diff --git a/src/lock-ops.mjs b/src/lock-ops.mjs
index 9611779..e3fbcad 100644
--- a/src/lock-ops.mjs
+++ b/src/lock-ops.mjs
@@ -8,7 +8,7 @@ import {
   KIND_APP_DATA,
   MS_PER_SECOND,
 } from './constants.mjs';
-import { nowUnix, mergeRelayList } from './utils.mjs';
+import { nowUnix, relayListLabel } from './utils.mjs';
 import { defaultHealthManager, buildRelayHealthConfig, RelayHealthManager } from './relay-health-manager.mjs';
 import { publishLock, LockPublisher } from './lock-publisher.mjs';
 import {
@@ -61,6 +61,20 @@ function filterActiveLocks(locks) {
   return locks.filter((lock) => !lock.expiresAt || lock.expiresAt > now);
 }
 
+function withTimeout(promise, timeoutMs, timeoutMessage) {
+  let timeoutHandle;
+  const timeoutPromise = new Promise((_, reject) => {
+    timeoutHandle = setTimeout(() => reject(new Error(timeoutMessage)), timeoutMs);
+  });
+  return Promise.race([promise, timeoutPromise]).finally(() => {
+    if (timeoutHandle) clearTimeout(timeoutHandle);
+  });
+}
+
+function mergeRelayList(primaryRelays, fallbackRelays) {
+  return [...new Set([...primaryRelays, ...fallbackRelays])];
+}
+
 /**
  * Queries relays for active lock events matching the criteria.
  * Uses a tiered approach: tries primary relays first, then falls back to others if needed.
diff --git a/src/lock-publisher.mjs b/src/lock-publisher.mjs
index b7fa817..61fba13 100644
--- a/src/lock-publisher.mjs
+++ b/src/lock-publisher.mjs
@@ -8,17 +8,118 @@ import {
 } from './torch-config.mjs';
 import { mergeRelayList } from './utils.mjs';
 import { defaultHealthManager, buildRelayHealthConfig } from './relay-health-manager.mjs';
-import {
-  withTimeout,
-  relayListLabel,
-  mergeRelayList,
-  secureRandom,
-} from './lock-utils.mjs';
-import {
-  PUBLISH_FAILURE_CATEGORIES,
-  classifyPublishError,
-  isTransientPublishCategory,
-} from './lock-error-classifier.mjs';
+import { relayListLabel } from './utils.mjs';
+
+function withTimeout(promise, timeoutMs, timeoutMessage) {
+  let timeoutHandle;
+  const timeoutPromise = new Promise((_, reject) => {
+    timeoutHandle = setTimeout(() => reject(new Error(timeoutMessage)), timeoutMs);
+  });
+  return Promise.race([promise, timeoutPromise]).finally(() => {
+    if (timeoutHandle) clearTimeout(timeoutHandle);
+  });
+}
+
+function mergeRelayList(primaryRelays, fallbackRelays) {
+  return [...new Set([...primaryRelays, ...fallbackRelays])];
+}
+
+const PUBLISH_ERROR_CODES = {
+  TIMEOUT: 'publish_timeout',
+  DNS: 'dns_resolution',
+  TCP: 'tcp_connect_timeout',
+  TLS: 'tls_handshake',
+  WEBSOCKET: 'websocket_open_failure',
+  NETWORK: 'network_timeout',
+  CONNECTION_RESET: 'connection_reset',
+  RELAY_UNAVAILABLE: 'relay_unavailable',
+  PERMANENT: 'permanent_validation_error',
+};
+
+const PUBLISH_FAILURE_CATEGORIES = {
+  QUORUM_FAILURE: 'relay_publish_quorum_failure',
+  NON_RETRYABLE: 'relay_publish_non_retryable',
+};
+
+/**
+ * Classifies a raw error message into a standardized publication error code.
+ * Used to determine if a failure is transient (retryable) or permanent.
+ *
+ * @param {string|Error} message - The error message or object to classify.
+ * @returns {string} One of the PUBLISH_ERROR_CODES constants.
+ */
+function classifyPublishError(message) {
+  const normalized = String(message || '').toLowerCase();
+  if (normalized.includes('publish timed out after') || normalized.includes('publish timeout')) {
+    return PUBLISH_ERROR_CODES.TIMEOUT;
+  }
+  if (
+    normalized.includes('enotfound')
+    || normalized.includes('eai_again')
+    || normalized.includes('getaddrinfo')
+    || (normalized.includes('dns') && normalized.includes('websocket'))
+  ) {
+    return PUBLISH_ERROR_CODES.DNS;
+  }
+  if (
+    normalized.includes('connect etimedout')
+    || normalized.includes('tcp connect timed out')
+    || normalized.includes('connect timeout')
+  ) {
+    return PUBLISH_ERROR_CODES.TCP;
+  }
+  if (
+    normalized.includes('tls')
+    || normalized.includes('ssl')
+    || normalized.includes('certificate')
+    || normalized.includes('handshake')
+  ) {
+    return PUBLISH_ERROR_CODES.TLS;
+  }
+  if (
+    normalized.includes('websocket')
+    || normalized.includes('bad response')
+    || normalized.includes('unexpected server response')
+  ) {
+    return PUBLISH_ERROR_CODES.WEBSOCKET;
+  }
+  if (normalized.includes('timed out') || normalized.includes('timeout') || normalized.includes('etimedout')) {
+    return PUBLISH_ERROR_CODES.NETWORK;
+  }
+  if (normalized.includes('econnreset') || normalized.includes('connection reset') || normalized.includes('socket hang up')) {
+    return PUBLISH_ERROR_CODES.CONNECTION_RESET;
+  }
+  if (
+    normalized.includes('unavailable')
+    || normalized.includes('offline')
+    || normalized.includes('econnrefused')
+    || normalized.includes('connection refused')
+    || normalized.includes('enotfound')
+    || normalized.includes('503')
+  ) {
+    return PUBLISH_ERROR_CODES.RELAY_UNAVAILABLE;
+  }
+  return PUBLISH_ERROR_CODES.PERMANENT;
+}
+
+function isTransientPublishCategory(category) {
+  return [
+    PUBLISH_ERROR_CODES.TIMEOUT,
+    PUBLISH_ERROR_CODES.DNS,
+    PUBLISH_ERROR_CODES.TCP,
+    PUBLISH_ERROR_CODES.TLS,
+    PUBLISH_ERROR_CODES.WEBSOCKET,
+    PUBLISH_ERROR_CODES.NETWORK,
+    PUBLISH_ERROR_CODES.CONNECTION_RESET,
+    PUBLISH_ERROR_CODES.RELAY_UNAVAILABLE,
+  ].includes(category);
+}
+
+const MAX_RANDOM = 281474976710655; // 2**48 - 1
+
+export function secureRandom() {
+  return randomInt(0, MAX_RANDOM) / MAX_RANDOM;
+}
 
 function calculateBackoffDelayMs(attemptNumber, baseMs, capMs, randomFn = secureRandom) {
   const maxDelay = Math.min(capMs, baseMs * (2 ** Math.max(0, attemptNumber - 1)));
diff --git a/src/lock-utils.mjs b/src/lock-utils.mjs
index a064014..dbe1820 100644
--- a/src/lock-utils.mjs
+++ b/src/lock-utils.mjs
@@ -3,6 +3,8 @@ import path from 'node:path';
 import { randomInt } from 'node:crypto';
 import { todayDateStr, getIsoWeekStr } from './utils.mjs';
 
+export { relayListLabel } from './utils.mjs';
+
 /**
  * Scans the local log directory to identify agents that have already completed their task
  * for the current period (daily or weekly).
@@ -51,10 +53,6 @@ export async function getCompletedAgents(cadence, logDir, deps) {
 
 export { withTimeout };
 
-export function relayListLabel(relays) {
-  return relays.join(', ');
-}
-
 export function mergeRelayList(primaryRelays, fallbackRelays) {
   return [...new Set([...primaryRelays, ...fallbackRelays])];
 }
diff --git a/src/utils.mjs b/src/utils.mjs
index abd9f9d..4397000 100644
--- a/src/utils.mjs
+++ b/src/utils.mjs
@@ -52,12 +52,6 @@ export function ensureDir(dir) {
   }
 }
 
-export function withTimeout(promise, timeoutMs, timeoutMessage) {
-  let timeoutHandle;
-  const timeoutPromise = new Promise((_, reject) => {
-    timeoutHandle = setTimeout(() => reject(new Error(timeoutMessage)), timeoutMs);
-  });
-  return Promise.race([promise, timeoutPromise]).finally(() => {
-    if (timeoutHandle) clearTimeout(timeoutHandle);
-  });
+export function relayListLabel(relays) {
+  return relays.join(', ');
 }
diff --git a/test/utils.test.mjs b/test/utils.test.mjs
index 0c59f6a..7051687 100644
--- a/test/utils.test.mjs
+++ b/test/utils.test.mjs
@@ -2,7 +2,7 @@ import { describe, it, after } from 'node:test';
 import assert from 'node:assert';
 import fs from 'node:fs';
 import path from 'node:path';
-import { getIsoWeekStr, todayDateStr, nowUnix, ensureDir, detectPlatform, mergeRelayList } from '../src/utils.mjs';
+import { getIsoWeekStr, todayDateStr, nowUnix, ensureDir, detectPlatform, relayListLabel } from '../src/utils.mjs';
 
 describe('Date Utilities', () => {
   describe('todayDateStr', () => {
@@ -201,3 +201,22 @@ describe('File Utilities', () => {
     });
   });
 });
+
+describe('String Utilities', () => {
+  describe('relayListLabel', () => {
+    it('joins relay URLs with comma and space', () => {
+      const relays = ['ws://relay1.com', 'ws://relay2.com'];
+      assert.strictEqual(relayListLabel(relays), 'ws://relay1.com, ws://relay2.com');
+    });
+
+    it('handles single relay', () => {
+      const relays = ['ws://relay1.com'];
+      assert.strictEqual(relayListLabel(relays), 'ws://relay1.com');
+    });
+
+    it('handles empty array', () => {
+      const relays = [];
+      assert.strictEqual(relayListLabel(relays), '');
+    });
+  });
+});