Enhance error handling and validation in agents and routes

- Added logging for empty responses in GeminiAgent and OpenRouterAgent to track potential session context issues.
- Refactored settings file path usage in OpenRouterAgent to use a constant for better maintainability.
- Improved error handling in SessionRoutes to log generator failures with detailed context.
- Implemented JSON parsing error handling in SettingsRoutes to manage corrupted settings files gracefully.
- Added validation for CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES, CLAUDE_MEM_OPENROUTER_MAX_TOKENS, and CLAUDE_MEM_OPENROUTER_SITE_URL in SettingsRoutes to ensure valid configuration.

src/services/worker/GeminiAgent.ts

@@ -170,6 +170,11 @@ export class GeminiAgent {
 
         // Process response (no original timestamp for init - not from queue)
         await this.processGeminiResponse(session, initResponse.content, worker, tokensUsed, null);
+      } else {
+        logger.warn('SDK', 'Empty Gemini init response - session may lack context', {
+          sessionId: session.sessionDbId,
+          model
+        });
       }
 
       // Process pending messages

src/services/worker/OpenRouterAgent.ts

@@ -11,14 +11,13 @@
  * - Support dynamic model selection across providers
  */
 
-import path from 'path';
-import { homedir } from 'os';
 import { DatabaseManager } from './DatabaseManager.js';
 import { SessionManager } from './SessionManager.js';
 import { logger } from '../../utils/logger.js';
 import { parseObservations, parseSummary } from '../../sdk/parser.js';
 import { buildInitPrompt, buildObservationPrompt, buildSummaryPrompt, buildContinuationPrompt } from '../../sdk/prompts.js';
 import { SettingsDefaultsManager } from '../../shared/SettingsDefaultsManager.js';
+import { USER_SETTINGS_PATH } from '../../shared/paths.js';
 import type { ActiveSession, ConversationMessage } from '../worker-types.js';
 import { ModeManager } from '../domain/ModeManager.js';
 
@@ -131,6 +130,11 @@ export class OpenRouterAgent {
 
         // Process response (no original timestamp for init - not from queue)
         await this.processOpenRouterResponse(session, initResponse.content, worker, tokensUsed, null);
+      } else {
+        logger.warn('SDK', 'Empty OpenRouter init response - session may lack context', {
+          sessionId: session.sessionDbId,
+          model
+        });
       }
 
       // Process pending messages
@@ -263,7 +267,7 @@ export class OpenRouterAgent {
    */
   private truncateHistory(history: ConversationMessage[]): ConversationMessage[] {
     const settings = SettingsDefaultsManager.loadFromFile(
-      path.join(homedir(), '.claude-mem', 'settings.json')
+      USER_SETTINGS_PATH
     );
 
     const MAX_CONTEXT_MESSAGES = parseInt(settings.CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES) || DEFAULT_MAX_CONTEXT_MESSAGES;
@@ -377,7 +381,7 @@ export class OpenRouterAgent {
     if (tokensUsed) {
       const inputTokens = data.usage?.prompt_tokens || 0;
       const outputTokens = data.usage?.completion_tokens || 0;
-      // Rough cost estimate (Claude 3.5 Sonnet pricing: $3/MTok input, $15/MTok output)
+      // Token usage (cost varies by model - many OpenRouter models are free)
       const estimatedCost = (inputTokens / 1000000 * 3) + (outputTokens / 1000000 * 15);
 
       logger.info('SDK', 'OpenRouter API usage', {
@@ -568,7 +572,7 @@ export class OpenRouterAgent {
    * Get OpenRouter configuration from settings or environment
    */
   private getOpenRouterConfig(): { apiKey: string; model: string; siteUrl?: string; appName?: string } {
-    const settingsPath = path.join(homedir(), '.claude-mem', 'settings.json');
+    const settingsPath = USER_SETTINGS_PATH;
     const settings = SettingsDefaultsManager.loadFromFile(settingsPath);
 
     // API key: check settings first, then environment variable
@@ -589,7 +593,7 @@ export class OpenRouterAgent {
  * Check if OpenRouter is available (has API key configured)
  */
 export function isOpenRouterAvailable(): boolean {
-  const settingsPath = path.join(homedir(), '.claude-mem', 'settings.json');
+  const settingsPath = USER_SETTINGS_PATH;
   const settings = SettingsDefaultsManager.loadFromFile(settingsPath);
   return !!(settings.CLAUDE_MEM_OPENROUTER_API_KEY || process.env.OPENROUTER_API_KEY);
 }
@@ -598,7 +602,7 @@ export function isOpenRouterAvailable(): boolean {
  * Check if OpenRouter is the selected provider
  */
 export function isOpenRouterSelected(): boolean {
-  const settingsPath = path.join(homedir(), '.claude-mem', 'settings.json');
+  const settingsPath = USER_SETTINGS_PATH;
   const settings = SettingsDefaultsManager.loadFromFile(settingsPath);
   return settings.CLAUDE_MEM_PROVIDER === 'openrouter';
 }

src/services/worker/http/routes/SessionRoutes.ts

@@ -135,6 +135,13 @@ export class SessionRoutes extends BaseRouteHandler {
     session.currentProvider = provider;
 
     session.generatorPromise = agent.startSession(session, this.workerService)
+      .catch(error => {
+        logger.error('SESSION', `Generator failed`, {
+          sessionId: session.sessionDbId,
+          provider: provider,
+          error: error.message
+        }, error);
+      })
       .finally(() => {
         logger.info('SESSION', `Generator finished`, { sessionId: session.sessionDbId });
         session.generatorPromise = null;

src/services/worker/http/routes/SettingsRoutes.ts

@@ -71,7 +71,16 @@ export class SettingsRoutes extends BaseRouteHandler {
 
     if (existsSync(settingsPath)) {
       const settingsData = readFileSync(settingsPath, 'utf-8');
-      settings = JSON.parse(settingsData);
+      try {
+        settings = JSON.parse(settingsData);
+      } catch (parseError) {
+        logger.error('SETTINGS', 'Failed to parse settings file', { settingsPath }, parseError as Error);
+        res.status(500).json({
+          success: false,
+          error: 'Settings file is corrupted. Delete ~/.claude-mem/settings.json to reset.'
+        });
+        return;
+      }
     }
 
     // Update all settings from request body
@@ -319,6 +328,31 @@ export class SettingsRoutes extends BaseRouteHandler {
       }
     }
 
+    // Validate CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES
+    if (settings.CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES) {
+      const count = parseInt(settings.CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES, 10);
+      if (isNaN(count) || count < 1 || count > 100) {
+        return { valid: false, error: 'CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES must be between 1 and 100' };
+      }
+    }
+
+    // Validate CLAUDE_MEM_OPENROUTER_MAX_TOKENS
+    if (settings.CLAUDE_MEM_OPENROUTER_MAX_TOKENS) {
+      const tokens = parseInt(settings.CLAUDE_MEM_OPENROUTER_MAX_TOKENS, 10);
+      if (isNaN(tokens) || tokens < 1000 || tokens > 1000000) {
+        return { valid: false, error: 'CLAUDE_MEM_OPENROUTER_MAX_TOKENS must be between 1000 and 1000000' };
+      }
+    }
+
+    // Validate CLAUDE_MEM_OPENROUTER_SITE_URL if provided
+    if (settings.CLAUDE_MEM_OPENROUTER_SITE_URL) {
+      try {
+        new URL(settings.CLAUDE_MEM_OPENROUTER_SITE_URL);
+      } catch {
+        return { valid: false, error: 'CLAUDE_MEM_OPENROUTER_SITE_URL must be a valid URL' };
+      }
+    }
+
     // Skip observation types validation - any type string is valid since modes define their own types
     // The database accepts any TEXT value, and mode-specific validation happens at parse time