feat(pi-web-search): 统一 web_search/web_fetch 并由主模型路由搜索厂商

7 个按厂商命名的搜索工具收敛为 2 个统一工具，schema 与提示词不再暴露
provider 概念：web_search 由当前主模型按内置规则在 Tavily/Exa/Keenable
间路由（会话内 LRU 缓存，失败按可用性降级），web_fetch 固定走 Exa 并
静默降级。三家均改为纯 fetch 直连——Exa 直接对 mcp.exa.ai 发 JSON-RPC
并缓存会话，彻底移除 pi-mcp-adapter、@tavily/pi-extension 与
@keenable/pi-search 依赖。

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

extensions/exa-tool-prefix.ts

@@ -1,57 +0,0 @@
-const EXA_TOOL_ALIASES: Record<string, string> = {
-	web_search_exa: "exa_web_search",
-	web_fetch_exa: "exa_web_fetch",
-	web_search_advanced_exa: "exa_web_search_advanced",
-};
-
-export type ExaToolDefinition = {
-	name: string;
-	label: string;
-	[key: string]: unknown;
-};
-
-export function mapExaToolName(name: string): string {
-	return EXA_TOOL_ALIASES[name] ?? name;
-}
-
-export function prefixExaTool<T extends ExaToolDefinition>(definition: T): T {
-	const name = mapExaToolName(definition.name);
-	if (name === definition.name) return definition;
-
-	const displayName = name
-		.slice("exa_".length)
-		.split("_")
-		.map((part) => part.charAt(0).toUpperCase() + part.slice(1))
-		.join(" ");
-	return {
-		...definition,
-		name,
-		label: `Exa ${displayName}`,
-	} as T;
-}
-
-type ToolApi = {
-	registerTool: (tool: unknown) => unknown;
-	setActiveTools: (names: string[]) => unknown;
-	unregisterTool?: (name: string) => boolean;
-};
-
-export function createExaToolApiOverride<T extends object>(pi: T): T {
-	const api = pi as T & ToolApi;
-	return new Proxy(pi, {
-		get(target, property) {
-			if (property === "registerTool") {
-				return (definition: ExaToolDefinition) => api.registerTool(prefixExaTool(definition));
-			}
-			if (property === "setActiveTools") {
-				return (names: string[]) => api.setActiveTools([...new Set(names.map(mapExaToolName))]);
-			}
-			if (property === "unregisterTool") {
-				return api.unregisterTool ? (name: string) => api.unregisterTool?.(mapExaToolName(name)) : undefined;
-			}
-
-			const value = Reflect.get(target, property, target);
-			return typeof value === "function" ? value.bind(target) : value;
-		},
-	}) as T;
-}

extensions/mcp-config.ts

@@ -1,26 +0,0 @@
-
-export const EXA_TOOLS = ["web_search_exa", "web_fetch_exa", "web_search_advanced_exa"];
-const EXA_MCP_URL = `https://mcp.exa.ai/mcp?tools=${EXA_TOOLS.join(",")}`;
-
-export function createMcpConfig(env: Record<string, string | undefined>) {
-	const hasExaApiKey = Boolean(env.EXA_API_KEY?.trim());
-	return {
-		settings: {
-			disableProxyTool: true,
-			scriptMode: false,
-		},
-		mcpServers: {
-			exa: {
-				url: EXA_MCP_URL,
-				...(hasExaApiKey ? { headers: { "x-api-key": "$env:EXA_API_KEY" } } : {}),
-				protocolVersion: "auto" as const,
-				lifecycle: "eager" as const,
-				directTools: EXA_TOOLS,
-				includeTools: EXA_TOOLS,
-				toolPrefix: "none" as const,
-				approveTools: false,
-				exposeResources: false,
-			},
-		},
-	};
-}

extensions/mcp.ts

@@ -1,12 +0,0 @@
-import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
-import { createMcpAdapter } from "pi-mcp-adapter";
-import { createExaToolApiOverride } from "./exa-tool-prefix.ts";
-import { createMcpConfig } from "./mcp-config.ts";
-import { loadSearchConfigEnv } from "./search-config.ts";
-
-/** Connect Pi to Exa's hosted MCP through the shared adapter instance. CodeGraph is a native tool (see codegraph.ts), not an MCP server. */
-export default function mcpExtension(pi: ExtensionAPI): void {
-	const searchEnvironment = loadSearchConfigEnv();
-	const mcpAdapter = createMcpAdapter({ config: createMcpConfig(searchEnvironment) });
-	mcpAdapter(createExaToolApiOverride(pi));
-}

extensions/tavily-override.ts

@@ -1,21 +0,0 @@
-import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
-import tavilyExtension from "../node_modules/@tavily/pi-extension/index.ts";
-import { prefixTavilyTool, type TavilyToolDefinition } from "./tavily-tool-prefix.ts";
-
-
-/** Load Tavily while making the provider explicit in every registered tool name. */
-export default function tavilyOverrideExtension(pi: ExtensionAPI): void {
-	const prefixedPi = new Proxy(pi, {
-		get(target, property) {
-			if (property === "registerTool") {
-				return (definition: TavilyToolDefinition) =>
-					(target.registerTool as (tool: unknown) => void)(prefixTavilyTool(definition));
-			}
-
-			const value = Reflect.get(target, property, target);
-			return typeof value === "function" ? value.bind(target) : value;
-		},
-	});
-
-	tavilyExtension(prefixedPi);
-}

extensions/tavily-tool-prefix.ts

@@ -1,25 +0,0 @@
-const TAVILY_TOOL_PREFIX = "tavily_";
-
-export type TavilyToolDefinition = {
-	name: string;
-	label: string;
-	description: string;
-	promptSnippet?: string;
-	promptGuidelines?: string[];
-	[key: string]: unknown;
-};
-
-function rewriteToolReferences(text: string): string {
-	return text.replace(/\bweb_search\b/g, "tavily_web_search").replace(/\bweb_fetch\b/g, "tavily_web_fetch");
-}
-
-export function prefixTavilyTool<T extends TavilyToolDefinition>(definition: T): T {
-	return {
-		...definition,
-		name: `${TAVILY_TOOL_PREFIX}${definition.name}`,
-		label: definition.label.startsWith("Tavily ") ? definition.label : `Tavily ${definition.label}`,
-		description: rewriteToolReferences(definition.description),
-		promptSnippet: definition.promptSnippet ? rewriteToolReferences(definition.promptSnippet) : undefined,
-		promptGuidelines: definition.promptGuidelines?.map(rewriteToolReferences),
-	} as T;
-}

extensions/tool-routing.ts

@@ -62,27 +62,9 @@ export function buildToolRoutingSection(selectedTools: SelectedTools): string {
 		);
 	}
 
-	const tavilyTools = ["tavily_web_search", "tavily_web_fetch"];
-	const exaTools = ["exa_web_search", "exa_web_fetch", "exa_web_search_advanced"];
-	const keenableTools = ["keenable_search", "keenable_fetch"];
-	if (hasAnyTool(selectedTools, [...tavilyTools, ...exaTools, ...keenableTools])) {
+	if (hasAnyTool(selectedTools, ["web_search", "web_fetch"])) {
 		rules.push(
-			"- Choose one online search provider based on the task instead of querying Tavily, Exa, and Keenable by default; cross-check with another provider only when source quality or uncertainty warrants it.",
-		);
-	}
-	if (hasAnyTool(selectedTools, tavilyTools)) {
-		rules.push(
-			"- Use Tavily tools for broad discovery when keywords are uncertain, for news/recent/trending topics, or when many candidate sources are useful. Tavily results can mix official pages, blogs, forums, and secondary sources, so keep max_results modest, avoid raw content unless needed, and fetch only selected pages when depth matters.",
-		);
-	}
-	if (hasAnyTool(selectedTools, exaTools)) {
-		rules.push(
-			"- Use Exa tools when source precision matters: official or API documentation, release/version information, academic papers, research material, and high-quality fact confirmation. Use exa_web_fetch to continue reading selected pages; for exa_web_search_advanced, explicitly bound the result count and returned text length to prevent oversized responses.",
-		);
-	}
-	if (hasAnyTool(selectedTools, keenableTools)) {
-		rules.push(
-			"- Use Keenable tools for Chinese-language pages, policies and government notices, site-restricted search, and publication-date filtering. Prefer its compact search results and fetch only selected pages to keep returned content controlled; KEENABLE_API_KEY is optional but raises rate limits.",
+			"- Use web_search for current, real-world, or citable web information; provider selection is handled internally. Keep queries focused and use site/published_* filters only when they materially narrow results. Then read selected pages with web_fetch instead of repeating similar searches.",
 		);
 	}