feat: add workflow cancellation detection and update comment

When a workflow is cancelled, the comment now shows "Claude's task was cancelled" 
instead of the generic "Claude encountered an error" message. This provides clearer 
feedback to users about why the workflow stopped.

Changes:
- Add CLAUDE_CANCELLED environment variable using cancelled() function in action.yml
- Implement cancellation detection logic in update-comment-link.ts
- Update comment-logic.ts to show specific cancellation message
- Add comprehensive tests for cancellation handling

Fixes #123

Co-authored-by: ashwin-ant <ashwin-ant@users.noreply.github.com>

.github/workflows/issue-triage.yml

@@ -23,18 +23,20 @@ jobs:
           mkdir -p /tmp/mcp-config
           cat > /tmp/mcp-config/mcp-servers.json << 'EOF'
           {
-            "github": {
+            "mcpServers": {
-              "command": "docker",
+              "github": {
-              "args": [
+                "command": "docker",
-                "run",
+                "args": [
-                "-i",
+                  "run",
-                "--rm",
+                  "-i",
-                "-e",
+                  "--rm",
-                "GITHUB_PERSONAL_ACCESS_TOKEN",
+                  "-e",
-                "ghcr.io/github/github-mcp-server:sha-7aced2b"
+                  "GITHUB_PERSONAL_ACCESS_TOKEN",
-              ],
+                  "ghcr.io/github/github-mcp-server:sha-7aced2b"
-              "env": {
+                ],
-                "GITHUB_PERSONAL_ACCESS_TOKEN": "${{ secrets.GITHUB_TOKEN }}"
+                "env": {
+                  "GITHUB_PERSONAL_ACCESS_TOKEN": "${{ secrets.GITHUB_TOKEN }}"
+                }
               }
             }
           }

README.md

@@ -65,6 +65,11 @@ jobs:
           # trigger_phrase: "/claude"
           # Optional: add assignee trigger for issues
           # assignee_trigger: "claude"
+          # Optional: add custom environment variables (YAML format)
+          # claude_env: |
+          #   NODE_ENV: test
+          #   DEBUG: true
+          #   API_URL: https://api.example.com
 ```
 
 ## Inputs
@@ -82,13 +87,70 @@ jobs:
 | `allowed_tools`       | Additional tools for Claude to use (the base GitHub tools will always be included)                                   | No       | ""        |
 | `disallowed_tools`    | Tools that Claude should never use                                                                                   | No       | ""        |
 | `custom_instructions` | Additional custom instructions to include in the prompt for Claude                                                   | No       | ""        |
+| `mcp_config`          | Additional MCP configuration (JSON string) that merges with the built-in GitHub MCP servers                          | No       | ""        |
 | `assignee_trigger`    | The assignee username that triggers the action (e.g. @claude). Only used for issue assignment                        | No       | -         |
 | `trigger_phrase`      | The trigger phrase to look for in comments, issue/PR bodies, and issue titles                                        | No       | `@claude` |
+| `claude_env`          | Custom environment variables to pass to Claude Code execution (YAML format)                                          | No       | ""        |
 
 \*Required when using direct Anthropic API (default and when not using Bedrock or Vertex)
 
 > **Note**: This action is currently in beta. Features and APIs may change as we continue to improve the integration.
 
+### Using Custom MCP Configuration
+
+The `mcp_config` input allows you to add custom MCP (Model Context Protocol) servers to extend Claude's capabilities. These servers merge with the built-in GitHub MCP servers.
+
+#### Basic Example: Adding a Sequential Thinking Server
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    mcp_config: |
+      {
+        "mcpServers": {
+          "sequential-thinking": {
+            "command": "npx",
+            "args": [
+              "-y",
+              "@modelcontextprotocol/server-sequential-thinking"
+            ]
+          }
+        }
+      }
+    allowed_tools: "mcp__sequential-thinking__sequentialthinking" # Important: Each MCP tool from your server must be listed here, comma-separated
+    # ... other inputs
+```
+
+#### Passing Secrets to MCP Servers
+
+For MCP servers that require sensitive information like API keys or tokens, use GitHub Secrets in the environment variables:
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    mcp_config: |
+      {
+        "mcpServers": {
+          "custom-api-server": {
+            "command": "npx",
+            "args": ["-y", "@example/api-server"],
+            "env": {
+              "API_KEY": "${{ secrets.CUSTOM_API_KEY }}",
+              "BASE_URL": "https://api.example.com"
+            }
+          }
+        }
+      }
+    # ... other inputs
+```
+
+**Important**:
+
+- Always use GitHub Secrets (`${{ secrets.SECRET_NAME }}`) for sensitive values like API keys, tokens, or passwords. Never hardcode secrets directly in the workflow file.
+- Your custom servers will override any built-in servers with the same name.
+
 ## Examples
 
 ### Ways to Tag @claude
@@ -233,6 +295,22 @@ This action is built on top of [`anthropics/claude-code-base-action`](https://gi
 
 ## Advanced Configuration
 
+### Custom Environment Variables
+
+You can pass custom environment variables to Claude Code execution using the `claude_env` input. This is useful for CI/test setups that require specific environment variables:
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    claude_env: |
+      NODE_ENV: test
+      CI: true
+      DATABASE_URL: postgres://test:test@localhost:5432/test_db
+    # ... other inputs
+```
+
+The `claude_env` input accepts YAML format where each line defines a key-value pair. These environment variables will be available to Claude Code during execution, allowing it to run tests, build processes, or other commands that depend on specific environment configurations.
+
 ### Custom Tools
 
 By default, Claude only has access to:

action.yml

@@ -39,6 +39,12 @@ inputs:
     description: "Direct instruction for Claude (bypasses normal trigger detection)"
     required: false
     default: ""
+  mcp_config:
+    description: "Additional MCP configuration (JSON string) that merges with the built-in GitHub MCP servers"
+  claude_env:
+    description: "Custom environment variables to pass to Claude Code execution (YAML format)"
+    required: false
+    default: ""
 
   # Auth configuration
   anthropic_api_key:
@@ -92,13 +98,14 @@ runs:
         ALLOWED_TOOLS: ${{ inputs.allowed_tools }}
         CUSTOM_INSTRUCTIONS: ${{ inputs.custom_instructions }}
         DIRECT_PROMPT: ${{ inputs.direct_prompt }}
+        MCP_CONFIG: ${{ inputs.mcp_config }}
         OVERRIDE_GITHUB_TOKEN: ${{ inputs.github_token }}
         GITHUB_RUN_ID: ${{ github.run_id }}
 
     - name: Run Claude Code
       id: claude-code
       if: steps.prepare.outputs.contains_trigger == 'true'
-      uses: anthropics/claude-code-base-action@c8e31bd52d9a149b3f8309d7978c6edaa282688d # v0.0.8
+      uses: anthropics/claude-code-base-action@1370ac97fbba9bddec20ea2924b5726bf10d8b94 # v0.0.9
       with:
         prompt_file: /tmp/claude-prompts/claude-prompt.txt
         allowed_tools: ${{ env.ALLOWED_TOOLS }}
@@ -109,6 +116,7 @@ runs:
         use_bedrock: ${{ inputs.use_bedrock }}
         use_vertex: ${{ inputs.use_vertex }}
         anthropic_api_key: ${{ inputs.anthropic_api_key }}
+        claude_env: ${{ inputs.claude_env }}
       env:
         # Model configuration
         ANTHROPIC_MODEL: ${{ inputs.model || inputs.anthropic_model }}
@@ -152,6 +160,7 @@ runs:
         IS_PR: ${{ github.event.issue.pull_request != null || github.event_name == 'pull_request_review_comment' }}
         BASE_BRANCH: ${{ steps.prepare.outputs.BASE_BRANCH }}
         CLAUDE_SUCCESS: ${{ steps.claude-code.outputs.conclusion == 'success' }}
+        CLAUDE_CANCELLED: ${{ cancelled() }}
         OUTPUT_FILE: ${{ steps.claude-code.outputs.execution_file || '' }}
         TRIGGER_USERNAME: ${{ github.event.comment.user.login || github.event.issue.user.login || github.event.pull_request.user.login || github.event.sender.login || github.triggering_actor || github.actor || '' }}
         PREPARE_SUCCESS: ${{ steps.prepare.outcome == 'success' }}

src/create-prompt/index.ts

@@ -31,24 +31,13 @@ const BASE_ALLOWED_TOOLS = [
   "Write",
   "mcp__github_file_ops__commit_files",
   "mcp__github_file_ops__delete_files",
+  "mcp__github_file_ops__update_claude_comment",
 ];
 const DISALLOWED_TOOLS = ["WebSearch", "WebFetch"];
 
-export function buildAllowedToolsString(
+export function buildAllowedToolsString(customAllowedTools?: string): string {
-  eventData: EventData,
-  customAllowedTools?: string,
-): string {
   let baseTools = [...BASE_ALLOWED_TOOLS];
 
-  // Add the appropriate comment tool based on event type
-  if (eventData.eventName === "pull_request_review_comment") {
-    // For inline PR review comments, only use PR comment tool
-    baseTools.push("mcp__github__update_pull_request_comment");
-  } else {
-    // For all other events (issue comments, PR reviews, issues), use issue comment tool
-    baseTools.push("mcp__github__update_issue_comment");
-  }
-
   let allAllowedTools = baseTools.join(",");
   if (customAllowedTools) {
     allAllowedTools = `${allAllowedTools},${customAllowedTools}`;
@@ -447,33 +436,15 @@ ${sanitizeContent(context.directPrompt)}
 </direct_prompt>`
     : ""
 }
-${
+${`<comment_tool_info>
-  eventData.eventName === "pull_request_review_comment"
+IMPORTANT: You have been provided with the mcp__github_file_ops__update_claude_comment tool to update your comment. This tool automatically handles both issue and PR comments.
-    ? `<comment_tool_info>
-IMPORTANT: For this inline PR review comment, you have been provided with ONLY the mcp__github__update_pull_request_comment tool to update this specific review comment.
 
-Tool usage example for mcp__github__update_pull_request_comment:
+Tool usage example for mcp__github_file_ops__update_claude_comment:
 {
-  "owner": "${context.repository.split("/")[0]}",
-  "repo": "${context.repository.split("/")[1]}",
-  "commentId": ${eventData.commentId || context.claudeCommentId},
   "body": "Your comment text here"
 }
-All four parameters (owner, repo, commentId, body) are required.
+Only the body parameter is required - the tool automatically knows which comment to update.
-</comment_tool_info>`
+</comment_tool_info>`}
-    : `<comment_tool_info>
-IMPORTANT: For this event type, you have been provided with ONLY the mcp__github__update_issue_comment tool to update comments.
-
-Tool usage example for mcp__github__update_issue_comment:
-{
-  "owner": "${context.repository.split("/")[0]}",
-  "repo": "${context.repository.split("/")[1]}",
-  "commentId": ${context.claudeCommentId},
-  "body": "Your comment text here"
-}
-All four parameters (owner, repo, commentId, body) are required.
-</comment_tool_info>`
-}
 
 Your task is to analyze the context, understand the request, and provide helpful responses and/or implement code changes as needed.
 
@@ -487,7 +458,7 @@ Follow these steps:
 1. Create a Todo List:
    - Use your GitHub comment to maintain a detailed task list based on the request.
    - Format todos as a checklist (- [ ] for incomplete, - [x] for complete).
-   - Update the comment using ${eventData.eventName === "pull_request_review_comment" ? "mcp__github__update_pull_request_comment" : "mcp__github__update_issue_comment"} with each task completion.
+   - Update the comment using mcp__github_file_ops__update_claude_comment with each task completion.
 
 2. Gather Context:
    - Analyze the pre-fetched data provided above.
@@ -517,11 +488,11 @@ ${context.directPrompt ? `   - DIRECT INSTRUCTION: A direct instruction was prov
         - Look for bugs, security issues, performance problems, and other issues
         - Suggest improvements for readability and maintainability
         - Check for best practices and coding standards
-        - Reference specific code sections with file paths and line numbers${eventData.isPR ? "\n      - AFTER reading files and analyzing code, you MUST call mcp__github__update_issue_comment to post your review" : ""}
+        - Reference specific code sections with file paths and line numbers${eventData.isPR ? "\n      - AFTER reading files and analyzing code, you MUST call mcp__github_file_ops__update_claude_comment to post your review" : ""}
       - Formulate a concise, technical, and helpful response based on the context.
       - Reference specific code with inline formatting or code blocks.
       - Include relevant file paths and line numbers when applicable.
-      - ${eventData.isPR ? "IMPORTANT: Submit your review feedback by updating the Claude comment. This will be displayed as your PR review." : "Remember that this feedback must be posted to the GitHub comment."}
+      - ${eventData.isPR ? "IMPORTANT: Submit your review feedback by updating the Claude comment using mcp__github_file_ops__update_claude_comment. This will be displayed as your PR review." : "Remember that this feedback must be posted to the GitHub comment using mcp__github_file_ops__update_claude_comment."}
 
    B. For Straightforward Changes:
       - Use file system tools to make the change locally.
@@ -576,8 +547,8 @@ ${context.directPrompt ? `   - DIRECT INSTRUCTION: A direct instruction was prov
 
 Important Notes:
 - All communication must happen through GitHub PR comments.
-- Never create new comments. Only update the existing comment using ${eventData.eventName === "pull_request_review_comment" ? "mcp__github__update_pull_request_comment" : "mcp__github__update_issue_comment"} with comment_id: ${context.claudeCommentId}.
+- Never create new comments. Only update the existing comment using mcp__github_file_ops__update_claude_comment.
-- This includes ALL responses: code reviews, answers to questions, progress updates, and final results.${eventData.isPR ? "\n- PR CRITICAL: After reading files and forming your response, you MUST post it by calling mcp__github__update_issue_comment. Do NOT just respond with a normal response, the user will not see it." : ""}
+- This includes ALL responses: code reviews, answers to questions, progress updates, and final results.${eventData.isPR ? "\n- PR CRITICAL: After reading files and forming your response, you MUST post it by calling mcp__github_file_ops__update_claude_comment. Do NOT just respond with a normal response, the user will not see it." : ""}
 - You communicate exclusively by editing your single comment - not through any other means.
 - Use this spinner HTML when work is in progress: <img src="https://github.com/user-attachments/assets/5ac382c7-e004-429b-8e35-7feb3e8f9c6f" width="14px" height="14px" style="vertical-align: middle; margin-left: 4px;" />
 ${eventData.isPR && !eventData.claudeBranch ? `- Always push to the existing branch when triggered on a PR.` : `- IMPORTANT: You are already on the correct branch (${eventData.claudeBranch || "the created branch"}). Never create new branches when triggered on issues or closed/merged PRs.`}
@@ -665,7 +636,6 @@ export async function createPrompt(
 
     // Set allowed tools
     const allAllowedTools = buildAllowedToolsString(
-      preparedContext.eventData,
       preparedContext.allowedTools,
     );
     const allDisallowedTools = buildDisallowedToolsString(

src/entrypoints/prepare.ts

@@ -84,12 +84,15 @@ async function run() {
     );
 
     // Step 11: Get MCP configuration
-    const mcpConfig = await prepareMcpConfig(
+    const additionalMcpConfig = process.env.MCP_CONFIG || "";
+    const mcpConfig = await prepareMcpConfig({
       githubToken,
-      context.repository.owner,
+      owner: context.repository.owner,
-      context.repository.repo,
+      repo: context.repository.repo,
-      branchInfo.currentBranch,
+      branch: branchInfo.currentBranch,
-    );
+      additionalMcpConfig,
+      claudeCommentId: commentId.toString(),
+    });
     core.setOutput("mcp_config", mcpConfig);
   } catch (error) {
     const errorMessage = error instanceof Error ? error.message : String(error);

src/entrypoints/update-comment-link.ts

@@ -12,6 +12,7 @@ import {
 } from "../github/context";
 import { GITHUB_SERVER_URL } from "../github/api/config";
 import { checkAndDeleteEmptyBranch } from "../github/operations/branch-cleanup";
+import { updateClaudeComment } from "../github/operations/comments/update-claude-comment";
 
 async function run() {
   try {
@@ -145,8 +146,12 @@ async function run() {
       duration_api_ms?: number;
     } | null = null;
     let actionFailed = false;
+    let actionCancelled = false;
     let errorDetails: string | undefined;
 
+    // Check if the workflow was cancelled
+    const isCancelled = process.env.CLAUDE_CANCELLED === "true";
+
     // First check if prepare step failed
     const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
     const prepareError = process.env.PREPARE_ERROR;
@@ -154,8 +159,18 @@ async function run() {
     if (!prepareSuccess && prepareError) {
       actionFailed = true;
       errorDetails = prepareError;
+    } else if (isCancelled) {
+      // If the workflow was cancelled, set the cancelled flag
+      actionCancelled = true;
     } else {
-      // Check for existence of output file and parse it if available
+      // Check if the Claude action failed
+      // CLAUDE_SUCCESS is set to the result of: steps.claude-code.outputs.conclusion == 'success'
+      // If the step didn't run or didn't set outputs.conclusion, CLAUDE_SUCCESS will be "false"
+      // If the step succeeded, CLAUDE_SUCCESS will be "true"
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+
+      // Try to read execution details from output file
       try {
         const outputFile = process.env.OUTPUT_FILE;
         if (outputFile) {
@@ -178,14 +193,10 @@ async function run() {
             }
           }
         }
-
-        // Check if the Claude action failed
-        const claudeSuccess = process.env.CLAUDE_SUCCESS !== "false";
-        actionFailed = !claudeSuccess;
       } catch (error) {
         console.error("Error reading output file:", error);
-        // If we can't read the file, check for any failure markers
+        // Error reading output file doesn't change the action status
-        actionFailed = process.env.CLAUDE_SUCCESS === "false";
+        // We already determined actionFailed based on CLAUDE_SUCCESS
       }
     }
 
@@ -193,6 +204,7 @@ async function run() {
     const commentInput: CommentUpdateInput = {
       currentBody,
       actionFailed,
+      actionCancelled,
       executionDetails,
       jobUrl,
       branchLink,
@@ -204,23 +216,14 @@ async function run() {
 
     const updatedBody = updateCommentBody(commentInput);
 
-    // Update the comment using the appropriate API
     try {
-      if (isPRReviewComment) {
+      await updateClaudeComment(octokit.rest, {
-        await octokit.rest.pulls.updateReviewComment({
+        owner,
-          owner,
+        repo,
-          repo,
+        commentId,
-          comment_id: commentId,
+        body: updatedBody,
-          body: updatedBody,
+        isPullRequestReviewComment: isPRReviewComment,
-        });
+      });
-      } else {
-        await octokit.rest.issues.updateComment({
-          owner,
-          repo,
-          comment_id: commentId,
-          body: updatedBody,
-        });
-      }
       console.log(
         `✅ Updated ${isPRReviewComment ? "PR review" : "issue"} comment ${commentId} with job link`,
       );

src/github/data/fetcher.ts

@@ -1,17 +1,17 @@
 import { execSync } from "child_process";
+import type { Octokits } from "../api/client";
+import { ISSUE_QUERY, PR_QUERY } from "../api/queries/github";
 import type {
-  GitHubPullRequest,
-  GitHubIssue,
   GitHubComment,
   GitHubFile,
+  GitHubIssue,
+  GitHubPullRequest,
   GitHubReview,
-  PullRequestQueryResponse,
   IssueQueryResponse,
+  PullRequestQueryResponse,
 } from "../types";
-import { PR_QUERY, ISSUE_QUERY } from "../api/queries/github";
-import type { Octokits } from "../api/client";
-import { downloadCommentImages } from "../utils/image-downloader";
 import type { CommentWithImages } from "../utils/image-downloader";
+import { downloadCommentImages } from "../utils/image-downloader";
 
 type FetchDataParams = {
   octokits: Octokits;
@@ -101,6 +101,14 @@ export async function fetchGitHubData({
   let changedFilesWithSHA: GitHubFileWithSHA[] = [];
   if (isPR && changedFiles.length > 0) {
     changedFilesWithSHA = changedFiles.map((file) => {
+      // Don't compute SHA for deleted files
+      if (file.changeType === "DELETED") {
+        return {
+          ...file,
+          sha: "deleted",
+        };
+      }
+
       try {
         // Use git hash-object to compute the SHA for the current file content
         const sha = execSync(`git hash-object "${file.path}"`, {

src/github/operations/comment-logic.ts

@@ -9,6 +9,7 @@ export type ExecutionDetails = {
 export type CommentUpdateInput = {
   currentBody: string;
   actionFailed: boolean;
+  actionCancelled?: boolean;
   executionDetails: ExecutionDetails | null;
   jobUrl: string;
   branchLink?: string;
@@ -74,6 +75,7 @@ export function updateCommentBody(input: CommentUpdateInput): string {
     branchLink,
     prLink,
     actionFailed,
+    actionCancelled,
     branchName,
     triggerUsername,
     errorDetails,
@@ -112,7 +114,13 @@ export function updateCommentBody(input: CommentUpdateInput): string {
   // Build the header
   let header = "";
 
-  if (actionFailed) {
+  if (actionCancelled) {
+    header = "**Claude's task was cancelled";
+    if (durationStr) {
+      header += ` after ${durationStr}`;
+    }
+    header += "**";
+  } else if (actionFailed) {
     header = "**Claude encountered an error";
     if (durationStr) {
       header += ` after ${durationStr}`;

src/github/operations/comments/update-claude-comment.ts

@@ -0,0 +1,70 @@
+import { Octokit } from "@octokit/rest";
+
+export type UpdateClaudeCommentParams = {
+  owner: string;
+  repo: string;
+  commentId: number;
+  body: string;
+  isPullRequestReviewComment: boolean;
+};
+
+export type UpdateClaudeCommentResult = {
+  id: number;
+  html_url: string;
+  updated_at: string;
+};
+
+/**
+ * Updates a Claude comment on GitHub (either an issue/PR comment or a PR review comment)
+ *
+ * @param octokit - Authenticated Octokit instance
+ * @param params - Parameters for updating the comment
+ * @returns The updated comment details
+ * @throws Error if the update fails
+ */
+export async function updateClaudeComment(
+  octokit: Octokit,
+  params: UpdateClaudeCommentParams,
+): Promise<UpdateClaudeCommentResult> {
+  const { owner, repo, commentId, body, isPullRequestReviewComment } = params;
+
+  let response;
+
+  try {
+    if (isPullRequestReviewComment) {
+      // Try PR review comment API first
+      response = await octokit.rest.pulls.updateReviewComment({
+        owner,
+        repo,
+        comment_id: commentId,
+        body,
+      });
+    } else {
+      // Use issue comment API (works for both issues and PR general comments)
+      response = await octokit.rest.issues.updateComment({
+        owner,
+        repo,
+        comment_id: commentId,
+        body,
+      });
+    }
+  } catch (error: any) {
+    // If PR review comment update fails with 404, fall back to issue comment API
+    if (isPullRequestReviewComment && error.status === 404) {
+      response = await octokit.rest.issues.updateComment({
+        owner,
+        repo,
+        comment_id: commentId,
+        body,
+      });
+    } else {
+      throw error;
+    }
+  }
+
+  return {
+    id: response.data.id,
+    html_url: response.data.html_url,
+    updated_at: response.data.updated_at,
+  };
+}

src/github/operations/comments/update-with-branch.ts

@@ -15,6 +15,7 @@ import {
   isPullRequestReviewCommentEvent,
   type ParsedGitHubContext,
 } from "../../context";
+import { updateClaudeComment } from "./update-claude-comment";
 
 export async function updateTrackingComment(
   octokit: Octokits,
@@ -36,25 +37,19 @@ export async function updateTrackingComment(
 
   // Update the existing comment with the branch link
   try {
-    if (isPullRequestReviewCommentEvent(context)) {
+    const isPRReviewComment = isPullRequestReviewCommentEvent(context);
-      // For PR review comments (inline comments), use the pulls API
+
-      await octokit.rest.pulls.updateReviewComment({
+    await updateClaudeComment(octokit.rest, {
-        owner,
+      owner,
-        repo,
+      repo,
-        comment_id: commentId,
+      commentId,
-        body: updatedBody,
+      body: updatedBody,
-      });
+      isPullRequestReviewComment: isPRReviewComment,
-      console.log(`✅ Updated PR review comment ${commentId} with branch link`);
+    });
-    } else {
+
-      // For all other comments, use the issues API
+    console.log(
-      await octokit.rest.issues.updateComment({
+      `✅ Updated ${isPRReviewComment ? "PR review" : "issue"} comment ${commentId} with branch link`,
-        owner,
+    );
-        repo,
-        comment_id: commentId,
-        body: updatedBody,
-      });
-      console.log(`✅ Updated issue comment ${commentId} with branch link`);
-    }
   } catch (error) {
     console.error("Error updating comment with branch link:", error);
     throw error;

src/mcp/github-file-ops-server.ts

@@ -7,6 +7,8 @@ import { readFile } from "fs/promises";
 import { join } from "path";
 import fetch from "node-fetch";
 import { GITHUB_API_URL } from "../github/api/config";
+import { Octokit } from "@octokit/rest";
+import { updateClaudeComment } from "../github/operations/comments/update-claude-comment";
 
 type GitHubRef = {
   object: {
@@ -439,6 +441,69 @@ server.tool(
   },
 );
 
+server.tool(
+  "update_claude_comment",
+  "Update the Claude comment with progress and results (automatically handles both issue and PR comments)",
+  {
+    body: z.string().describe("The updated comment content"),
+  },
+  async ({ body }) => {
+    try {
+      const githubToken = process.env.GITHUB_TOKEN;
+      const claudeCommentId = process.env.CLAUDE_COMMENT_ID;
+      const eventName = process.env.GITHUB_EVENT_NAME;
+
+      if (!githubToken) {
+        throw new Error("GITHUB_TOKEN environment variable is required");
+      }
+      if (!claudeCommentId) {
+        throw new Error("CLAUDE_COMMENT_ID environment variable is required");
+      }
+
+      const owner = REPO_OWNER;
+      const repo = REPO_NAME;
+      const commentId = parseInt(claudeCommentId, 10);
+
+      const octokit = new Octokit({
+        auth: githubToken,
+      });
+
+      const isPullRequestReviewComment =
+        eventName === "pull_request_review_comment";
+
+      const result = await updateClaudeComment(octokit, {
+        owner,
+        repo,
+        commentId,
+        body,
+        isPullRequestReviewComment,
+      });
+
+      return {
+        content: [
+          {
+            type: "text",
+            text: JSON.stringify(result, null, 2),
+          },
+        ],
+      };
+    } catch (error) {
+      const errorMessage =
+        error instanceof Error ? error.message : String(error);
+      return {
+        content: [
+          {
+            type: "text",
+            text: `Error: ${errorMessage}`,
+          },
+        ],
+        error: errorMessage,
+        isError: true,
+      };
+    }
+  },
+);
+
 async function runServer() {
   const transport = new StdioServerTransport();
   await server.connect(transport);

src/mcp/install-mcp-server.ts

@@ -1,13 +1,27 @@
 import * as core from "@actions/core";
 
+type PrepareConfigParams = {
+  githubToken: string;
+  owner: string;
+  repo: string;
+  branch: string;
+  additionalMcpConfig?: string;
+  claudeCommentId?: string;
+};
+
 export async function prepareMcpConfig(
-  githubToken: string,
+  params: PrepareConfigParams,
-  owner: string,
-  repo: string,
-  branch: string,
 ): Promise<string> {
+  const {
+    githubToken,
+    owner,
+    repo,
+    branch,
+    additionalMcpConfig,
+    claudeCommentId,
+  } = params;
   try {
-    const mcpConfig = {
+    const baseMcpConfig = {
       mcpServers: {
         github: {
           command: "docker",
@@ -35,12 +49,47 @@ export async function prepareMcpConfig(
             REPO_NAME: repo,
             BRANCH_NAME: branch,
             REPO_DIR: process.env.GITHUB_WORKSPACE || process.cwd(),
+            ...(claudeCommentId && { CLAUDE_COMMENT_ID: claudeCommentId }),
+            GITHUB_EVENT_NAME: process.env.GITHUB_EVENT_NAME || "",
+            IS_PR: process.env.IS_PR || "false",
           },
         },
       },
     };
 
-    return JSON.stringify(mcpConfig, null, 2);
+    // Merge with additional MCP config if provided
+    if (additionalMcpConfig && additionalMcpConfig.trim()) {
+      try {
+        const additionalConfig = JSON.parse(additionalMcpConfig);
+
+        // Validate that parsed JSON is an object
+        if (typeof additionalConfig !== "object" || additionalConfig === null) {
+          throw new Error("MCP config must be a valid JSON object");
+        }
+
+        core.info(
+          "Merging additional MCP server configuration with built-in servers",
+        );
+
+        // Merge configurations with user config overriding built-in servers
+        const mergedConfig = {
+          ...baseMcpConfig,
+          ...additionalConfig,
+          mcpServers: {
+            ...baseMcpConfig.mcpServers,
+            ...additionalConfig.mcpServers,
+          },
+        };
+
+        return JSON.stringify(mergedConfig, null, 2);
+      } catch (parseError) {
+        core.warning(
+          `Failed to parse additional MCP config: ${parseError}. Using base config only.`,
+        );
+      }
+    }
+
+    return JSON.stringify(baseMcpConfig, null, 2);
   } catch (error) {
     core.setFailed(`Install MCP server failed with error: ${error}`);
     process.exit(1);

test/comment-logic.test.ts

@@ -418,4 +418,48 @@ describe("updateCommentBody", () => {
       );
     });
   });
+
+  describe("cancellation handling", () => {
+    it("shows cancellation message when actionCancelled is true", () => {
+      const input = {
+        ...baseInput,
+        currentBody: "Claude Code is working…",
+        actionCancelled: true,
+        executionDetails: { duration_ms: 30000 }, // 30s
+        triggerUsername: "test-user",
+      };
+
+      const result = updateCommentBody(input);
+      expect(result).toContain("**Claude's task was cancelled after 30s**");
+      expect(result).not.toContain("Claude encountered an error");
+      expect(result).not.toContain("Claude finished");
+    });
+
+    it("shows cancellation message without duration when duration is missing", () => {
+      const input = {
+        ...baseInput,
+        currentBody: "Claude Code is working…",
+        actionCancelled: true,
+        triggerUsername: "test-user",
+      };
+
+      const result = updateCommentBody(input);
+      expect(result).toContain("**Claude's task was cancelled**");
+      expect(result).not.toContain("after");
+    });
+
+    it("prioritizes cancellation over failure", () => {
+      const input = {
+        ...baseInput,
+        currentBody: "Claude Code is working…",
+        actionCancelled: true,
+        actionFailed: true, // Both are true, cancellation should take precedence
+        executionDetails: { duration_ms: 45000 },
+      };
+
+      const result = updateCommentBody(input);
+      expect(result).toContain("**Claude's task was cancelled after 45s**");
+      expect(result).not.toContain("Claude encountered an error");
+    });
+  });
 });

test/create-prompt.test.ts

@@ -8,7 +8,6 @@ import {
   buildDisallowedToolsString,
 } from "../src/create-prompt";
 import type { PreparedContext } from "../src/create-prompt";
-import type { EventData } from "../src/create-prompt/types";
 
 describe("generatePrompt", () => {
   const mockGitHubData = {
@@ -619,15 +618,7 @@ describe("getEventTypeAndContext", () => {
 
 describe("buildAllowedToolsString", () => {
   test("should return issue comment tool for regular events", () => {
-    const mockEventData: EventData = {
+    const result = buildAllowedToolsString();
-      eventName: "issue_comment",
-      commentId: "123",
-      isPR: true,
-      prNumber: "456",
-      commentBody: "Test comment",
-    };
-
-    const result = buildAllowedToolsString(mockEventData);
 
     // The base tools should be in the result
     expect(result).toContain("Edit");
@@ -636,22 +627,15 @@ describe("buildAllowedToolsString", () => {
     expect(result).toContain("LS");
     expect(result).toContain("Read");
     expect(result).toContain("Write");
-    expect(result).toContain("mcp__github__update_issue_comment");
+    expect(result).toContain("mcp__github_file_ops__update_claude_comment");
+    expect(result).not.toContain("mcp__github__update_issue_comment");
     expect(result).not.toContain("mcp__github__update_pull_request_comment");
     expect(result).toContain("mcp__github_file_ops__commit_files");
     expect(result).toContain("mcp__github_file_ops__delete_files");
   });
 
   test("should return PR comment tool for inline review comments", () => {
-    const mockEventData: EventData = {
+    const result = buildAllowedToolsString();
-      eventName: "pull_request_review_comment",
-      isPR: true,
-      prNumber: "456",
-      commentBody: "Test review comment",
-      commentId: "789",
-    };
-
-    const result = buildAllowedToolsString(mockEventData);
 
     // The base tools should be in the result
     expect(result).toContain("Edit");
@@ -660,23 +644,16 @@ describe("buildAllowedToolsString", () => {
     expect(result).toContain("LS");
     expect(result).toContain("Read");
     expect(result).toContain("Write");
+    expect(result).toContain("mcp__github_file_ops__update_claude_comment");
     expect(result).not.toContain("mcp__github__update_issue_comment");
-    expect(result).toContain("mcp__github__update_pull_request_comment");
+    expect(result).not.toContain("mcp__github__update_pull_request_comment");
     expect(result).toContain("mcp__github_file_ops__commit_files");
     expect(result).toContain("mcp__github_file_ops__delete_files");
   });
 
   test("should append custom tools when provided", () => {
-    const mockEventData: EventData = {
-      eventName: "issue_comment",
-      commentId: "123",
-      isPR: true,
-      prNumber: "456",
-      commentBody: "Test comment",
-    };
-
     const customTools = "Tool1,Tool2,Tool3";
-    const result = buildAllowedToolsString(mockEventData, customTools);
+    const result = buildAllowedToolsString(customTools);
 
     // Base tools should be present
     expect(result).toContain("Edit");

test/install-mcp-server.test.ts

@@ -0,0 +1,344 @@
+import { describe, test, expect, beforeEach, afterEach, spyOn } from "bun:test";
+import { prepareMcpConfig } from "../src/mcp/install-mcp-server";
+import * as core from "@actions/core";
+
+describe("prepareMcpConfig", () => {
+  let consoleInfoSpy: any;
+  let consoleWarningSpy: any;
+  let setFailedSpy: any;
+  let processExitSpy: any;
+
+  beforeEach(() => {
+    consoleInfoSpy = spyOn(core, "info").mockImplementation(() => {});
+    consoleWarningSpy = spyOn(core, "warning").mockImplementation(() => {});
+    setFailedSpy = spyOn(core, "setFailed").mockImplementation(() => {});
+    processExitSpy = spyOn(process, "exit").mockImplementation(() => {
+      throw new Error("Process exit");
+    });
+  });
+
+  afterEach(() => {
+    consoleInfoSpy.mockRestore();
+    consoleWarningSpy.mockRestore();
+    setFailedSpy.mockRestore();
+    processExitSpy.mockRestore();
+  });
+
+  test("should return base config when no additional config is provided", async () => {
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.mcpServers).toBeDefined();
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+    expect(parsed.mcpServers.github.env.GITHUB_PERSONAL_ACCESS_TOKEN).toBe(
+      "test-token",
+    );
+    expect(parsed.mcpServers.github_file_ops.env.GITHUB_TOKEN).toBe(
+      "test-token",
+    );
+    expect(parsed.mcpServers.github_file_ops.env.REPO_OWNER).toBe("test-owner");
+    expect(parsed.mcpServers.github_file_ops.env.REPO_NAME).toBe("test-repo");
+    expect(parsed.mcpServers.github_file_ops.env.BRANCH_NAME).toBe(
+      "test-branch",
+    );
+  });
+
+  test("should return base config when additional config is empty string", async () => {
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: "",
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.mcpServers).toBeDefined();
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+    expect(consoleWarningSpy).not.toHaveBeenCalled();
+  });
+
+  test("should return base config when additional config is whitespace only", async () => {
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: "   \n\t  ",
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.mcpServers).toBeDefined();
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+    expect(consoleWarningSpy).not.toHaveBeenCalled();
+  });
+
+  test("should merge valid additional config with base config", async () => {
+    const additionalConfig = JSON.stringify({
+      mcpServers: {
+        custom_server: {
+          command: "custom-command",
+          args: ["arg1", "arg2"],
+          env: {
+            CUSTOM_ENV: "custom-value",
+          },
+        },
+      },
+    });
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: additionalConfig,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(consoleInfoSpy).toHaveBeenCalledWith(
+      "Merging additional MCP server configuration with built-in servers",
+    );
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+    expect(parsed.mcpServers.custom_server).toBeDefined();
+    expect(parsed.mcpServers.custom_server.command).toBe("custom-command");
+    expect(parsed.mcpServers.custom_server.args).toEqual(["arg1", "arg2"]);
+    expect(parsed.mcpServers.custom_server.env.CUSTOM_ENV).toBe("custom-value");
+  });
+
+  test("should override built-in servers when additional config has same server names", async () => {
+    const additionalConfig = JSON.stringify({
+      mcpServers: {
+        github: {
+          command: "overridden-command",
+          args: ["overridden-arg"],
+          env: {
+            OVERRIDDEN_ENV: "overridden-value",
+          },
+        },
+      },
+    });
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: additionalConfig,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(consoleInfoSpy).toHaveBeenCalledWith(
+      "Merging additional MCP server configuration with built-in servers",
+    );
+    expect(parsed.mcpServers.github.command).toBe("overridden-command");
+    expect(parsed.mcpServers.github.args).toEqual(["overridden-arg"]);
+    expect(parsed.mcpServers.github.env.OVERRIDDEN_ENV).toBe(
+      "overridden-value",
+    );
+    expect(
+      parsed.mcpServers.github.env.GITHUB_PERSONAL_ACCESS_TOKEN,
+    ).toBeUndefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+  });
+
+  test("should merge additional root-level properties", async () => {
+    const additionalConfig = JSON.stringify({
+      customProperty: "custom-value",
+      anotherProperty: {
+        nested: "value",
+      },
+      mcpServers: {
+        custom_server: {
+          command: "custom",
+        },
+      },
+    });
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: additionalConfig,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.customProperty).toBe("custom-value");
+    expect(parsed.anotherProperty).toEqual({ nested: "value" });
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.custom_server).toBeDefined();
+  });
+
+  test("should handle invalid JSON gracefully", async () => {
+    const invalidJson = "{ invalid json }";
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: invalidJson,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(consoleWarningSpy).toHaveBeenCalledWith(
+      expect.stringContaining("Failed to parse additional MCP config:"),
+    );
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+  });
+
+  test("should handle non-object JSON values", async () => {
+    const nonObjectJson = JSON.stringify("string value");
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: nonObjectJson,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(consoleWarningSpy).toHaveBeenCalledWith(
+      expect.stringContaining("Failed to parse additional MCP config:"),
+    );
+    expect(consoleWarningSpy).toHaveBeenCalledWith(
+      expect.stringContaining("MCP config must be a valid JSON object"),
+    );
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+  });
+
+  test("should handle null JSON value", async () => {
+    const nullJson = JSON.stringify(null);
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: nullJson,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(consoleWarningSpy).toHaveBeenCalledWith(
+      expect.stringContaining("Failed to parse additional MCP config:"),
+    );
+    expect(consoleWarningSpy).toHaveBeenCalledWith(
+      expect.stringContaining("MCP config must be a valid JSON object"),
+    );
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+  });
+
+  test("should handle array JSON value", async () => {
+    const arrayJson = JSON.stringify([1, 2, 3]);
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: arrayJson,
+    });
+
+    const parsed = JSON.parse(result);
+    // Arrays are objects in JavaScript, so they pass the object check
+    // But they'll fail when trying to spread or access mcpServers property
+    expect(consoleInfoSpy).toHaveBeenCalledWith(
+      "Merging additional MCP server configuration with built-in servers",
+    );
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops).toBeDefined();
+    // The array will be spread into the config (0: 1, 1: 2, 2: 3)
+    expect(parsed[0]).toBe(1);
+    expect(parsed[1]).toBe(2);
+    expect(parsed[2]).toBe(3);
+  });
+
+  test("should merge complex nested configurations", async () => {
+    const additionalConfig = JSON.stringify({
+      mcpServers: {
+        server1: {
+          command: "cmd1",
+          env: { KEY1: "value1" },
+        },
+        server2: {
+          command: "cmd2",
+          env: { KEY2: "value2" },
+        },
+        github_file_ops: {
+          command: "overridden",
+          env: { CUSTOM: "value" },
+        },
+      },
+      otherConfig: {
+        nested: {
+          deeply: "value",
+        },
+      },
+    });
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+      additionalMcpConfig: additionalConfig,
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.mcpServers.server1).toBeDefined();
+    expect(parsed.mcpServers.server2).toBeDefined();
+    expect(parsed.mcpServers.github).toBeDefined();
+    expect(parsed.mcpServers.github_file_ops.command).toBe("overridden");
+    expect(parsed.mcpServers.github_file_ops.env.CUSTOM).toBe("value");
+    expect(parsed.otherConfig.nested.deeply).toBe("value");
+  });
+
+  test("should preserve GITHUB_ACTION_PATH in file_ops server args", async () => {
+    const oldEnv = process.env.GITHUB_ACTION_PATH;
+    process.env.GITHUB_ACTION_PATH = "/test/action/path";
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.mcpServers.github_file_ops.args[1]).toBe(
+      "/test/action/path/src/mcp/github-file-ops-server.ts",
+    );
+
+    process.env.GITHUB_ACTION_PATH = oldEnv;
+  });
+
+  test("should use process.cwd() when GITHUB_WORKSPACE is not set", async () => {
+    const oldEnv = process.env.GITHUB_WORKSPACE;
+    delete process.env.GITHUB_WORKSPACE;
+
+    const result = await prepareMcpConfig({
+      githubToken: "test-token",
+      owner: "test-owner",
+      repo: "test-repo",
+      branch: "test-branch",
+    });
+
+    const parsed = JSON.parse(result);
+    expect(parsed.mcpServers.github_file_ops.env.REPO_DIR).toBe(process.cwd());
+
+    process.env.GITHUB_WORKSPACE = oldEnv;
+  });
+});

test/update-claude-comment.test.ts

@@ -0,0 +1,413 @@
+import { describe, test, expect, jest, beforeEach } from "bun:test";
+import { Octokit } from "@octokit/rest";
+import {
+  updateClaudeComment,
+  type UpdateClaudeCommentParams,
+} from "../src/github/operations/comments/update-claude-comment";
+
+describe("updateClaudeComment", () => {
+  let mockOctokit: Octokit;
+
+  beforeEach(() => {
+    mockOctokit = {
+      rest: {
+        issues: {
+          updateComment: jest.fn(),
+        },
+        pulls: {
+          updateReviewComment: jest.fn(),
+        },
+      },
+    } as any as Octokit;
+  });
+
+  test("should update issue comment successfully", async () => {
+    const mockResponse = {
+      data: {
+        id: 123456,
+        html_url: "https://github.com/owner/repo/issues/1#issuecomment-123456",
+        updated_at: "2024-01-01T00:00:00Z",
+        body: "Updated comment",
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 123456,
+      body: "Updated comment",
+      isPullRequestReviewComment: false,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(mockOctokit.rest.issues.updateComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 123456,
+      body: "Updated comment",
+    });
+
+    expect(result).toEqual({
+      id: 123456,
+      html_url: "https://github.com/owner/repo/issues/1#issuecomment-123456",
+      updated_at: "2024-01-01T00:00:00Z",
+    });
+  });
+
+  test("should update PR comment successfully", async () => {
+    const mockResponse = {
+      data: {
+        id: 789012,
+        html_url: "https://github.com/owner/repo/pull/2#issuecomment-789012",
+        updated_at: "2024-01-02T00:00:00Z",
+        body: "Updated PR comment",
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 789012,
+      body: "Updated PR comment",
+      isPullRequestReviewComment: false,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(mockOctokit.rest.issues.updateComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 789012,
+      body: "Updated PR comment",
+    });
+
+    expect(result).toEqual({
+      id: 789012,
+      html_url: "https://github.com/owner/repo/pull/2#issuecomment-789012",
+      updated_at: "2024-01-02T00:00:00Z",
+    });
+  });
+
+  test("should update PR review comment successfully", async () => {
+    const mockResponse = {
+      data: {
+        id: 345678,
+        html_url: "https://github.com/owner/repo/pull/3#discussion_r345678",
+        updated_at: "2024-01-03T00:00:00Z",
+        body: "Updated review comment",
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.pulls.updateReviewComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 345678,
+      body: "Updated review comment",
+      isPullRequestReviewComment: true,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(mockOctokit.rest.pulls.updateReviewComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 345678,
+      body: "Updated review comment",
+    });
+
+    expect(result).toEqual({
+      id: 345678,
+      html_url: "https://github.com/owner/repo/pull/3#discussion_r345678",
+      updated_at: "2024-01-03T00:00:00Z",
+    });
+  });
+
+  test("should fallback to issue comment API when PR review comment update fails with 404", async () => {
+    const mockError = new Error("Not Found") as any;
+    mockError.status = 404;
+
+    const mockResponse = {
+      data: {
+        id: 456789,
+        html_url: "https://github.com/owner/repo/pull/4#issuecomment-456789",
+        updated_at: "2024-01-04T00:00:00Z",
+        body: "Updated via fallback",
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.pulls.updateReviewComment = jest
+      .fn()
+      .mockRejectedValue(mockError);
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 456789,
+      body: "Updated via fallback",
+      isPullRequestReviewComment: true,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(mockOctokit.rest.pulls.updateReviewComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 456789,
+      body: "Updated via fallback",
+    });
+
+    expect(mockOctokit.rest.issues.updateComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 456789,
+      body: "Updated via fallback",
+    });
+
+    expect(result).toEqual({
+      id: 456789,
+      html_url: "https://github.com/owner/repo/pull/4#issuecomment-456789",
+      updated_at: "2024-01-04T00:00:00Z",
+    });
+  });
+
+  test("should propagate error when PR review comment update fails with non-404 error", async () => {
+    const mockError = new Error("Internal Server Error") as any;
+    mockError.status = 500;
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.pulls.updateReviewComment = jest
+      .fn()
+      .mockRejectedValue(mockError);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 567890,
+      body: "This will fail",
+      isPullRequestReviewComment: true,
+    };
+
+    await expect(updateClaudeComment(mockOctokit, params)).rejects.toEqual(
+      mockError,
+    );
+
+    expect(mockOctokit.rest.pulls.updateReviewComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 567890,
+      body: "This will fail",
+    });
+
+    // Ensure fallback wasn't attempted
+    expect(mockOctokit.rest.issues.updateComment).not.toHaveBeenCalled();
+  });
+
+  test("should propagate error when issue comment update fails", async () => {
+    const mockError = new Error("Forbidden");
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockRejectedValue(mockError);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 678901,
+      body: "This will also fail",
+      isPullRequestReviewComment: false,
+    };
+
+    await expect(updateClaudeComment(mockOctokit, params)).rejects.toEqual(
+      mockError,
+    );
+
+    expect(mockOctokit.rest.issues.updateComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 678901,
+      body: "This will also fail",
+    });
+  });
+
+  test("should handle empty body", async () => {
+    const mockResponse = {
+      data: {
+        id: 111222,
+        html_url: "https://github.com/owner/repo/issues/5#issuecomment-111222",
+        updated_at: "2024-01-05T00:00:00Z",
+        body: "",
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 111222,
+      body: "",
+      isPullRequestReviewComment: false,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(result).toEqual({
+      id: 111222,
+      html_url: "https://github.com/owner/repo/issues/5#issuecomment-111222",
+      updated_at: "2024-01-05T00:00:00Z",
+    });
+  });
+
+  test("should handle very long body", async () => {
+    const longBody = "x".repeat(10000);
+    const mockResponse = {
+      data: {
+        id: 333444,
+        html_url: "https://github.com/owner/repo/issues/6#issuecomment-333444",
+        updated_at: "2024-01-06T00:00:00Z",
+        body: longBody,
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 333444,
+      body: longBody,
+      isPullRequestReviewComment: false,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(mockOctokit.rest.issues.updateComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 333444,
+      body: longBody,
+    });
+
+    expect(result).toEqual({
+      id: 333444,
+      html_url: "https://github.com/owner/repo/issues/6#issuecomment-333444",
+      updated_at: "2024-01-06T00:00:00Z",
+    });
+  });
+
+  test("should handle markdown formatting in body", async () => {
+    const markdownBody = `
+# Header
+- List item 1
+- List item 2
+
+\`\`\`typescript
+const code = "example";
+\`\`\`
+
+[Link](https://example.com)
+    `.trim();
+
+    const mockResponse = {
+      data: {
+        id: 555666,
+        html_url: "https://github.com/owner/repo/issues/7#issuecomment-555666",
+        updated_at: "2024-01-07T00:00:00Z",
+        body: markdownBody,
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.issues.updateComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 555666,
+      body: markdownBody,
+      isPullRequestReviewComment: false,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    expect(mockOctokit.rest.issues.updateComment).toHaveBeenCalledWith({
+      owner: "testowner",
+      repo: "testrepo",
+      comment_id: 555666,
+      body: markdownBody,
+    });
+
+    expect(result).toEqual({
+      id: 555666,
+      html_url: "https://github.com/owner/repo/issues/7#issuecomment-555666",
+      updated_at: "2024-01-07T00:00:00Z",
+    });
+  });
+
+  test("should handle different response data fields", async () => {
+    const mockResponse = {
+      data: {
+        id: 777888,
+        html_url: "https://github.com/owner/repo/pull/8#discussion_r777888",
+        updated_at: "2024-01-08T12:30:45Z",
+        body: "Updated",
+        // Additional fields that might be in the response
+        created_at: "2024-01-01T00:00:00Z",
+        user: { login: "bot" },
+        node_id: "MDI0OlB1bGxSZXF1ZXN0UmV2aWV3Q29tbWVudDc3Nzg4OA==",
+      },
+    };
+
+    // @ts-expect-error Mock implementation doesn't match full type signature
+    mockOctokit.rest.pulls.updateReviewComment = jest
+      .fn()
+      .mockResolvedValue(mockResponse);
+
+    const params: UpdateClaudeCommentParams = {
+      owner: "testowner",
+      repo: "testrepo",
+      commentId: 777888,
+      body: "Updated",
+      isPullRequestReviewComment: true,
+    };
+
+    const result = await updateClaudeComment(mockOctokit, params);
+
+    // Should only return the specific fields we care about
+    expect(result).toEqual({
+      id: 777888,
+      html_url: "https://github.com/owner/repo/pull/8#discussion_r777888",
+      updated_at: "2024-01-08T12:30:45Z",
+    });
+  });
+});

test/update-comment-link-logic.test.ts

@@ -0,0 +1,160 @@
+import { describe, test, expect, beforeEach, afterEach } from "bun:test";
+
+describe("update-comment-link workflow status detection", () => {
+  let originalEnv: NodeJS.ProcessEnv;
+
+  beforeEach(() => {
+    originalEnv = { ...process.env };
+  });
+
+  afterEach(() => {
+    process.env = originalEnv;
+  });
+
+  test("should detect prepare step failure", () => {
+    process.env.PREPARE_SUCCESS = "false";
+    process.env.PREPARE_ERROR = "Failed to fetch issue data";
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+
+    let actionFailed = false;
+    let errorDetails: string | undefined;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+      errorDetails = prepareError;
+    }
+
+    expect(actionFailed).toBe(true);
+    expect(errorDetails).toBe("Failed to fetch issue data");
+  });
+
+  test("should detect claude-code step failure when prepare succeeds", () => {
+    process.env.PREPARE_SUCCESS = "true";
+    process.env.CLAUDE_SUCCESS = "false";
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+
+    let actionFailed = false;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+    } else {
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+    }
+
+    expect(actionFailed).toBe(true);
+  });
+
+  test("should detect success when both steps succeed", () => {
+    process.env.PREPARE_SUCCESS = "true";
+    process.env.CLAUDE_SUCCESS = "true";
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+
+    let actionFailed = false;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+    } else {
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+    }
+
+    expect(actionFailed).toBe(false);
+  });
+
+  test("should treat missing CLAUDE_SUCCESS env var as failure", () => {
+    process.env.PREPARE_SUCCESS = "true";
+    delete process.env.CLAUDE_SUCCESS;
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+
+    let actionFailed = false;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+    } else {
+      // When CLAUDE_SUCCESS is undefined, it's not === "true", so claudeSuccess = false
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+    }
+
+    expect(actionFailed).toBe(true);
+  });
+
+  test("should handle undefined PREPARE_SUCCESS as success", () => {
+    delete process.env.PREPARE_SUCCESS;
+    delete process.env.PREPARE_ERROR;
+    process.env.CLAUDE_SUCCESS = "true";
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+
+    let actionFailed = false;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+    } else {
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+    }
+
+    expect(actionFailed).toBe(false);
+  });
+
+  test("should detect cancellation when CLAUDE_CANCELLED is true", () => {
+    process.env.PREPARE_SUCCESS = "true";
+    process.env.CLAUDE_SUCCESS = "false";
+    process.env.CLAUDE_CANCELLED = "true";
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+    const isCancelled = process.env.CLAUDE_CANCELLED === "true";
+
+    let actionFailed = false;
+    let actionCancelled = false;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+    } else if (isCancelled) {
+      actionCancelled = true;
+    } else {
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+    }
+
+    expect(actionFailed).toBe(false);
+    expect(actionCancelled).toBe(true);
+  });
+
+  test("should not detect cancellation when CLAUDE_CANCELLED is false", () => {
+    process.env.PREPARE_SUCCESS = "true";
+    process.env.CLAUDE_SUCCESS = "false";
+    process.env.CLAUDE_CANCELLED = "false";
+
+    const prepareSuccess = process.env.PREPARE_SUCCESS !== "false";
+    const prepareError = process.env.PREPARE_ERROR;
+    const isCancelled = process.env.CLAUDE_CANCELLED === "true";
+
+    let actionFailed = false;
+    let actionCancelled = false;
+
+    if (!prepareSuccess && prepareError) {
+      actionFailed = true;
+    } else if (isCancelled) {
+      actionCancelled = true;
+    } else {
+      const claudeSuccess = process.env.CLAUDE_SUCCESS === "true";
+      actionFailed = !claudeSuccess;
+    }
+
+    expect(actionFailed).toBe(true);
+    expect(actionCancelled).toBe(false);
+  });
+});