app/agent/loop.ts
zzmq.dev@gmail.com/zz / app / agent / loop.ts
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- file This module implements a generic, tool‑calling loop that drives any `ChatBackend` (local Ollama, remote Gemini, etc.) by exchanging `ChatMessage`s, handling JSON‑string coercion, logging, partial‑response streaming, backend retry back‑off, and termination checks. It exports the `runAgent(opts: RunAgentOptions): Promise<RunAgentResult>` function together with the `RunAgentOptions` and `RunAgentResult` TypeScript interfaces that describe the caller’s configuration and the function’s outcome. No classes are exported.
+// A minimal local tool-calling loop against Ollama's /api/chat, which
+// genuinely supports OpenAI-style function-calling for tool-capable
+// models (verified directly against qwen2.5:14b-instruct before building
+// this). No Claude/Anthropic API, no BYOK -- local model only, per the
+// project's current scope.
+import type { ToolDef } from "./tools.js";
+interface ChatMessage {
+ role: "system" | "user" | "assistant" | "tool";
+ content: string;
+ tool_calls?: { function: { name: string; arguments: Record<string, unknown> } }[];
+}
+
+function toOllamaTools(tools: ToolDef[]) {
+ return tools.map((t) => ({ type: "function", function: { name: t.name, description: t.description, parameters: t.parameters } }));
+}
+
+function summarizeForLog(value: unknown): string {
+ const json = JSON.stringify(value);
+ if (!json) return String(value);
+ return json.length > 200 ? json.slice(0, 197) + "..." : json;
+}
+
+export interface RunAgentOptions {
+ systemPrompt: string;
+ userMessage: string;
+ tools: ToolDef[];
+ maxTurns?: number;
+ model?: string;
+ baseUrl?: string;
+}
+
+export interface RunAgentResult {
+ turns: number;
+ finished: boolean;
+ finalMessage: string;
+}
+
+export async function runAgent(opts: RunAgentOptions): Promise<RunAgentResult> {
+ const baseUrl = opts.baseUrl ?? process.env.ZZ_OLLAMA_HOST ?? "http://localhost:11434";
+ const model = opts.model ?? process.env.ZZ_OLLAMA_MODEL ?? "qwen2.5:14b-instruct";
+ const maxTurns = opts.maxTurns ?? 40;
+ const byName = new Map(opts.tools.map((t) => [t.name, t]));
+
+ const messages: ChatMessage[] = [
+ { role: "system", content: opts.systemPrompt },
+ { role: "user", content: opts.userMessage },
+ ];
+
+ for (let turn = 1; turn <= maxTurns; turn++) {
+ const res = await fetch(`${baseUrl}/api/chat`, {
+ method: "POST",
+ headers: { "content-type": "application/json" },
+ body: JSON.stringify({ model, messages, tools: toOllamaTools(opts.tools), stream: false }),
+ });
+ if (!res.ok) throw new Error(`ollama chat failed: ${res.status} ${await res.text()}`);
+ const data = (await res.json()) as { message: ChatMessage };
+ const { message } = data;
+ messages.push(message);
+
+ if (!message.tool_calls || message.tool_calls.length === 0) {
+ console.error(`[turn ${turn}] (no tool calls -- agent considers itself done)`);
+ return { turns: turn, finished: true, finalMessage: message.content };
+ }
+
+ for (const call of message.tool_calls) {
+ const tool = byName.get(call.function.name);
+ console.error(`[turn ${turn}] -> ${call.function.name}(${summarizeForLog(call.function.arguments)})`);
+ let result: unknown;
+ if (!tool) {
+ result = { error: `no such tool: ${call.function.name}` };
+ } else {
+ try {
+ result = await tool.execute(call.function.arguments);
+ } catch (err) {
+ result = { error: err instanceof Error ? err.message : String(err) };
+ }
+ }
+ console.error(` <- ${summarizeForLog(result)}`);
+ messages.push({ role: "tool", content: JSON.stringify(result) });
+ }
+ }
+
+ console.error(`stopped after ${maxTurns} turns without the agent finishing on its own.`);
+ return { turns: maxTurns, finished: false, finalMessage: "" };
+}
+