diff --git a/action.yml b/action.yml
index 196a96c..9b7cc05 100644
--- a/action.yml
+++ b/action.yml
@@ -107,7 +107,8 @@ runs:
         GITHUB_TOKEN: ${{ github.token }}
         GITHUB_RUN_ID: ${{ github.run_id }}
         GITEA_API_URL: ${{ env.GITHUB_SERVER_URL }}
-        ANTHROPIC_API_KEY: ${{ inputs.anthropic_api_key }}
+        # Only set ANTHROPIC_API_KEY if not using OAuth
+        ANTHROPIC_API_KEY: ${{ inputs.anthropic_api_key != 'use-oauth' && inputs.anthropic_api_key || '' }}
         CLAUDE_CREDENTIALS: ${{ inputs.claude_credentials }}
 
     - name: Run Claude Code
@@ -135,7 +136,8 @@ runs:
         MCP_CONFIG: ${{ steps.prepare.outputs.mcp_config }}
         USE_BEDROCK: ${{ inputs.use_bedrock }}
         USE_VERTEX: ${{ inputs.use_vertex }}
-        ANTHROPIC_API_KEY: ${{ inputs.anthropic_api_key }}
+        # Only set ANTHROPIC_API_KEY if not using OAuth
+        ANTHROPIC_API_KEY: ${{ inputs.anthropic_api_key != 'use-oauth' && inputs.anthropic_api_key || '' }}
         CLAUDE_CREDENTIALS: ${{ inputs.claude_credentials }}
 
         # GitHub token for repository access