Bedrock auth broken since v1.0.74 — "Could not load credentials from any providers" despite valid OIDC credentials

[aggie2020]

Hey there -- our Bedrock-based PR review workflow stopped working yesterday, which lines up with the v1.0.74/v1.0.75 releases. Hoping someone can point us in the right direction.

What's happening

Claude Code fails immediately with API Error: Could not load credentials from any providers, despite our OIDC credentials being set up and confirmed working in earlier steps. It never makes an API call (0 tokens in/out).

Our setup

• anthropics/claude-code-action@v1
• use_bedrock: true
• OIDC auth via aws-actions/configure-aws-credentials@v5.1.1
• Model: us.anthropic.claude-sonnet-4-5-20250929-v1:0
• Ubuntu 24.04 runner

What we've confirmed

• The OIDC step succeeds: Authenticated as a private assumed role from AWS IAM STS.

• AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_SESSION_TOKEN are all present in the env for subsequent steps

• Claude Code installs fine (v2.1.79), MCP servers connect

• The Bedrock env looks correct:
  CLAUDE_CODE_USE_BEDROCK: 1
  ANTHROPIC_BEDROCK_BASE_URL: https://bedrock-runtime.us-east-1.amazonaws.com

  But then:

  {
    "result": "API Error: Could not load credentials from any providers",
    "duration_api_ms": 0,
    "num_turns": 1,
    "usage": { "input_tokens": 0, "output_tokens": 0 }
  }

Here's our workflow config:

  - uses: anthropics/claude-code-action@v1
    with:
      use_bedrock: true
      claude_args: |
        --model us.anthropic.claude-sonnet-4-5-20250929-v1:0
        --max-turns 40

Timeline

This was working fine before yesterday. The only thing that changed on our end is the action auto-updating to v1.0.74+. Not sure if the issue is in the action itself or the Claude Code / Agent SDK versions it pulls in (v2.1.79 / v0.2.79).

Happy to provide the full run log if that helps. For now we're pinning to an older SHA as a workaround.

API Provider

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