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| Filename | Latest commit message | Latest commit date |
|---|---|---|
## The bug (scoped to `github-at`)
When you exchange a GitHub OAuth/PAT token for a registry JWT, the
handler granted `io.github.<org>/*` publish permission for **every**
organization you belong to. It derived that list from [`GET
/users/{username}/orgs`](https://docs.github.com/en/rest/orgs/orgs#list-organizations-for-a-user),
which:
1. returns only **public** org memberships, and
2. carries **no role** — an org Owner and a brand-new member look
identical.
So membership was silently treated as publishing authority. Anyone who
is (or whose public membership lists them as) a member of `acme` could
publish — and, because publish is a pure namespace-glob with no
per-server ownership check, **overwrite** — any server under
`io.github.acme/*`.
## The fix
Switch to [`GET
/user/memberships/orgs`](https://docs.github.com/en/rest/orgs/members#list-organization-memberships-for-the-authenticated-user),
which returns the **authenticated caller's role** per org (and includes
private memberships), and grant the org namespace only when the role is
`admin` (org Owner).
- **Personal namespaces are unchanged** — you always get
`io.github.<your-username>/*`.
- **Org namespaces now require Owner.** GitHub has no org-level
"maintainer" role; org membership is either `admin` (Owner) or `member`.
We grant only on `admin`.
- **`read:org` is the only scope needed.** A minimal token without it
still authenticates and still publishes to your personal namespace; a
genuine missing-scope `403` from the memberships call is treated as "no
admin orgs" rather than a hard failure, so we don't push anyone to
over-scope a token. A `403`/`429` that is actually a rate limit
(`X-RateLimit-Remaining: 0` / `Retry-After`) fails closed instead, so a
throttle can't silently strip a real Owner's org grant. Critically, the
token needs **no repository scopes** — the registry never reads or
writes code, so an org Owner can hand CI a near-powerless `read:org`
token.
The authorization decision stays stateless and delegated to GitHub — no
new storage, no new endpoints, no schema changes — consistent with
[design principle #2](docs/design/design-principles.md) (minimal
operational burden).
### Containing the CI token
The registry-side change makes the org Owner the only one who can mint
org-namespace authority. But if that Owner drops the resulting PAT into
a plain repo secret, **every repository writer** can reach it (via
branch/tag pushes that run repo-controlled build/test code in the
privileged job) — quietly re-widening publish access beyond Owners.
External fork contributors still cannot reach it by default (no secrets
on fork PRs, no branch push), barring misconfigurations like
`pull_request_target`-with-checkout or self-hosted runners on public
repos.
`docs/modelcontextprotocol-io/github-actions.mdx` documents how to
contain that blast radius:
- store the token as a **GitHub Actions Environment secret** (the PAT
example uses `environment:`),
- restrict that environment to the default branch / release tags and
require PR reviews on it, so only reviewed, maintainer-approved code can
reach the token,
- optionally add a **required environment reviewer** for explicit
per-publish approval,
- and avoid the two footguns (`pull_request_target` checkout,
self-hosted runners on public repos).
This shrinks *who holds* the org credential; it does not change the fact
that an authorized publish can still overwrite a different server in the
same namespace until per-server publisher ownership exists (the
follow-up noted below).
## Why this shape, given the alternatives
[Pree's
writeup](https://github.com/modelcontextprotocol/registry/issues/982#issuecomment-3982959559)
([Notion analysis
doc](https://www.notion.so/MCP-Registry-Authorization-Model-Analysis-Issue-982-31736f79f74980bc90c6e53de1c564c5))
is the clearest framing of the problem and the option space, laying out
three broad solutions:
- **Approach A — GitHub App as the authority layer.** Strong model, but
its natural unit of authority is a *repo*, so it needs a repo→server
mapping to authorize a namespace. The safe, flexible version of that
mapping is registry-managed state — which collapses into Approach B.
It's also GitHub-only.
- **Approach B — a registry-managed grants table** (OIDC bootstrap, or
device-flow admin check). The most capable and provider-agnostic option,
and probably where v1 wants to go. But it introduces exactly the
"registry manages an authorization database" layer we wanted to avoid
taking on right now: revocation, sync, audit, migration.
- **Approach C — scoped bearer tokens (npm-style).** Good ergonomics,
but again implies issuance/storage the registry would own.
The two-property test (does the registry control the decision? is it
granted through an act requiring real authority?) is the right lens.
This change satisfies it **without** new state: the registry makes the
decision (it filters on role), and the authority is real (live GitHub
Owner role, re-checked on every short-lived token exchange).
**What this deliberately gives up**, so reviewers can weigh it honestly:
- **Owners are always in the loop.** Only org Owners can publish org
servers; there's no delegated "this team can publish this server" — that
needs Approach B's state. Reduced flexibility in exchange for zero new
infrastructure.
- **Blast radius within an org is unchanged.** An Owner (or Owner-scoped
CI token) can still overwrite *any* server under the org namespace,
because there's still no per-server publisher ownership. That
hijack-an-existing-server problem is real but **orthogonal** to this fix
and belongs in its own change (record publisher identity per server;
enforce it on update) — a follow-up to take alongside the OIDC hardening
below.
- **OIDC is untouched and remains coarser.** The `github-oidc` path
still grants the whole `io.github.<owner>/*` namespace to any workflow
with `id-token: write`, i.e. effectively anyone with write access to any
repo in the org, and it excludes non-Actions CI (Jenkins/GitLab can't
mint GitHub Actions OIDC). The admin-PAT path here is the
higher-assurance option for org publishing; OIDC stays as a
lower-assurance Actions convenience to be tightened separately.
## Revocation
The registry JWT is **5-minute, no-refresh** (per #264/#273), so loss of
Owner status propagates within minutes on the next token exchange, with
no revocation list to maintain.
## Tests
`go test ./internal/api/handlers/v0/auth/...` passes, including:
- member-role org is **not** granted; only admin orgs are
- a missing-scope `403` (no `read:org`) still yields the personal
namespace and no error
- an admin org on a **later page** of memberships is still granted
(pagination correctness)
- a `5xx` from the memberships call **fails closed** (no token issued)
rather than degrading to personal-only
- a rate-limit `403` (`X-RateLimit-Remaining: 0` / `Retry-After`)
**fails closed** — not mistaken for a missing-scope `403`
- existing org/name-validation tests updated to the new endpoint + role
shape
`gofmt`/`go vet`/`golangci-lint` (CI-pinned v2.11.4) clean; CI green on
all checks.
## Live verification
Confirmed end-to-end against real `api.github.com` (not just mocks) by
exercising this branch's `ExchangeToken` and decoding the `permissions`
claim of the returned JWT.
A dedicated org, **Tadasant Test Org** (login `Tadasant-Test-Org`), is
Owned by one account and has a second account joined as a plain
**member**. Both memberships are `active`, verified via the same
endpoint the fix uses (`GET /user/memberships/orgs/{org}`):
| Token (role) | `io.github.Tadasant-Test-Org/*` granted? | Other
patterns granted |
|---|---|---|
| Owner (`admin`) | ✅ yes | personal `io.github.<owner>/*` |
| member | ❌ no | personal `io.github.<member>/*` + the orgs that
account actually Owns |
The member case is the meaningful one: that membership is **active and
returned** by `GET /user/memberships/orgs`, and is excluded purely
because its role is `member`, not `admin`. Under the previous `GET
/users/{username}/orgs` behavior (membership = authority, no role), the
same active membership **would have granted** the org namespace. The
role filter is also selective rather than blanket-deny — the member
account still receives the namespaces of the orgs where it genuinely
holds Owner.
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: Radoslav Dimitrov <radoslav@stacklok.com>
|
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| .githooks | ||
| .github | ||
| .vscode | ||
| cmd | ||
| data | ||
| deploy | ||
| docs | ||
| internal | ||
| pkg | ||
| scripts | ||
| tests/integration | ||
| tools | ||
| .env.example | ||
| .gitignore | ||
| .golangci.yml | ||
| .goreleaser.yaml | ||
| .ko.dockerignore | ||
| .ko.yaml | ||
| CHANGES.md | ||
| CLAUDE.md | ||
| complete.md | ||
| CONTRIBUTING.md | ||
| docker-compose.yml | ||
| go.mod | ||
| go.sum | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| 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).
Registry Working Group:
- Tadas Antanavicius (PulseMCP) @tadasant
- Radoslav (Rado) Dimitrov (Stacklok) @rdimitrov
- Bob Dickinson (TeamSpark) @BobDickinson
- Preeti (Pree) Dewani (Ravenmail) @pree-dew
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!