From 5dea88db4c871e1e4f4c40be487f826b0ce5411e Mon Sep 17 00:00:00 2001
From: Maxwell Calkin <MaxwellCalkin@gmail.com>
Date: Sun, 8 Mar 2026 11:52:00 -0400
Subject: [PATCH] fix: allow trigger_phrase after punctuation, not just
 whitespace (#941)
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The trigger phrase regex used `(^|\s)` as the leading boundary, which
only matched after start-of-string or whitespace. This caused silent
failures when users wrote the trigger phrase after common punctuation
like parentheses, quotes, angle brackets, or colons — e.g. `(@claude)`,
`"@claude"`, `>@claude`, `cc:@claude`.

Replace `(^|\s)` with `(?<![a-zA-Z0-9_])` (negative lookbehind for
word characters). This allows matching after any non-word character
while still preventing false positives inside email addresses like
`user@claude.com` or partial word matches like `claudette`.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/github/validation/trigger.ts |  16 +--
 test/trigger-validation.test.ts  | 163 +++++++++++++++++++++++++++++++
 2 files changed, 171 insertions(+), 8 deletions(-)

diff --git a/src/github/validation/trigger.ts b/src/github/validation/trigger.ts
index 74b385d8d..1f7e6159b 100644
--- a/src/github/validation/trigger.ts
+++ b/src/github/validation/trigger.ts
@@ -48,9 +48,9 @@ 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
+    // Check for exact match - trigger phrase must not be preceded by a word character
     const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
+      `(?<![a-zA-Z0-9_])${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
     );
 
     // Check in body
@@ -74,9 +74,9 @@ 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
+    // Check for exact match - trigger phrase must not be preceded by a word character
     const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
+      `(?<![a-zA-Z0-9_])${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
     );
 
     // Check in body
@@ -102,9 +102,9 @@ 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
+    // Check for exact match - trigger phrase must not be preceded by a word character
     const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
+      `(?<![a-zA-Z0-9_])${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
     );
     if (regex.test(reviewBody)) {
       console.log(
@@ -122,9 +122,9 @@ 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
+    // Check for exact match - trigger phrase must not be preceded by a word character
     const regex = new RegExp(
-      `(^|\\s)${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
+      `(?<![a-zA-Z0-9_])${escapeRegExp(triggerPhrase)}([\\s.,!?;:]|$)`,
     );
     if (regex.test(commentBody)) {
       console.log(`Comment contains exact trigger phrase '${triggerPhrase}'`);
diff --git a/test/trigger-validation.test.ts b/test/trigger-validation.test.ts
index 36c41f287..51bac3bd6 100644
--- a/test/trigger-validation.test.ts
+++ b/test/trigger-validation.test.ts
@@ -467,3 +467,166 @@ describe("escapeRegExp", () => {
     expect(escapeRegExp("test[123]")).toBe("test\\[123\\]");
   });
 });
+
+describe("trigger phrase preceded by non-whitespace characters (#941)", () => {
+  describe("issue body - non-whitespace leading boundaries", () => {
+    const baseContext = {
+      ...mockIssueOpenedContext,
+      inputs: {
+        ...mockIssueOpenedContext.inputs,
+        triggerPhrase: "@claude",
+      },
+    };
+
+    function makeIssueContext(body: string): ParsedGitHubContext {
+      return {
+        ...baseContext,
+        payload: {
+          ...baseContext.payload,
+          issue: {
+            ...(baseContext.payload as IssuesEvent).issue,
+            body,
+          },
+        },
+      } as ParsedGitHubContext;
+    }
+
+    it("should trigger when preceded by parenthesis", () => {
+      expect(checkContainsTrigger(makeIssueContext("(@claude) can you check?"))).toBe(true);
+    });
+
+    it("should trigger when preceded by double quote", () => {
+      expect(checkContainsTrigger(makeIssueContext('"@claude can you check?"'))).toBe(true);
+    });
+
+    it("should trigger when preceded by single quote", () => {
+      expect(checkContainsTrigger(makeIssueContext("'@claude can you check?'"))).toBe(true);
+    });
+
+    it("should trigger when preceded by angle bracket (blockquote)", () => {
+      expect(checkContainsTrigger(makeIssueContext(">@claude can you check?"))).toBe(true);
+    });
+
+    it("should trigger when preceded by colon", () => {
+      expect(checkContainsTrigger(makeIssueContext("cc:@claude please review"))).toBe(true);
+    });
+
+    it("should trigger when preceded by backtick", () => {
+      expect(checkContainsTrigger(makeIssueContext("`@claude`"))).toBe(true);
+    });
+
+    it("should trigger when preceded by slash", () => {
+      expect(checkContainsTrigger(makeIssueContext("/@claude help"))).toBe(true);
+    });
+
+    it("should trigger when preceded by hyphen/dash", () => {
+      expect(checkContainsTrigger(makeIssueContext("-@claude fix it"))).toBe(true);
+    });
+
+    it("should still trigger at start of string", () => {
+      expect(checkContainsTrigger(makeIssueContext("@claude help me"))).toBe(true);
+    });
+
+    it("should still trigger after whitespace", () => {
+      expect(checkContainsTrigger(makeIssueContext("hey @claude help"))).toBe(true);
+    });
+
+    it("should still reject when preceded by word characters", () => {
+      expect(checkContainsTrigger(makeIssueContext("email@claude.com"))).toBe(false);
+    });
+
+    it("should still reject when trigger is part of a longer word", () => {
+      expect(checkContainsTrigger(makeIssueContext("claudette helped"))).toBe(false);
+    });
+
+    it("should reject when preceded by digits", () => {
+      expect(checkContainsTrigger(makeIssueContext("123@claude"))).toBe(false);
+    });
+
+    it("should reject when preceded by underscore", () => {
+      expect(checkContainsTrigger(makeIssueContext("_@claude"))).toBe(false);
+    });
+  });
+
+  describe("comment body - non-whitespace leading boundaries", () => {
+    const baseContext = {
+      ...mockIssueCommentContext,
+      inputs: {
+        ...mockIssueCommentContext.inputs,
+        triggerPhrase: "@claude",
+      },
+    };
+
+    function makeCommentContext(body: string): ParsedGitHubContext {
+      return {
+        ...baseContext,
+        payload: {
+          ...baseContext.payload,
+          comment: {
+            ...(baseContext.payload as IssueCommentEvent).comment,
+            body,
+          },
+        },
+      } as ParsedGitHubContext;
+    }
+
+    it("should trigger when preceded by parenthesis", () => {
+      expect(checkContainsTrigger(makeCommentContext("(@claude) can you check?"))).toBe(true);
+    });
+
+    it("should trigger when preceded by double quote", () => {
+      expect(checkContainsTrigger(makeCommentContext('"@claude help"'))).toBe(true);
+    });
+
+    it("should trigger when preceded by angle bracket", () => {
+      expect(checkContainsTrigger(makeCommentContext(">@claude review this"))).toBe(true);
+    });
+
+    it("should trigger when preceded by colon", () => {
+      expect(checkContainsTrigger(makeCommentContext("cc:@claude"))).toBe(true);
+    });
+
+    it("should still reject email-like patterns", () => {
+      expect(checkContainsTrigger(makeCommentContext("user@claude.com"))).toBe(false);
+    });
+  });
+
+  describe("PR review - non-whitespace leading boundaries", () => {
+    const baseContext = {
+      ...mockPullRequestReviewContext,
+      inputs: {
+        ...mockPullRequestReviewContext.inputs,
+        triggerPhrase: "@claude",
+      },
+    };
+
+    function makeReviewContext(body: string): ParsedGitHubContext {
+      return {
+        ...baseContext,
+        payload: {
+          ...baseContext.payload,
+          review: {
+            ...(baseContext.payload as PullRequestReviewEvent).review,
+            body,
+          },
+        },
+      } as ParsedGitHubContext;
+    }
+
+    it("should trigger when preceded by parenthesis", () => {
+      expect(checkContainsTrigger(makeReviewContext("(@claude) please review"))).toBe(true);
+    });
+
+    it("should trigger when preceded by double quote", () => {
+      expect(checkContainsTrigger(makeReviewContext('"@claude review"'))).toBe(true);
+    });
+
+    it("should trigger when preceded by single quote", () => {
+      expect(checkContainsTrigger(makeReviewContext("'@claude review'"))).toBe(true);
+    });
+
+    it("should still reject email-like patterns", () => {
+      expect(checkContainsTrigger(makeReviewContext("admin@claude.io"))).toBe(false);
+    });
+  });
+});