MCP GitHub comment tool fails to load, preventing Claude from updating PR comments with review content

[felipernb]

Bug Description:
The mcp__github_comment__update_claude_comment tool fails to load during execution, preventing Claude from posting its code review results to the GitHub PR comment. While the action
appears to "succeed", the actual review content is never posted to the PR.

Expected Behavior:

1. Claude should be able to use mcp__github_comment__update_claude_comment to update the PR comment with review findings
2. Users should see Claude's detailed code review posted as a comment on the PR
3. The comment should contain the actual review content, not just "Claude Code is working..."

Actual Behavior:

1. Claude receives an error when attempting to use the tool:
   Error: No such tool available: mcp__github_comment__update_claude_comment
2. Claude completes the analysis and writes a comprehensive review internally
3. However, the review content is never posted to the GitHub PR comment
4. The comment remains as just "Claude Code is working..." with a job link
5. Users cannot see Claude's actual review findings

Environment:

• Action version: anthropics/claude-code-action@v1
• Event type: pull_request
• Runner: ubuntu-24.04
• Claude model: claude-sonnet-4-20250514

Configuration:

  - name: Claude Code Review
    uses: anthropics/claude-code-action@v1
    with:
      claude_args: '--allowedTools "mcp__github_comment__update_claude_comment,mcp__github_inline_comment__create_inline_comment,Bash(gh pr comment:*),Bash(gh pr diff:*),Bash(gh pr
  view:*)"'

Evidence from Logs:

1. Tool not available:
   2025-09-06T21:03:20.6926960Z "content": "<tool_use_error>Error: No such tool available: mcp__github_comment__update_claude_comment</tool_use_error>",

2. MCP servers empty:
   2025-09-06T21:03:02.6619964Z "mcp_servers": [],

3. Claude completes analysis but cannot post review:

2025-09-06T21:05:29.5671945Z {"type":"assistant","message":{"content":[{"type":"text","text":"I cannot use the GitHub comment tool directly. Let me provide my comprehensive review
through the proper channel. Based on my analysis, I can now provide my code review findings:\n\n## Code Review: Google OAuth Integration\n\n### Overview\nThis PR migrates from
`expo-auth-session` to native OAuth SDKs...

4. Only job link gets updated:
   2025-09-06T21:05:35.1350787Z ✅ Updated issue comment 3263214042 with job link

Impact:

• Severity: High - core functionality broken
• Users cannot see Claude's code review results
• The action appears successful but provides no value
• Wastes API credits generating reviews that users never see

Expected vs Actual Comment Content:

Expected: Claude's detailed review with security findings, code quality assessment, recommendations, etc.

Actual: Just "Claude Code is working... I'll analyze this and get back to you. link"

Additional Context:

• Claude generates comprehensive, high-quality reviews internally (visible in logs)
• The issue is specifically with the comment update mechanism
• This makes the entire action essentially non-functional from a user perspective
• The update-comment-link.ts script only updates with job links, not review content

[austin-stell]

Any progress on this? I'm getting this issue as well. Any workarounds people are aware of? Thanks!

[scott-the-brewer]

Anyone else running into this issue.

From:

anthropics/claude-code-action@v1

To:

anthropics/claude-code-action@v1.0.3

This resolved it for us, we're able to get comments on the PR. Although, I haven't been able to get inline comments working.

[felipernb]

I commented

# track_progress: true

And now I get inline comments but not the general one.
Still using @v1

[BlackHole1]

Currently, there are two modes in claude-code-action: tag and agent.

According to the code at

claude-code-action/src/modes/detector.ts

Lines 20 to 25 in 1b7eb92

	// If track_progress is set for PR/issue events, force tag mode
	if (context.inputs.trackProgress && isEntityContext(context)) {
	if (isPullRequestEvent(context) || isIssuesEvent(context)) {
	return "tag";
	}
	}

, when track_progress is passed in, the mode will be forced to change to tag, rather than agent.

Claude-code-action will start some built-in mcp services, and its code can be found at:

claude-code-action/src/mcp/install-mcp-server.ts

Lines 50 to 67 in 1b7eb92

	export async function prepareMcpConfig(
	params: PrepareConfigParams,
	): Promise<string> {
	const {
	githubToken,
	owner,
	repo,
	branch,
	baseBranch,
	claudeCommentId,
	allowedTools,
	context,
	} = params;
	try {
	const allowedToolsList = allowedTools || [];
	// Detect if we're in agent mode (explicit prompt provided)
	const isAgentMode = !!context.inputs?.prompt;

.

In the above code, the check for whether it is in agent mode is different from what was mentioned before; here it only checks if the prompt exists.

So currently, when you pass in both track_progress and prompt, the entry point will change the mode to tag, but some internal code will still judge it as agent mode (I am uncertain if this is the expected behavior).

---

The above is some contextual information; below is the reason for the issue:

Since the mode is forced to become tag, it will execute:

claude-code-action/src/modes/tag/index.ts

Lines 115 to 132 in 1b7eb92

	// Get our GitHub MCP servers configuration
	const ourMcpConfig = await prepareMcpConfig({
	githubToken,
	owner: context.repository.owner,
	repo: context.repository.repo,
	branch: branchInfo.claudeBranch || branchInfo.currentBranch,
	baseBranch: branchInfo.baseBranch,
	claudeCommentId: commentId.toString(),
	allowedTools: [],
	context,
	});
	// Don't output mcp_config separately anymore - include in claude_args
	// Build claude_args for tag mode with required tools
	// Tag mode REQUIRES these tools to function properly
	const tagModeTools = [
	"Edit",

.

Note that the allowedTools here is an empty array, which should be the expected behavior according to the comments and surrounding code.

However, since an empty array is passed here, the following code will not run during the prepareMcpConfig check:

claude-code-action/src/mcp/install-mcp-server.ts

Lines 73 to 75 in 1b7eb92

	const hasInlineCommentTools = allowedToolsList.some((tool) =>
	tool.startsWith("mcp__github_inline_comment__"),
	);

claude-code-action/src/mcp/install-mcp-server.ts

Lines 130 to 150 in 1b7eb92

	// Include inline comment server for PRs when requested via allowed tools
	if (
	isEntityContext(context) &&
	context.isPR &&
	(hasGitHubMcpTools || hasInlineCommentTools)
	) {
	baseMcpConfig.mcpServers.github_inline_comment = {
	command: "bun",
	args: [
	"run",
	`${process.env.GITHUB_ACTION_PATH}/src/mcp/github-inline-comment-server.ts`,
	],
	env: {
	GITHUB_TOKEN: githubToken,
	REPO_OWNER: owner,
	REPO_NAME: repo,
	PR_NUMBER: context.entityNumber?.toString() || "",
	GITHUB_API_URL: GITHUB_API_URL,
	},
	};
	}

.

This leads to the github-inline-comment-server not being listed in the mcp config.

In the code:

claude-code-action/src/modes/tag/index.ts

Lines 164 to 179 in 1b7eb92

	const userClaudeArgs = process.env.CLAUDE_ARGS || "";
	// Build complete claude_args with multiple --mcp-config flags
	let claudeArgs = "";
	// Add our GitHub servers config
	const escapedOurConfig = ourMcpConfig.replace(/'/g, "'\\''");
	claudeArgs = `--mcp-config '${escapedOurConfig}'`;
	// Add required tools for tag mode
	claudeArgs += ` --allowedTools "${tagModeTools.join(",")}"`;
	// Append user's claude_args (which may have more --mcp-config flags)
	if (userClaudeArgs) {
	claudeArgs += ` ${userClaudeArgs}`;
	}

, the user’s input --allowedTools will be added to claudeArgs, so when you add mcp__github_inline_comment__create_inline_comment in --allowedTools, Claude thinks it can use this mcp. However, since it is not added to the mcp config, it ultimately results in: No such tool available: mcp__github_inline_comment__create_inline_comment.

The issue with mcp__github_comment__update_claude_comment is the same.

[ashwin-ant]

Addressing in #558

[ashwin-ant]

Fixed in 1.0.6

[arthurtaborda]

Hello @ashwin-ant, this is not fixed in 1.0.6, since the faulty code (https://github.com/anthropics/claude-code-action/pull/558/files#diff-193882c63302f6ad11ec1f7c0ae2f74e5faab7aaf7821123202c53b6eac681bdR123) is still there.

I confirmed I was using version 1.0.6, and with the inline comments MCP in the allowed tools:

- name: Trigger Claude Code
  uses: anthropics/claude-code-action@v1.0.6
  with:
      track_progress: true
      claude_args: |
        --model arn:aws:bedrock:us-east-1:340752820498:inference-profile/us.anthropic.claude-sonnet-4-20250514-v1:0
        --mcp-config /tmp/mcp-config.json
        --allowedTools "Bash(gh pr comment:*),
          Bash(gh pr view:*),
          Bash(git add:*),
          Bash(git commit:*),
          Bash(git push:*),
          Bash(git status:*),
          Bash(git rm:*),
          Bash(git log:*),
          Bash(ls:*),
          Edit,
          MultiEdit,
          Glob,
          Grep,
          LS,
          Read,
          Write,
          mcp__bedrock-kb,
          mcp__github_inline_comment__create_inline_comment"

[BlackHole1]

@arthurtaborda I checked the code, and #558 didn't really fix the issue... it can only be considered an optimization.

The root of the problem is at:

claude-code-action/src/modes/tag/index.ts

Line 123 in 1b7eb92

allowedTools: [],

I have clearly outlined the cause of the issue in #548 (comment), and I have submitted a related pull request. However, I am not sure why it has been ignored. 🤷

[ashwin-ant]

@BlackHole1 mind rebasing your PR? #556