fix: use word-boundary lookbehind/lookahead for trigger phrase matching

docs/faq.md

@@ -209,9 +209,9 @@ However, tools from these servers still need to be explicitly allowed via `claud
 
 Check the GitHub Action log for Claude's run for the full execution trace.
 
-### Why can't I trigger Claude with `@claude-mention` or `claude!`?
+### Why can't I trigger Claude with `@claude-mention` or `claude@mention`?
 
-The trigger uses word boundaries, so `@claude` must be a complete word. Variations like `@claude-bot`, `@claude!`, or `claude@mention` won't work unless you customize the `trigger_phrase`.
+The trigger uses word boundaries, so `@claude` must not be embedded inside a word. Variations like `@claude-bot` or `claude@mention` won't work unless you customize the `trigger_phrase`. However, any non-word character around the trigger phrase is supported—`@claude!`, `(@claude)`, `"@claude"`, `>@claude`, `cc:@claude`, and `` `@claude` `` will all trigger correctly. The matching is also case-insensitive, so `@Claude` and `@CLAUDE` work too.
 
 ### How can I use custom executables in specialized environments?
 

src/github/validation/trigger.ts

@@ -11,6 +11,19 @@ import {
 } from "../context";
 import type { ParsedGitHubContext } from "../context";
 
+/**
+ * Build a regex that matches the trigger phrase only when it appears as a
+ * standalone token — i.e. not embedded inside a word like "email@claude.com"
+ * or a hyphenated username like "@claude-bot".
+ *
+ * Uses negative lookbehind/lookahead for word characters and hyphens so that
+ * any other character (punctuation, brackets, quotes, etc.) is accepted as a
+ * boundary without needing an explicit allowlist.
+ */
+function buildTriggerRegex(triggerPhrase: string): RegExp {
+  return new RegExp(`(?<![\\w-])${escapeRegExp(triggerPhrase)}(?![\\w-])`, "i");
+}
+
 export function checkContainsTrigger(context: ParsedGitHubContext): boolean {
   const {
     inputs: { assigneeTrigger, labelTrigger, triggerPhrase, prompt },
@@ -24,7 +37,7 @@ export function checkContainsTrigger(context: ParsedGitHubContext): boolean {
 
   // Check for assignee trigger
   if (isIssuesAssignedEvent(context)) {
-    // Remove @ symbol from assignee_trigger if present
+    // Remove @ symbol from assignee trigger if present
     let triggerUser = assigneeTrigger.replace(/^@/, "");
     const assigneeUsername = context.payload.assignee?.login || "";
 
@@ -48,10 +61,7 @@ export function checkContainsTrigger(context: ParsedGitHubContext): boolean {
   if (isIssuesEvent(context) && context.eventAction === "opened") {
     const issueBody = context.payload.issue.body || "";
     const issueTitle = context.payload.issue.title || "";
-    // Check for exact match with word boundaries or punctuation
-    const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
-    );
+    const regex = buildTriggerRegex(triggerPhrase);
 
     // Check in body
     if (regex.test(issueBody)) {
@@ -74,10 +84,7 @@ export function checkContainsTrigger(context: ParsedGitHubContext): boolean {
   if (isPullRequestEvent(context)) {
     const prBody = context.payload.pull_request.body || "";
     const prTitle = context.payload.pull_request.title || "";
-    // Check for exact match with word boundaries or punctuation
-    const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
-    );
+    const regex = buildTriggerRegex(triggerPhrase);
 
     // Check in body
     if (regex.test(prBody)) {
@@ -102,10 +109,7 @@ export function checkContainsTrigger(context: ParsedGitHubContext): boolean {
     (context.eventAction === "submitted" || context.eventAction === "edited")
   ) {
     const reviewBody = context.payload.review.body || "";
-    // Check for exact match with word boundaries or punctuation
-    const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
-    );
+    const regex = buildTriggerRegex(triggerPhrase);
     if (regex.test(reviewBody)) {
       console.log(
         `Pull request review contains exact trigger phrase '${triggerPhrase}'`,
@@ -122,10 +126,7 @@ export function checkContainsTrigger(context: ParsedGitHubContext): boolean {
     const commentBody = isIssueCommentEvent(context)
       ? context.payload.comment.body
       : context.payload.comment.body;
-    // Check for exact match with word boundaries or punctuation
-    const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
-    );
+    const regex = buildTriggerRegex(triggerPhrase);
     if (regex.test(commentBody)) {
       console.log(`Comment contains exact trigger phrase '${triggerPhrase}'`);
       return true;

test/trigger-validation.test.ts

@@ -184,8 +184,51 @@ describe("checkContainsTrigger", () => {
         { issueBody: "@claude: here's the issue", expected: true },
         { issueBody: "@claude; and another thing", expected: true },
         { issueBody: "Hey @claude, can you help?", expected: true },
+        { issueBody: "(@claude) can you check?", expected: true },
+        { issueBody: '"@claude can you check?"', expected: true },
+        { issueBody: ">@claude can you check?", expected: true },
+        { issueBody: "'@claude can you check?'", expected: true },
+        { issueBody: "/@claude can you check?", expected: true },
+        { issueBody: "cc:@claude check this", expected: true },
+        { issueBody: "`@claude` can you check?", expected: true },
+        { issueBody: "[@claude](https://example.com)", expected: true },
+        { issueBody: "**@claude** please help", expected: true },
+        { issueBody: "first line\n@claude help", expected: true },
         { issueBody: "claudette contains claude", expected: false },
         { issueBody: "email@claude.com", expected: false },
+        { issueBody: "user@claude.com", expected: false },
+        { issueBody: "@claude-bot helped me", expected: false },
+        { issueBody: "@claude-mention won't work", expected: false },
+      ];
+
+      testCases.forEach(({ issueBody, expected }) => {
+        const context = {
+          ...baseContext,
+          payload: {
+            ...baseContext.payload,
+            issue: {
+              ...(baseContext.payload as IssuesEvent).issue,
+              body: issueBody,
+            },
+          },
+        } as ParsedGitHubContext;
+        expect(checkContainsTrigger(context)).toBe(expected);
+      });
+    });
+
+    it("should match trigger phrase case-insensitively", () => {
+      const baseContext = {
+        ...mockIssueOpenedContext,
+        inputs: {
+          ...mockIssueOpenedContext.inputs,
+          triggerPhrase: "@claude",
+        },
+      };
+
+      const testCases = [
+        { issueBody: "@Claude help", expected: true },
+        { issueBody: "@CLAUDE help", expected: true },
+        { issueBody: "@cLaUdE help", expected: true },
       ];
 
       testCases.forEach(({ issueBody, expected }) => {
@@ -230,6 +273,10 @@ describe("checkContainsTrigger", () => {
         { issueTitle: "@claude, can you help?", expected: true },
         { issueTitle: "@claude: Fix this bug", expected: true },
         { issueTitle: "Bug: @claude please review", expected: true },
+        { issueTitle: "(@claude) Fix this bug", expected: true },
+        { issueTitle: "@Claude: Fix this bug", expected: true },
+        { issueTitle: "cc:@claude Fix this", expected: true },
+        { issueTitle: "`@claude` Fix this bug", expected: true },
         { issueTitle: "email@claude.com issue", expected: false },
         { issueTitle: "claudette needs help", expected: false },
       ];