feat: deepseek agent adapter for pipeline — Ollama-based model runtime

runDeepSeekAgent() implements the runAgent callback for execution-pipeline.ts.
Configurable endpoint/model/temperature. Uses fetch (Node 18+), no new deps.
Exports from index.ts.

src/fable5/deepseek-agent.ts

@@ -0,0 +1,92 @@
+/**
+ * Agent adapter for DeepSeek models via Ollama.
+ * Uses fetch (Node 18+ built-in, no new deps).
+ * Designed as the runAgent callback for execution-pipeline.ts.
+ *
+ * Configurable endpoint — defaults to localhost:11434.
+ * Point at 77.42.112.29:11434 when Ollama is reachable externally.
+ */
+
+export interface DeepSeekAgentConfig {
+  /** Ollama endpoint, e.g. "http://localhost:11434" */
+  endpoint?: string;
+  /** Model name, e.g. "deepseek-coder-v2" or "deepseek-r1:32b" */
+  model?: string;
+  /** Sampling temperature. Default 0.2 for coding tasks. */
+  temperature?: number;
+  /** System prompt injected before the user prompt. */
+  systemPrompt?: string;
+  /** Max tokens to generate. Default 4096. */
+  maxTokens?: number;
+}
+
+const DEFAULTS = {
+  endpoint: "http://localhost:11434",
+  model: "deepseek-coder-v2",
+  temperature: 0.2,
+  systemPrompt: "You are a coding agent. Read the repo map and user prompt, then produce the required output.",
+  maxTokens: 4096,
+};
+
+export interface ChatMessage {
+  role: "system" | "user" | "assistant";
+  content: string;
+}
+
+export function buildDeepSeekMessages(
+  systemPrompt: string,
+  prompt: string
+): ChatMessage[] {
+  return [
+    { role: "system", content: systemPrompt },
+    { role: "user", content: prompt },
+  ];
+}
+
+/**
+ * Run a DeepSeek model via Ollama's /api/chat endpoint.
+ * Returns the assistant's response text.
+ * Throws on HTTP error or empty response.
+ */
+export async function runDeepSeekAgent(
+  config: DeepSeekAgentConfig,
+  _cwd: string,
+  prompt: string
+): Promise<string> {
+  const endpoint = config.endpoint ?? DEFAULTS.endpoint;
+  const model = config.model ?? DEFAULTS.model;
+  const temperature = config.temperature ?? DEFAULTS.temperature;
+  const systemPrompt = config.systemPrompt ?? DEFAULTS.systemPrompt;
+  const maxTokens = config.maxTokens ?? DEFAULTS.maxTokens;
+
+  const messages = buildDeepSeekMessages(systemPrompt, prompt);
+
+  const response = await fetch(`${endpoint}/api/chat`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({
+      model,
+      messages,
+      options: {
+        temperature,
+        num_predict: maxTokens,
+      },
+      stream: false,
+    }),
+    signal: AbortSignal.timeout(120_000), // 2-minute timeout
+  });
+
+  if (!response.ok) {
+    const body = await response.text().catch(() => "");
+    throw new Error(`deepseek-agent: HTTP ${response.status} — ${body.slice(0, 200)}`);
+  }
+
+  const data: any = await response.json();
+  const text = data?.message?.content ?? "";
+
+  if (!text) {
+    throw new Error("deepseek-agent: empty response from model");
+  }
+
+  return text;
+}

src/fable5/index.ts

@@ -55,6 +55,8 @@ export { buildRepoMap, repoTreeString, minifiedTree, gitLsTree } from "./repo-ma
 export type { RepoMap, RepoNode } from "./repo-mapper.js";
 export { runPipeline } from "./execution-pipeline.js";
 export type { PipelineSpec, PipelineResult } from "./execution-pipeline.js";
+export { runDeepSeekAgent, buildDeepSeekMessages } from "./deepseek-agent.js";
+export type { DeepSeekAgentConfig, ChatMessage } from "./deepseek-agent.js";
 export { formatCapabilityReport, loadFactoryCapabilities, parseFactoryCapabilities, probeFactoryCapabilities } from "./factory-capabilities.js";
 export type { CapabilityProbeResult, CapabilityReport, FactoryCapabilityService } from "./factory-capabilities.js";