Mirror of https://github.com/modelcontextprotocol/registry — A community driven registry service for Model Context Protocol (MCP) servers.
  • Go 92.9%
  • PLpgSQL 3.1%
  • HTML 1.9%
  • Shell 1.6%
  • Makefile 0.5%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Radoslav Dimitrov c5f50e817b
fix(auth): better DNS verification errors and wrong-selector hint (#1202)
## Summary

DNS auth users have repeatedly hit two failure modes that both produce
the same opaque "Ed25519 signature verification failed" error, making
them indistinguishable to debug. This PR makes both diagnosable
end-to-end without changing the auth protocol or any successful path.

The two recurring failure modes:

1. **Wrong placement** — TXT record put under a selector
(`_mcp-auth.<domain>` or `_mcp-registry.<domain>`) instead of the apex.
DKIM-style intuition, but MCP DNS auth uses SPF-style apex placement.
See #385 (PR #388 fixed the docs but the failure recurred), #1103,
#1126.
2. **Stale apex record** — old TXT record left behind after a key
rotation, silently tried first and rejected.

## Changes

**`internal/api/handlers/v0/auth/dns.go`** — when the apex has no
`v=MCPv1` record, probe `_mcp-auth.<domain>` and
`_mcp-registry.<domain>` in parallel (2s individual timeout). If a
record is found there, return a targeted error pointing the user at the
apex. Costs zero extra DNS work in the success path.

**`internal/api/handlers/v0/auth/common.go`** — when verification fails
against records that *are* present, include short fingerprints of every
key the registry tried (`ed25519:YJLsHFhu`-style 8-char prefix). A new
`ErrSignatureMismatch` sentinel keeps structural errors (wrong signature
size, unsupported algorithm) passing through unchanged via `errors.Is`,
so existing assertions on those messages still hold.

**`docs/modelcontextprotocol-io/authentication.mdx`** — anti-pattern
`<Warning>` callout in the DNS section explicitly warning against
selector placement and stale records.

**Tests** — two new tests:
- `TestDNSAuthHandler_WrongSelectorProbe` — verifies the probe surfaces
records found at `_mcp-auth.` / `_mcp-registry.` and falls through to
the standard error when nothing is found anywhere
- `TestDNSAuthHandler_StaleKeyFingerprintInError` — verifies the
fingerprint hint appears in the failure message for #1126's exact
scenario

One existing test assertion was updated from a generic `"signature
verification failed"` substring to the more specific `"invalid signature
size for ECDSA P-384"` it should always have been asserting; the new
sentinel-based logic surfaces structural errors verbatim.

## Test plan

- [x] `make lint` — clean
- [x] `make test-unit` — all auth tests pass (existing + 2 new)
- [x] Verified existing single-key and multi-key paths preserve their
original (more specific) error messages where they were already specific
- [ ] Reviewer to sanity-check the docs callout renders well in the
Mintlify theme

## Out of scope

The publisher-side preflight DNS check (cross-link in #845) is
intentionally **not** in this PR — that belongs in the broader CLI UX
work tracked by #845.

Refs #845, #385, #1103
Fixes #1126

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-25 11:22:06 -04:00
.githooks Add linting documentation and pre-commit hooks (#177) 2025-07-15 09:31:17 -07:00
.github build(deps): bump goreleaser/goreleaser-action from 7.0.0 to 7.1.0 in the actions group (#1189) 2026-04-21 05:02:23 -04:00
.vscode Move publisher CLI from tools/ to cmd/ (#326) 2025-08-29 14:45:36 +01:00
cmd fix(publisher): honor mcpName as the authoritative server name in init (#1195) 2026-04-25 07:14:11 -07:00
data chore: Release server.json schema version 2025-12-11 (#841) 2025-12-12 09:33:57 -08:00
deploy build(deps): bump github.com/pulumi/pulumi/sdk/v3 from 3.231.0 to 3.232.0 in /deploy (#1194) 2026-04-24 04:54:09 -04:00
docs fix(auth): better DNS verification errors and wrong-selector hint (#1202) 2026-04-25 11:22:06 -04:00
internal fix(auth): better DNS verification errors and wrong-selector hint (#1202) 2026-04-25 11:22:06 -04:00
pkg feat(oci): add support for Quay.io registry (#1150) 2026-04-24 06:11:46 -04:00
scripts docs: update API endpoint documentation from /v0/ to /v0.1/ (#802) 2025-12-04 13:02:45 -08:00
tests/integration fix: store tokens in ~/.config/mcp-publisher/ instead of cwd (#1166) 2026-04-15 03:23:07 -04:00
tools feat(oci): add support for Quay.io registry (#1150) 2026-04-24 06:11:46 -04:00
.env.example fix: seed from production API by default to ensure validation passes (#611) 2025-10-03 23:58:37 +03:00
.gitignore Enhanced server.json validation (phase 1) (#636) 2026-01-16 00:49:39 +02:00
.golangci.yml Stop pinning Go to patch versions, use stable in CI (#1137) 2026-04-09 11:57:21 -04:00
.goreleaser.yaml Update Goreleaser and Cosign (#839) 2025-12-11 08:43:57 -08:00
.ko.dockerignore Use ko in favour of docker build (#708) 2025-10-29 15:16:11 +00:00
.ko.yaml Use ko in favour of docker build (#708) 2025-10-29 15:16:11 +00:00
CHANGES.md Added /validate endpoint and modified mcp-publish so that all validation happens there (#896) 2026-02-04 15:52:07 +02:00
CLAUDE.md Add contributing guidelines to prevent seed.json PRs (#1079) 2026-03-22 07:42:18 -07:00
complete.md fix: store tokens in ~/.config/mcp-publisher/ instead of cwd (#1166) 2026-04-15 03:23:07 -04:00
CONTRIBUTING.md Add contributing guidelines to prevent seed.json PRs (#1079) 2026-03-22 07:42:18 -07:00
docker-compose.yml Use ko in favour of docker build (#708) 2025-10-29 15:16:11 +00:00
go.mod build(deps): bump github.com/jackc/pgx/v5 from 5.9.1 to 5.9.2 (#1188) 2026-04-21 05:02:43 -04:00
go.sum build(deps): bump github.com/jackc/pgx/v5 from 5.9.1 to 5.9.2 (#1188) 2026-04-21 05:02:43 -04:00
LICENSE chore: update licensing to Apache 2.0 for new contributions (#887) 2026-01-13 11:11:20 +02:00
Makefile Ensure tests are failing CI (#840) 2025-12-11 09:56:57 +02:00
README.md docs: note PostgreSQL requirement for prebuilt Docker image (#1196) 2026-04-25 07:15:00 -07:00
SECURITY.md Update SECURITY.md to use GitHub Security Advisories (#977) 2026-02-18 23:36:23 -08:00

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:

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

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-mcp you must login to GitHub as domdomegg, or be in a GitHub Action on domdomegg's repos
  • me.adamjones/my-cool-mcp you must prove ownership of adamjones.me via 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!