Claude Code Action exits with 404

**Describe the bug**

See action here: https://github.com/kratsg/giordonstark.com/actions/runs/31735352514/job/94565523232 triggered via an `@claude`.

Initial log at top-level

  Running Claude with prompt from file: /home/runner/work/_temp/claude-prompts/claude-prompt.txt

  SDK options: {

    "allowedTools": [

      "Glob",

      "Grep",

      "LS",

      "Read",

      "mcp__github_comment__update_claude_comment",

      "mcp__github_ci__get_ci_status",

      "mcp__github_ci__get_workflow_run_details",

      "mcp__github_ci__download_job_log",

      "Bash(git add:*)",

      "Bash(git commit:*)",

      "Bash(/home/runner/work/_actions/anthropics/claude-code-action/239e3a730883eeb5c53db12b0fc9573b3024b126/scripts/git-push.sh:*)",

      "Bash(git rm:*)"

    ],

    "systemPrompt": {

      "type": "preset",

      "preset": "claude_code"

    },

    "pathToClaudeCodeExecutable": "/home/runner/.local/bin/claude",

    "settingSources": [

      "user",

      "project",

      "local"

    ]

  }

  {

    "type": "system",

    "subtype": "init",

    "message": "Claude Code initialized",

    "model": "claude-sonnet-5"

  }

  {

    "type": "result",

    "subtype": "success",

    "is_error": true,

    "duration_ms": 1900,

    "num_turns": 1,

    "total_cost_usd": 0,

    "permission_denials_count": 0

  }

  Log saved to /home/runner/work/_temp/claude-execution-output.json

  Set session_id: 831a665a-f0ec-4d06-9ac0-decf7a02276a

  Error: Claude result reported subtype success with is_error:true (run did not complete successfully)

  Error: Action failed with error: Claude execution failed: result is_error:true

But what's confusing is that it's trying to do a comparison of a branch it has not yet created. Not clear to me why it would do this. Is this a prompting issue or something else?

Unable to get branch...

  Fetching issue comment 5285342908

  Successfully fetched as issue comment

  GET /repos/kratsg/giordonstark.com/branches/claude%2Fissue-44-20260813-1920 - 404 with id E441:184EB3:262364F:821D3E0:6A7E1921 in 189ms

  Branch claude/issue-44-20260813-1920 does not exist remotely

  Branch claude/issue-44-20260813-1920 does not exist remotely, no branch link will be added

  GET /repos/kratsg/giordonstark.com/compare/main...claude%2Fissue-44-20260813-1920 - 404 with id E441:184EB3:2623770:821D7CE:6A7E1922 in 193ms

  Error checking for changes in branch: 117 |       request: requestOptions

  118 |     });

  119 |   }

  120 |   if (status >= 400) {

  121 |     octokitResponse.data = await getResponseData(fetchResponse);

  122 |     throw new RequestError(toErrorMessage(octokitResponse.data), status, {

                  ^

  HttpError: Not Found - https://docs.github.com/rest/commits/commits#compare-two-commits

     status: 404,

    request: {

    method: "GET",

    url: "https://api.github.com/repos/kratsg/giordonstark.com/compare/main...claude%2Fissue-44-20260813-1920",

    headers: [Object ...],

    request: [Object ...],

  },

   response: {

    url: "https://api.github.com/repos/kratsg/giordonstark.com/compare/main...claude%2Fissue-44-20260813-1920",

    status: 404,

    headers: [Object ...],

    data: [Object ...],

  },

        at fetchWrapper (/home/runner/work/_actions/anthropics/claude-code-action/239e3a730883eeb5c53db12b0fc9573b3024b126/node_modules/@octokit/rest/node_modules/@octokit/core/node_modules/@octokit/request/dist-bundle/index.js:122:11)

  ✅ Updated issue comment 5285342908 with job link

**Expected behavior**

Claude creates a branch and pushes the branch to the repository with the code changes requested by me.

**Workflow yml file**

https://github.com/kratsg/giordonstark.com/blob/95de29e/.github/workflows/claude.yml

**API Provider**

[x] Anthropic First-Party API (default)
[ ] AWS Bedrock
[ ] GCP Vertex

**Additional context**

none