name` is unindexable — could be replaced with `pg_trgm` GIN index or full-text search 🤖 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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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!