Feat/BrowserOS-system-prompt

src/background/handlers/ProvidersHandler.ts

@@ -3,6 +3,7 @@ import { PortMessage } from '@/lib/runtime/PortMessaging'
 import { LLMSettingsReader } from '@/lib/llm/settings/LLMSettingsReader'
 import { langChainProvider } from '@/lib/llm/LangChainProvider'
 import { BrowserOSProvidersConfigSchema, BROWSEROS_PREFERENCE_KEYS } from '@/lib/llm/settings/browserOSTypes'
+import { clearCustomSystemPromptCache } from '@/lib/llm/settings/customSystemPrompt'
 import { Logging } from '@/lib/utils/Logging'
 import { PortManager } from '@/background/router/PortManager'
 
@@ -69,7 +70,8 @@ export class ProvidersHandler {
       if (payload.providers) {
         payload.providers = payload.providers.map((p: any) => ({
           ...p,
-          isDefault: p.isDefault !== undefined ? p.isDefault : (p.id === 'browseros')
+          isDefault: p.isDefault !== undefined ? p.isDefault : (p.id === 'browseros'),
+          systemPrompt: typeof p.systemPrompt === 'string' ? p.systemPrompt : ''
         }))
       }
       const config = BrowserOSProvidersConfigSchema.parse(payload)
@@ -116,6 +118,7 @@ export class ProvidersHandler {
       const success = browserOSSuccess || storageSuccess
       if (success) {
         try { langChainProvider.clearCache() } catch (_) {}
+        clearCustomSystemPromptCache()
         this.lastProvidersConfigJson = configStr
 
         this.broadcastProvidersConfig(config)

src/lib/agent/BrowserAgent.ts

@@ -13,6 +13,7 @@ import { Runnable } from "@langchain/core/runnables";
 import { BaseLanguageModelInput } from "@langchain/core/language_models/base";
 import { z } from "zod";
 import { getLLM } from "@/lib/llm/LangChainProvider";
+import { applyCustomSystemPrompt } from "@/lib/llm/settings/customSystemPrompt";
 import BrowserPage from "@/lib/browser/BrowserPage";
 import { PubSub } from "@/lib/pubsub";
 import { PubSubChannel } from "@/lib/pubsub/PubSubChannel";
@@ -733,7 +734,7 @@ export class BrowserAgent {
 
       // Get numbeer of tokens in full history
       // System prompt for planner
-      const systemPrompt = generatePlannerPrompt(this.toolDescriptions || "");
+      const systemPrompt = await applyCustomSystemPrompt(generatePlannerPrompt(this.toolDescriptions || ""));
 
       const systemPromptTokens = TokenCounter.countMessage(new SystemMessage(systemPrompt));
       const fullHistoryTokens = TokenCounter.countMessage(new HumanMessage(fullHistory));
@@ -842,7 +843,7 @@ ${fullHistory}
   ): Promise<ExecutorResult> {
     // Use the current iteration message manager from execution context
     const executorMM = new MessageManager();
-    const systemPrompt = generateExecutorPrompt(this._buildExecutionContext());
+    const systemPrompt = await applyCustomSystemPrompt(generateExecutorPrompt(this._buildExecutionContext()));
     const systemPromptTokens = TokenCounter.countMessage(new SystemMessage(systemPrompt));
     executorMM.addSystem(systemPrompt);
     const currentIterationToolMessages: string[] = [];
@@ -1359,7 +1360,7 @@ ${fullHistory}
       // Get accumulated execution history from all iterations
       let fullHistory = this._buildPlannerExecutionHistory();
 
-      const systemPrompt = generatePredefinedPlannerPrompt(this.toolDescriptions || "");
+      const systemPrompt = await applyCustomSystemPrompt(generatePredefinedPlannerPrompt(this.toolDescriptions || ""));
       const systemPromptTokens = TokenCounter.countMessage(new SystemMessage(systemPrompt));
       const fullHistoryTokens = TokenCounter.countMessage(new HumanMessage(fullHistory));
       Logging.log("BrowserAgent", `Full execution history tokens: ${fullHistoryTokens}`, "info");
@@ -1538,7 +1539,7 @@ ${fullHistory}
       intelligence: 'high'
     });
     const structuredLLM = llm.withStructuredOutput(ExecutionHistorySummarySchema);
-    const systemPrompt = generateExecutionHistorySummaryPrompt();
+    const systemPrompt = await applyCustomSystemPrompt(generateExecutionHistorySummaryPrompt());
     const userPrompt = `Execution History: ${historyWithoutSections}`;
     const messages = [
       new SystemMessage(systemPrompt),

src/lib/agent/LocalAgent.ts

@@ -13,6 +13,7 @@ import { Runnable } from "@langchain/core/runnables";
 import { BaseLanguageModelInput } from "@langchain/core/language_models/base";
 import { z } from "zod";
 import { getLLM } from "@/lib/llm/LangChainProvider";
+import { applyCustomSystemPrompt } from "@/lib/llm/settings/customSystemPrompt";
 import BrowserPage from "@/lib/browser/BrowserPage";
 import { PubSub } from "@/lib/pubsub";
 import { PubSubChannel } from "@/lib/pubsub/PubSubChannel";
@@ -691,7 +692,7 @@ export class LocalAgent {
 
       // Get numbeer of tokens in full history
       // System prompt for planner
-      const systemPrompt = generatePlannerPrompt(this.toolDescriptions || "");
+      const systemPrompt = await applyCustomSystemPrompt(generatePlannerPrompt(this.toolDescriptions || ""));
 
       const systemPromptTokens = TokenCounter.countMessage(new SystemMessage(systemPrompt));
       const fullHistoryTokens = TokenCounter.countMessage(new HumanMessage(fullHistory));
@@ -810,7 +811,7 @@ Continue upon the previous steps what has been done so far and suggest next step
   ): Promise<ExecutorResult> {
     // Use the current iteration message manager from execution context
     const executorMM = new MessageManager();
-    const systemPrompt = generateExecutorPrompt(this._buildExecutionContext());
+    const systemPrompt = await applyCustomSystemPrompt(generateExecutorPrompt(this._buildExecutionContext()));
     const systemPromptTokens = TokenCounter.countMessage(new SystemMessage(systemPrompt));
     executorMM.addSystem(systemPrompt);
     const currentIterationToolMessages: string[] = [];
@@ -1327,7 +1328,7 @@ Continue upon the previous steps what has been done so far and suggest next step
       // Get accumulated execution history from all iterations
       let fullHistory = this._buildPlannerExecutionHistory();
 
-      const systemPrompt = generatePredefinedPlannerPrompt(this.toolDescriptions || "");
+      const systemPrompt = await applyCustomSystemPrompt(generatePredefinedPlannerPrompt(this.toolDescriptions || ""));
       const systemPromptTokens = TokenCounter.countMessage(new SystemMessage(systemPrompt));
       const fullHistoryTokens = TokenCounter.countMessage(new HumanMessage(fullHistory));
       Logging.log("LocalAgent", `Full execution history tokens: ${fullHistoryTokens}`, "info");
@@ -1509,7 +1510,7 @@ Continue upon your previous steps what has been done so far and suggest next ste
       temperature: 0.2,
       maxTokens: 4096,
     });
-    const systemPrompt = generateExecutionHistorySummaryPrompt();
+    const systemPrompt = await applyCustomSystemPrompt(generateExecutionHistorySummaryPrompt());
     const userPrompt = `Execution History: ${historyWithoutSections}`;
     const messages = [
       new SystemMessage(systemPrompt),

src/lib/llm/settings/LLMSettingsReader.ts

@@ -9,6 +9,7 @@ import {
   createDefaultBrowserOSProvider,
   createDefaultProvidersConfig
 } from './browserOSTypes'
+import { setCachedDefaultProvider } from './customSystemPrompt'
 
 // Type definitions for chrome.browserOS API (callback-based)
 declare global {
@@ -57,6 +58,7 @@ export class LLMSettingsReader {
       ...provider,
       isDefault: provider.id === defaultProviderId,
       isBuiltIn: provider.isBuiltIn ?? false,
+      systemPrompt: typeof provider.systemPrompt === 'string' ? provider.systemPrompt : '',
       createdAt: provider.createdAt ?? new Date().toISOString(),
       updatedAt: provider.updatedAt ?? new Date().toISOString()
     }))
@@ -95,11 +97,14 @@ export class LLMSettingsReader {
       const provider = config.providers.find(p => p.id === config.defaultProviderId)
         || config.providers[0]
         || this.getDefaultBrowserOSProvider()
+      setCachedDefaultProvider(provider)
       return provider
     } catch (error) {
       const errorMessage = error instanceof Error ? error.message : String(error)
       Logging.log('LLMSettingsReader', `Failed to read settings: ${errorMessage}`, 'error')
-      return this.getDefaultBrowserOSProvider()
+      const fallback = this.getDefaultBrowserOSProvider()
+      setCachedDefaultProvider(fallback)
+      return fallback
     }
   }
 
@@ -110,14 +115,20 @@ export class LLMSettingsReader {
     try {
       const config = await this.readProvidersConfig()
       if (config) {
+        const defaultProvider = config.providers.find(p => p.id === config.defaultProviderId)
+          || config.providers[0]
+          || null
+        setCachedDefaultProvider(defaultProvider)
         return config
       }
     } catch (error) {
       const errorMessage = error instanceof Error ? error.message : String(error)
       Logging.log('LLMSettingsReader', `Failed to read providers: ${errorMessage}`, 'error')
     }
 
-    return createDefaultProvidersConfig()
+    const fallback = createDefaultProvidersConfig()
+    setCachedDefaultProvider(fallback.providers[0] || null)
+    return fallback
   }
 
   /**
@@ -300,6 +311,11 @@ export class LLMSettingsReader {
     const success = browserOSSuccess || storageSuccess
     if (!success) {
       Logging.log('LLMSettingsReader', 'Failed to save to any storage mechanism', 'error')
+    } else {
+      const defaultProvider = normalized.providers.find(p => p.id === normalized.defaultProviderId)
+        || normalized.providers[0]
+        || null
+      setCachedDefaultProvider(defaultProvider)
     }
     return success
   }

src/lib/llm/settings/browserOSTypes.ts

@@ -48,6 +48,7 @@ export const BrowserOSProviderSchema = z.object({
   baseUrl: z.string().optional(),  // API base URL
   apiKey: z.string().optional(),  // API key for authentication
   modelId: z.string().optional(),  // Model identifier
+  systemPrompt: z.string().optional(),  // Custom system prompt override
   capabilities: ProviderCapabilitiesSchema.optional(),  // Provider capabilities
   modelConfig: ModelConfigSchema.optional(),  // Model configuration
   createdAt: z.string(),  // ISO timestamp of creation
@@ -94,6 +95,7 @@ export function createDefaultBrowserOSProvider(): BrowserOSProvider {
     type: 'browseros',
     isDefault: true,
     isBuiltIn: true,
+    systemPrompt: '',
     createdAt: timestamp,
     updatedAt: timestamp
   }

src/lib/llm/settings/customSystemPrompt.ts

@@ -0,0 +1,59 @@
+import { BrowserOSProvider, BrowserOSProvidersConfig } from './browserOSTypes'
+import { LLMSettingsReader } from './LLMSettingsReader'
+
+let cachedProvider: BrowserOSProvider | null = null
+
+const cloneProvider = (provider: BrowserOSProvider | null): BrowserOSProvider | null => {
+  if (!provider) return null
+  return { ...provider }
+}
+
+const extractDefaultProvider = (config: BrowserOSProvidersConfig | null): BrowserOSProvider | null => {
+  if (!config) return null
+  const provider = config.providers.find(p => p.id === config.defaultProviderId) || config.providers[0] || null
+  return provider ? { ...provider } : null
+}
+
+const readDefaultProvider = async (): Promise<BrowserOSProvider | null> => {
+  try {
+    const config = await LLMSettingsReader.readAllProviders()
+    return extractDefaultProvider(config)
+  } catch (error) {
+    console.warn('[customSystemPrompt] Failed to read providers config:', error)
+    return null
+  }
+}
+
+export const clearCustomSystemPromptCache = (): void => {
+  cachedProvider = null
+}
+
+export const setCachedDefaultProvider = (provider: BrowserOSProvider | null): void => {
+  cachedProvider = cloneProvider(provider)
+}
+
+export const getCachedDefaultProvider = async (): Promise<BrowserOSProvider | null> => {
+  if (cachedProvider) {
+    return cachedProvider
+  }
+  const provider = await readDefaultProvider()
+  cachedProvider = cloneProvider(provider)
+  return cachedProvider
+}
+
+export const applyCustomSystemPrompt = async (basePrompt: string): Promise<string> => {
+  try {
+    const provider = await getCachedDefaultProvider()
+    if (!provider || provider.type !== 'browseros') {
+      return basePrompt
+    }
+    const customPrompt = (provider.systemPrompt ?? '').trim()
+    if (!customPrompt) {
+      return basePrompt
+    }
+    return `${customPrompt}\n\n${basePrompt}`
+  } catch (error) {
+    console.warn('[customSystemPrompt] Failed to apply custom prompt:', error)
+    return basePrompt
+  }
+}