From 6dcc283d147efdfc2770c9c2f8f2db5568e85d90 Mon Sep 17 00:00:00 2001
From: Srujan Gurram <srujangs8@gmail.com>
Date: Mon, 6 Apr 2026 16:56:06 +0530
Subject: [PATCH] fix: improve default fingerprint aggregation to reduce alert
 noise

Normalize titles with the same rules used for messages so dynamic values
(UUIDs, hex addresses, numbers) don't create separate fingerprints.
Reduce default stackDepth from 3 to 1 so the same error originating from
one throw site but reached via different callers groups into a single
aggregation stream.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .changeset/fingerprint-aggregation.md |  8 ++++++++
 src/core/fingerprinter.test.ts        | 27 ++++++++++++++++++++++++++-
 src/core/fingerprinter.ts             |  3 ++-
 src/core/types.ts                     |  2 +-
 4 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/fingerprint-aggregation.md

diff --git a/.changeset/fingerprint-aggregation.md b/.changeset/fingerprint-aggregation.md
new file mode 100644
index 0000000..69e9c17
--- /dev/null
+++ b/.changeset/fingerprint-aggregation.md
@@ -0,0 +1,8 @@
+---
+"@iqai/alert-logger": patch
+---
+
+fix: improve default fingerprint aggregation to reduce alert noise
+
+- Normalize titles with the same rules used for messages (UUIDs, hex addresses, timestamps, numbers) so dynamic values in titles don't split fingerprints.
+- Reduce default `stackDepth` from 3 to 1 so the same error from different callers groups into a single aggregation stream. Users can restore the previous behavior with `fingerprint: { stackDepth: 3 }`.
diff --git a/src/core/fingerprinter.test.ts b/src/core/fingerprinter.test.ts
index a8266ec..688bb85 100644
--- a/src/core/fingerprinter.test.ts
+++ b/src/core/fingerprinter.test.ts
@@ -187,6 +187,25 @@ describe('fingerprint', () => {
       expect(a).not.toBe(b)
     })
 
+    it('groups same error from different callers with default stackDepth', () => {
+      const stackA = [
+        'Error: test',
+        '    at throwSite (/app/src/shared.ts:10:5)',
+        '    at callerA (/app/src/a.ts:20:3)',
+        '    at handlerA (/app/src/routes-a.ts:30:1)',
+      ].join('\n')
+      const stackB = [
+        'Error: test',
+        '    at throwSite (/app/src/shared.ts:10:5)',
+        '    at callerB (/app/src/b.ts:40:3)',
+        '    at handlerB (/app/src/routes-b.ts:50:1)',
+      ].join('\n')
+
+      const a = fingerprint('E', 'test', makeErrorWithStack(stackA), cfg)
+      const b = fingerprint('E', 'test', makeErrorWithStack(stackB), cfg)
+      expect(a).toBe(b)
+    })
+
     it('includes file, line, and column in stack key', () => {
       const stackA = ['Error: test', '    at fn (/app/src/index.ts:10:5)'].join('\n')
       const stackB = ['Error: test', '    at fn (/app/src/index.ts:10:99)'].join('\n')
@@ -205,10 +224,16 @@ describe('fingerprint', () => {
       expect(hash).toMatch(/^[0-9a-f]{32}$/)
     })
 
-    it('uses title as errorName when error is undefined', () => {
+    it('uses normalized title as errorName when error is undefined', () => {
       const a = fingerprint('TitleA', 'same msg', undefined, cfg)
       const b = fingerprint('TitleB', 'same msg', undefined, cfg)
       expect(a).not.toBe(b)
     })
+
+    it('normalizes dynamic parts in title when error is undefined', () => {
+      const a = fingerprint('GET /users/0xABC123DEF/positions', 'table missing', undefined, cfg)
+      const b = fingerprint('GET /users/0xDEF456ABC/positions', 'table missing', undefined, cfg)
+      expect(a).toBe(b)
+    })
   })
 })
diff --git a/src/core/fingerprinter.ts b/src/core/fingerprinter.ts
index aec4bf1..b90a100 100644
--- a/src/core/fingerprinter.ts
+++ b/src/core/fingerprinter.ts
@@ -69,9 +69,10 @@ export function fingerprint(
     return md5(dedupKey)
   }
 
+  const normalizedTitle = normalizeMessage(title, config.normalizers)
   const normalizedMessage = normalizeMessage(message, config.normalizers)
   const stackKey = extractStackKey(error, config.stackDepth)
-  const errorName = error?.name ?? title
+  const errorName = error?.name ?? normalizedTitle
 
   return md5(errorName + normalizedMessage + stackKey)
 }
diff --git a/src/core/types.ts b/src/core/types.ts
index a0df041..b3fceeb 100644
--- a/src/core/types.ts
+++ b/src/core/types.ts
@@ -139,7 +139,7 @@ export const DEFAULT_QUEUE: QueueConfig = {
 }
 
 export const DEFAULT_FINGERPRINT: FingerprintConfig = {
-  stackDepth: 3,
+  stackDepth: 1,
   normalizers: [],
 }