Unable to download the docker image

[akordowski]

I setup the MCP server as described in the README. But starting the server I get following errors:

[info] Starting server github
[info] Connection state: Starting
[info] Starting server from LocalProcess extension host
[info] Connection state: Starting
[info] Connection state: Running
[warning] [server stderr] Unable to find image 'ghcr.io/github/github-mcp-server:latest' locally
[warning] [server stderr] docker: Error response from daemon: Head "https://ghcr.io/v2/github/github-mcp-server/manifests/latest": denied: denied
[warning] [server stderr] 
[warning] [server stderr] Run 'docker run --help' for more information
[info] Connection state: Error Process exited with code 125

Any idea what I am doing wrong?

[edgeq]

➕ - also unable to pull the docker image. Even when pulling manually:

docker pull ghcr.io/github/github-mcp-server
Using default tag: latest
Error response from daemon: Head "https://ghcr.io/v2/github/github-mcp-server/manifests/latest": denied: denied

[edgeq]

My current workaround is to use the official anthropic mcp server. It's in deprecation, but it's a trusted source and still works.

[juruen]

@akordowski @edgeq is there any chance that you were logged into the gh docker registry with an expired token?

I'm unable to reproduce this as I can successfully pull the image anonymously:

juruen@moonbase:~$ docker logout ghcr.io  # logout from gh docker registry
Removing login credentials for ghcr.io
juruen@moonbase:~$ docker pull ghcr.io/github/github-mcp-server
Using default tag: latest
latest: Pulling from github/github-mcp-server
3d78e577de35: Pull complete
bfb59b82a9b6: Pull complete
4eff9a62d888: Pull complete
a62778643d56: Pull complete
7c12895b777b: Pull complete
3214acf345c0: Pull complete
5664b15f108b: Pull complete
0bab15eea81d: Pull complete
4aa0ea1413d3: Pull complete
da7816fa955e: Pull complete
9aee425378d2: Pull complete
d00c3209d929: Pull complete
221438ca359c: Pull complete
e76e88e5b481: Pull complete
4d3ee8eeb83f: Pull complete
Digest: sha256:faa1dfed068fb1d9c866a5ce4909947a5f2a5a72130815fba56c32bb441ca83f
Status: Downloaded newer image for ghcr.io/github/github-mcp-server:latest
ghcr.io/github/github-mcp-server:latest

[akordowski]

@juruen No, for the test I used a fresh created token. Are there maybe special rights that must be set for the token to access the registry?

[juruen]

@juruen No, for the test I used a fresh created token. Are there maybe special rights that must be set for the token to access the registry?

You should be able to pull the docker image anonymously, in the example I posted above, I do docker logout ghcr.io to make sure that I'm not logged in.

Any chance you could try that?

[akordowski]

You should be able to pull the docker image anonymously, in the example I posted above, I do docker logout ghcr.io to make sure that I'm not logged in.

The docker logout ghcr.io command helped and I was able to pull the image. I wonder why this was an issue, as I was not logged in into ghcr.io at all. At least at works. Thank you very much!

A note in the README regarding this issue might be helpful for other users.

[villyg]

Grooming summary and acceptance criteria for future occurrences of this issue (GHCR auth denied when pulling ghcr.io/github/github-mcp-server:latest):

Problem statement

• Starting the server via LocalProcess tries to pull ghcr.io/github/github-mcp-server:latest
• Docker responds with denied on manifest HEAD, causing exit code 125
• This is typically due to missing auth to GHCR or missing package permissions on the token

Likely root causes

• Docker not logged in to ghcr.io
• PAT missing read:packages scope
• Organization package visibility or SSO not authorized for the token
• Corporate proxy/cache interfering with GHCR requests

Acceptance criteria

1. Documentation updates

   • README and installation guides clearly instruct users to:
     • Log in to GHCR: echo $GH_PAT | docker login ghcr.io -u USERNAME --password-stdin
     • Ensure PAT scopes include read:packages at minimum (plus repo if needed)
     • If org-enforced SSO: verify the PAT is authorized for the organization
   • Add troubleshooting section for GHCR pull failures (denied/403/401), including proxy notes

2. Pre-flight checks (local server)

   • When using LocalProcess with Docker, detect unauthenticated GHCR access before pulling
   • Emit a clear actionable error message:
     • "Docker login to ghcr.io required. Ensure PAT with read:packages and run: docker login ghcr.io"
     • If token is present but scopes insufficient, advise adding read:packages

3. Fallback/alternate setup

   • Provide instructions (and a verified path) to run the server without Docker (direct binary or remote server option)
   • Confirm the remote server path works without GHCR and document headers required

4. Tests/verification

   • Add an integration test or script that simulates GHCR denied and asserts the server surfaces a friendly, actionable message
   • Smoke test: with valid GHCR login and PAT, docker run ghcr.io/github/github-mcp-server:latest --version succeeds

5. Success criteria

   • Users encountering GHCR denied can resolve the issue in < 5 minutes by following docs/error messages
   • Support receives significantly fewer tickets about GHCR 401/403/denied within one release cycle after docs and preflight improvements

Next actions

• [Docs] Update README/install guides with GHCR login and scopes (link to package permissions docs)
• [Server UX] Add preflight auth check + improved error for Docker pull path
• [QA] Add GHCR denied scenario test and pass

If maintainers prefer, we can open a follow-up issue to track the preflight check and doc changes explicitly.