GitHub Actions / GitHub Actions

GitHub Actions SSH Deployment Permission Denied (publickey) — ED25519 vs RSA Key Format Mismatch

Developer's GitHub Actions workflow fails with SSH permission denied during git clone or deploy step. Root cause often involves mismatched key formats (ED25519 public key vs RSA private key in secrets), truncated PEM in secret values, or ssh-agent not initialized in runner environment. Includes evidence for GitHub Actions troubleshooting demand.

Source-backed Last updated June 2, 2026 4 sources Needs local verification

Category: GitHub Actions
Error signature: git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format
Quick fix: Check the build output, project root, and deployment platform configuration before redeploying.
Updated: June 2, 2026
Verification status: Source-backed
Evidence: 4 public source URLs

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for GitHub Actions, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format is a GitHub Actions failure pattern reported for developers trying to developer's github actions workflow fails with ssh permission denied during git clone or deploy step. root cause often involves mismatched key formats (ed25519 public key vs rsa private key in secrets), truncated pem in secret values, or ssh-agent not initialized in runner environment.. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Stack Overflow and GitHub Discussions extensively cover this pattern. Common variants: ed25519 public key but RSA private key pasted into GitHub secrets (multiple SO answers), PEM key truncated missing '-----END RSA PRIVATE KEY-----' line (SO answer), ssh-agent not initialized on ubuntu-latest runner. WP Engine deploy action (#50) and Maven release plugin (#51) both have open issues. Category mapping: GitHub Actions CI/CD auth error → 'GitHub Actions'. Not in dev-error-db.

Common causes

Stack Overflow and GitHub Discussions extensively cover this pattern. Common variants: ed25519 public key but RSA private key pasted into GitHub secrets (multiple SO answers), PEM key truncated missing '-----END RSA PRIVATE KEY-----' line (SO answer), ssh-agent not initialized on ubuntu-latest runner. WP Engine deploy action (#50) and Maven release plugin (#51) both have open issues. Category mapping: GitHub Actions CI/CD auth error → 'GitHub Actions'. Not in dev-error-db.

Quick fixes

Confirm the exact error signature matches git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format.
Check the GitHub Actions account, local tool state, and provider configuration involved in the failing workflow.
Check the build output, project root, and deployment platform configuration before redeploying.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format exactly before applying the quick fix.
Compare the failing environment with GitHub Actions versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format mean in GitHub Actions?

git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format indicates the workflow described by "GitHub Actions SSH Deployment Permission Denied (publickey) — ED25519 vs RSA Key Format Mismatch" failed in a GitHub Actions context. Start by confirming the exact signature and the component that emitted it.

What should I check first for git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format?

Check whether this cause matches your environment: Stack Overflow and GitHub Discussions extensively cover this pattern. Common variants: ed25519 public key but RSA private key pasted into GitHub secrets (multiple SO answers), PEM key truncated missing '-----END RSA PRIVATE KEY-----' line (SO answer), ssh-agent not initialized on ubuntu-latest runner. WP Engine deploy action (#50) and Maven release plugin (#51) both have open issues. Category mapping: GitHub Actions CI/CD auth error → 'GitHub Actions'. Not in dev-error-db.

Is the git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format guidance source-backed?

The "GitHub Actions SSH Deployment Permission Denied (publickey) — ED25519 vs RSA Key Format Mismatch" page is labeled source-backed. It has 4 public source URLs from stackoverflow.com, github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format?

For "GitHub Actions SSH Deployment Permission Denied (publickey) — ED25519 vs RSA Key Format Mismatch", avoid applying "Check the build output, project root, and deployment platform configuration before redeploying." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging git@github.com: Permission denied (publickey). Load key '/github/home/.ssh/id_ed25519': invalid format?

For "GitHub Actions SSH Deployment Permission Denied (publickey) — ED25519 vs RSA Key Format Mismatch", collect the failing GitHub Actions command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.