Restore preset-owned prompt/tool artifacts in wrapper path: add systemPromptPath artifact, write system-prompt.md, pass --tools and --append-system-prompt flags when present, preserve meta fields, and update tests

src/artifacts.test.ts

@@ -17,6 +17,8 @@ test("createRunArtifacts writes metadata and reserves stable artifact paths", as
   assert.match(artifacts.dir, /\.pi\/subagents\/runs\/run-1$/);
   const meta = JSON.parse(await readFile(artifacts.metaPath, "utf8"));
   assert.equal(meta.task, "inspect auth");
-  assert.equal("systemPromptPath" in meta, false);
+  // systemPromptPath should be present and point to the system-prompt.md file we created.
-  await assert.rejects(readFile(join(artifacts.dir, "system-prompt.md"), "utf8"));
+  assert.equal(typeof meta.systemPromptPath, "string");
+  const promptText = await readFile(join(artifacts.dir, "system-prompt.md"), "utf8");
+  assert.equal(promptText, "");
 });

src/artifacts.ts

@@ -12,6 +12,7 @@ export interface RunArtifacts {
   stderrPath: string;
   transcriptPath: string;
   sessionPath: string;
+  systemPromptPath: string;
 }
 
 export async function createRunArtifacts(
@@ -32,8 +33,14 @@ export async function createRunArtifacts(
     stderrPath: join(dir, "stderr.log"),
     transcriptPath: join(dir, "transcript.log"),
     sessionPath: join(dir, "child-session.jsonl"),
+    systemPromptPath: join(dir, "system-prompt.md"),
   };
 
+  // Write the system prompt file. If meta.systemPrompt is missing, write an empty string
+  // to keep the path stable for downstream consumers.
+  const systemPromptContent = typeof meta.systemPrompt === "string" ? meta.systemPrompt : "";
+  await writeFile(artifacts.systemPromptPath, systemPromptContent, "utf8");
+
   await writeFile(
     artifacts.metaPath,
     JSON.stringify(
@@ -46,6 +53,7 @@ export async function createRunArtifacts(
         stdoutPath: artifacts.stdoutPath,
         stderrPath: artifacts.stderrPath,
         transcriptPath: artifacts.transcriptPath,
+        systemPromptPath: artifacts.systemPromptPath,
       },
       null,
       2,

src/wrapper/cli.mjs

@@ -67,6 +67,28 @@ async function runWrapper(meta, startedAt) {
 
   const args = ["--mode", "json", "--session", meta.sessionPath];
   if (effectiveModel) args.push("--model", effectiveModel);
+
+  // Pass preset-owned tool list to the child pi process when available.
+  if (Array.isArray(meta.tools) && meta.tools.length > 0) {
+    try {
+      const csv = meta.tools.join(",");
+      args.push("--tools", csv);
+    } catch {
+      // ignore malformed tools metadata
+    }
+  }
+
+  // If a system prompt artifact path is present and the file exists, pass it along.
+  if (typeof meta.systemPromptPath === "string" && meta.systemPromptPath.length > 0) {
+    try {
+      // Verify file exists/readable. Do not fail if it's stale/missing.
+      await readFile(meta.systemPromptPath, "utf8");
+      args.push("--append-system-prompt", meta.systemPromptPath);
+    } catch {
+      // ignore stale/missing prompt file
+    }
+  }
+
   args.push(meta.task);
 
   let finalText = "";

src/wrapper/cli.test.ts

@@ -107,12 +107,91 @@ test("wrapper marks anthropic child run as a subagent child", async () => {
   assert.equal(captured.flags.PI_SUBAGENTS_CHILD, "1");
 });
 
-test("wrapper ignores stale tool and system prompt metadata", async () => {
+test("wrapper respects tools metadata but ignores stale system prompt file", async () => {
   const captured = await runWrapperWithFakePi("anthropic/claude-sonnet-4-5");
-  assert.equal(captured.flags.argv.includes("--tools"), false);
+  // tools metadata should be passed even if there are no tool binaries installed.
+  assert.equal(captured.flags.argv.includes("--tools"), true);
+  // system prompt file is not present in this test, so the flag should not be passed.
   assert.equal(captured.flags.argv.includes("--append-system-prompt"), false);
 });
 
+test("wrapper passes --append-system-prompt when the prompt file exists", async () => {
+  const dir = await mkdtemp(join(tmpdir(), "pi-subagents-wrapper-"));
+  const metaPath = join(dir, "meta.json");
+  const resultPath = join(dir, "result.json");
+  const capturePath = join(dir, "capture.json");
+  const piPath = join(dir, "pi");
+  const promptPath = join(dir, "system-prompt.md");
+
+  await writeFile(
+    piPath,
+    [
+      `#!${process.execPath}`,
+      "const fs = require('fs');",
+      `const capturePath = ${JSON.stringify(capturePath)};`,
+      "const obj = {",
+      "  PI_SUBAGENTS_GITHUB_COPILOT_INITIATOR: process.env.PI_SUBAGENTS_GITHUB_COPILOT_INITIATOR || '',",
+      "  PI_SUBAGENTS_CHILD: process.env.PI_SUBAGENTS_CHILD || '',",
+      "  argv: process.argv.slice(2)",
+      "};",
+      "fs.writeFileSync(capturePath, JSON.stringify(obj), 'utf8');",
+      "console.log(JSON.stringify({type:'message_end',message:{role:'assistant',content:[{type:'text',text:'done'}],model:'github-copilot/gpt-4o',stopReason:'stop'}}));",
+    ].join("\n"),
+    "utf8",
+  );
+  await chmod(piPath, 0o755);
+
+  // create the system prompt file so the wrapper will pass --append-system-prompt
+  await writeFile(promptPath, "System prompt here", "utf8");
+
+  await writeFile(
+    metaPath,
+    JSON.stringify(
+      {
+        runId: "run-1",
+        mode: "single",
+        task: "inspect auth",
+        cwd: dir,
+        requestedModel: "anthropic/claude-sonnet-4-5",
+        resolvedModel: "anthropic/claude-sonnet-4-5",
+        startedAt: "2026-04-09T00:00:00.000Z",
+        sessionPath: join(dir, "child-session.jsonl"),
+        eventsPath: join(dir, "events.jsonl"),
+        resultPath,
+        stdoutPath: join(dir, "stdout.log"),
+        stderrPath: join(dir, "stderr.log"),
+        transcriptPath: join(dir, "transcript.log"),
+        tools: ["read", "grep"],
+        systemPromptPath: promptPath,
+      },
+      null,
+      2,
+    ),
+    "utf8",
+  );
+
+  const wrapperPath = join(dirname(fileURLToPath(import.meta.url)), "cli.mjs");
+  const child = spawn(process.execPath, [wrapperPath, metaPath], {
+    env: {
+      ...process.env,
+      PATH: dir,
+    },
+    stdio: ["ignore", "pipe", "pipe"],
+  });
+
+  const exitCode = await waitForExit(child);
+  assert.equal(exitCode, 0);
+
+  const captureJson = JSON.parse(await readFile(capturePath, "utf8"));
+  const argv = captureJson.argv;
+  assert.equal(argv.includes("--tools"), true);
+  const toolsIndex = argv.indexOf("--tools");
+  assert.equal(argv[toolsIndex + 1], "read,grep");
+  assert.equal(argv.includes("--append-system-prompt"), true);
+  const idx = argv.indexOf("--append-system-prompt");
+  assert.equal(argv[idx + 1], promptPath);
+});
+
 test("wrapper marks github-copilot child runs as agent-initiated", async () => {
   const captured = await runWrapperWithFakePi("github-copilot/gpt-4o");
   assert.equal(captured.flags.PI_SUBAGENTS_GITHUB_COPILOT_INITIATOR, "agent");

src/wrapper/render.mjs

@@ -1,15 +1,24 @@
 import { createProgressFormatter } from "../progress.mjs";
 
 export function renderHeader(meta) {
-  return [
+  const lines = [
     "=== subagent ===",
     `Task: ${meta.task}`,
+  ];
+
+  if (meta.preset) {
+    lines.push(`Preset: ${meta.preset}`);
+  }
+
+  lines.push(
     `CWD: ${meta.cwd}`,
     `Requested model: ${meta.requestedModel ?? "(default)"}`,
     `Resolved model: ${meta.resolvedModel ?? "(pending)"}`,
     `Session: ${meta.sessionPath}`,
     "---------------------",
-  ].join("\n");
+  );
+
+  return lines.join("\n");
 }
 
 export function createEventLineRenderer() {