perf(pi): reuse tau rpc for command auto-replies

src/agents/gemini.ts

@@ -0,0 +1,50 @@
+import path from "node:path";
+
+import type { AgentMeta, AgentSpec } from "./types.js";
+
+const GEMINI_BIN = "gemini";
+export const GEMINI_IDENTITY_PREFIX =
+  "You are Gemini responding for warelay. Keep WhatsApp replies concise (<1500 chars). If the prompt contains media paths or a Transcript block, use them. If this was a heartbeat probe and nothing needs attention, reply with exactly HEARTBEAT_OK.";
+
+// Gemini CLI currently prints plain text; --output json is flaky across versions, so we
+// keep parsing minimal and let MEDIA token stripping happen later in the pipeline.
+function parseGeminiOutput(raw: string): { text?: string; meta?: AgentMeta } {
+  const trimmed = raw.trim();
+  return { text: trimmed || undefined, meta: undefined };
+}
+
+export const geminiSpec: AgentSpec = {
+  kind: "gemini",
+  isInvocation: (argv) =>
+    argv.length > 0 && path.basename(argv[0]) === GEMINI_BIN,
+  buildArgs: (ctx) => {
+    const argv = [...ctx.argv];
+    const body = argv[ctx.bodyIndex] ?? "";
+    const beforeBody = argv.slice(0, ctx.bodyIndex);
+    const afterBody = argv.slice(ctx.bodyIndex + 1);
+
+    if (ctx.format) {
+      const hasOutput =
+        beforeBody.some(
+          (p) => p === "--output-format" || p.startsWith("--output-format="),
+        ) ||
+        afterBody.some(
+          (p) => p === "--output-format" || p.startsWith("--output-format="),
+        );
+      if (!hasOutput) {
+        beforeBody.push("--output-format", ctx.format);
+      }
+    }
+
+    const shouldPrependIdentity = !(ctx.sendSystemOnce && ctx.systemSent);
+    const bodyWithIdentity =
+      shouldPrependIdentity && body
+        ? [ctx.identityPrefix ?? GEMINI_IDENTITY_PREFIX, body]
+            .filter(Boolean)
+            .join("\n\n")
+        : body;
+
+    return [...beforeBody, bodyWithIdentity, ...afterBody];
+  },
+  parseOutput: parseGeminiOutput,
+};