Windows Github Auth Diagnosis

Windows GitHub Auth Diagnosis

Use this skill before declaring GitHub authentication broken on Windows when the failing command ran inside a Codex, agent, or tool sandbox.

Core Rule

Treat sandbox-only GitHub authentication failures as false-negative candidates until a keyring-capable path proves otherwise. Some Windows agent sandboxes cannot read Credential Manager or another configured keyring even when GitHub CLI and Git are correctly authenticated in a normal terminal.

Do not run or suggest gh auth login, gh auth logout, or gh auth refresh based only on a sandbox HTTP 401, Bad credentials, invalid default token, or SEC_E_NO_CREDENTIALS result.

Known False-Negative Symptoms

• gh auth status -h github.com --json hosts returns HTTP 401, Bad credentials, or an invalid default token from a sandboxed command.
• gh api user --jq .login returns Requires authentication (HTTP 401) from a sandboxed command.
• git ls-remote, git fetch, git pull, or git push over HTTPS fails with schannel: AcquireCredentialsHandle failed: SEC_E_NO_CREDENTIALS from a sandboxed command.

Procedure

1. Confirm repository remote wiring:

   git -C <repo> remote -v
   

   If origin is missing, classify the problem as NO_ORIGIN or remote misconfiguration, not as GitHub authentication failure.

2. Check credential helper configuration:

   git -C <repo> config --get-all credential.helper
   git -C <repo> config --get-all credential.https://github.com.helper
   

3. Run the proof commands from a keyring-capable execution path without printing token values. In Codex, if sandboxed commands fail with the symptoms above, use the smallest available unsandboxed or approval-backed command path for only these proof commands:

   gh auth status -h github.com --json hosts
   gh api user --jq .login
   GIT_TERMINAL_PROMPT=0 git -C <repo> ls-remote origin HEAD
   

   If a proof command fails in a way that can be transient, such as a network timeout, a DNS or proxy hiccup, or temporary GitHub unavailability, retry the same command once before classifying the result. Classify only reproducible failures.

4. Treat GitHub authentication as healthy only when all of these are true:

   • gh auth status reports state=success.
   • gh auth status reports tokenSource=keyring, the documented keyring-backed source for the environment, or an environment-variable token source such as GH_TOKEN or GITHUB_TOKEN. An environment-variable token does not depend on keyring visibility, so when the remaining proof checks pass it is a valid healthy state, not a false-negative candidate.
   • gh api user --jq .login returns the expected login.
   • GIT_TERMINAL_PROMPT=0 git -C <repo> ls-remote origin HEAD returns a ref, unless the remote is intentionally empty and stderr plus exit status show authentication succeeded.

5. If keyring proof succeeds, classify the sandbox 401, Bad credentials, invalid default token, or SEC_E_NO_CREDENTIALS result as a sandbox false negative. Continue push, PR, review, merge, or other GitHub work through the same keyring-capable execution path.

Exceptions To Preserve

• NO_ORIGIN: missing or wrong origin is a remote configuration problem.
• Empty repository: ls-remote origin HEAD can return no ref for a truly empty remote; inspect stderr and exit status before calling it auth failure.
• Branch protection: push rejection from protected branches is not authentication failure.
• Permission or scope shortage: successful login with a failed operation can still indicate missing repository permission or token scope.
• Network outage: DNS, TLS, proxy, or GitHub availability problems are separate from credential health.
• Agent approval layer rejection: if a tool approval layer blocks git push or a GitHub command, classify it as an approval or permission-layer blocker, not GitHub auth failure.

Prohibited Responses

• Do not print token values or run commands such as gh auth token or gh auth status --show-token.
• Do not ask for OAuth, token, secret, or credential entry based only on sandboxed failures.
• Do not run or suggest gh auth login, gh auth logout, or gh auth refresh until the keyring-capable proof path also fails and no exception explains the result.
• Do not wait in OAuth or token-entry loops.
• Do not paste real secrets, real authentication logs, cookies, screenshots, or customer data into public issues or chat reports.

Reporting Template

When reporting the diagnosis, include only safe facts:

• sandbox symptom and command class, without tokens or secret-bearing logs
• remote wiring result
• credential helper result, with no secret values
• keyring-capable proof result: success or failure
• final classification: false negative, remote misconfiguration, permission/scope issue, branch protection, network issue, approval-layer blocker, or unresolved
• next command to continue, if safe

Note: the repository's private-marker scanner (scripts/scan-private-markers.ps1) is a best-effort guard against leaking secrets into public artifacts. It does not recognize every secret format, so always sanitize reports and issues by hand rather than relying on the scan alone.