Adding support for herdr - agents in new tabs

pi-extension/subagents/index.ts

@@ -24,7 +24,9 @@ import {
   closeSurface,
   shellEscape,
   readScreen,
-} from "./tmux.ts";
+  getMuxBackend,
+  wrapWithCompletionFile,
+} from "./surface.ts";
 
 import {
   countSessionEntryLines,
@@ -497,10 +499,15 @@ function widgetIcon(kind: StatusSnapshot["kind"]): string {
  * (for example direnv/devenv), so the delay is configurable for users who hit
  * dropped commands. Keep the historical default at 500ms.
  */
+function defaultShellReadyDelayMs(backend: ReturnType<typeof getMuxBackend>): number {
+  return backend === "herdr" ? 1000 : 500;
+}
+
 function getShellReadyDelayMs(): number {
   const raw = process.env.PI_SUBAGENT_SHELL_READY_DELAY_MS?.trim();
   const parsed = raw ? Number.parseInt(raw, 10) : Number.NaN;
-  return Number.isFinite(parsed) && parsed >= 0 ? parsed : 500;
+  if (Number.isFinite(parsed) && parsed >= 0) return parsed;
+  return defaultShellReadyDelayMs(getMuxBackend());
 }
 
 function muxUnavailableResult() {
@@ -508,10 +515,10 @@ function muxUnavailableResult() {
     content: [
       {
         type: "text" as const,
-        text: `Subagents require tmux. ${muxSetupHint()}`,
+        text: `Subagents require a supported terminal multiplexer. ${muxSetupHint()}`,
       },
     ],
-    details: { error: "tmux not available" },
+    details: { error: "terminal multiplexer not available" },
   };
 }
 
@@ -618,6 +625,7 @@ interface RunningSubagent {
   abortController?: AbortController;
   cli?: string;
   sentinelFile?: string;
+  completionFile?: string;
   statusState: SubagentStatusState;
   /**
    * When true, status transitions (stalled/recovered) do not wake the parent
@@ -1008,7 +1016,7 @@ function steerSubagent(
   } catch (error: any) {
     return {
       error:
-        `Failed to deliver message to subagent "${running.name}" via tmux: ` +
+        `Failed to deliver message to subagent "${running.name}" via the terminal surface: ` +
         `${error?.message ?? String(error)}`,
     };
   }
@@ -1121,6 +1129,7 @@ function resolveResumeLaunchBehavior(): { autoExit: boolean; interactive: boolea
 
 export const __test__ = {
   borderLine,
+  defaultShellReadyDelayMs,
   getShellReadyDelayMs,
   renderSubagentWidgetLines,
   loadAgentDefaults,
@@ -1141,6 +1150,7 @@ export const __test__ = {
   handleSubagentSteer,
   resolveResultPresentation,
   resolveResumeLaunchBehavior,
+  wrapWithCompletionFile,
   runningSubagents,
   formatElapsed,
   formatTokens,
@@ -1160,7 +1170,7 @@ function startWidgetRefresh() {
 }
 
 /**
- * Launch a subagent: creates the multiplexer pane, builds the command, and
+ * Launch a subagent: creates a terminal surface, builds the command, and
  * sends it. Returns a RunningSubagent — does NOT poll.
  *
  * Call watchSubagent() on the returned object to observe completion.
@@ -1184,6 +1194,8 @@ async function launchSubagent(
   if (!sessionFile) throw new Error("No session file");
   const sessionId = ctx.sessionManager.getSessionId();
   const artifactDir = getArtifactDir(ctx.sessionManager.getSessionDir(), sessionId);
+  const completionFile = join(artifactDir, "subagent-exits", `${id}.exit-code`);
+  mkdirSync(dirname(completionFile), { recursive: true });
 
   const { effectiveCwd, localAgentDir, effectiveAgentDir } = resolveSubagentPaths(params, agentDefs);
   const targetCwdForSession = effectiveCwd ?? ctx.cwd;
@@ -1201,14 +1213,15 @@ async function launchSubagent(
   ].join("-");
   const subagentSessionFile = join(sessionDir, `${timestamp}_${uuid}.jsonl`);
 
-  // Use pre-created surface (parallel mode) or create a new one.
-  // For new surfaces, pause briefly so the shell is ready before sending the command.
+  // Use a pre-created surface or create a new one. New shells need a brief
+  // startup window before terminal input is reliable.
   const surfacePreCreated = !!options?.surface;
   const surface = options?.surface ?? createSurface(params.name);
   if (!surfacePreCreated) {
     await new Promise<void>((resolve) => setTimeout(resolve, getShellReadyDelayMs()));
   }
 
+  try {
   const launchBehavior = resolveLaunchBehavior(params, agentDefs);
 
   if (launchBehavior.seededSessionMode) {
@@ -1271,7 +1284,7 @@ async function launchSubagent(
     cmdParts.push(shellEscape(params.task));
 
     const cdPrefix = effectiveCwd ? `cd ${shellEscape(effectiveCwd)} && ` : "";
-    const command = `${cdPrefix}${cmdParts.join(" ")}; echo '__SUBAGENT_DONE_'$?'__'`;
+    const command = wrapWithCompletionFile(`${cdPrefix}${cmdParts.join(" ")}`, completionFile);
 
     const launchScriptName = `${(params.name || "subagent")
       .toLowerCase()
@@ -1301,6 +1314,7 @@ async function launchSubagent(
       launchScriptFile,
       cli: "claude",
       sentinelFile,
+      completionFile,
       interactive: effectiveInteractive,
       statusState: createStatusState({
         source: "claude",
@@ -1414,7 +1428,7 @@ async function launchSubagent(
   const cdPrefix = effectiveCwd ? `cd ${shellEscape(effectiveCwd)} && ` : "";
 
   const piCommand = cdPrefix + envPrefix + parts.join(" ");
-  const command = `${piCommand}; echo '__SUBAGENT_DONE_'$?'__'`;
+  const command = wrapWithCompletionFile(piCommand, completionFile);
   const launchScriptName = `${(params.name || "subagent")
     .toLowerCase()
     .replace(/[^a-z0-9\s-]/g, "")
@@ -1442,6 +1456,7 @@ async function launchSubagent(
     sessionFile: subagentSessionFile,
     launchScriptFile,
     activityFile,
+    completionFile,
     interactive: effectiveInteractive,
     statusState: createStatusState({
       source: "pi",
@@ -1451,6 +1466,17 @@ async function launchSubagent(
 
   runningSubagents.set(id, running);
   return running;
+  } catch (error) {
+    runningSubagents.delete(id);
+    if (!surfacePreCreated) {
+      try {
+        closeSurface(surface);
+      } catch {
+        // Preserve the launch error; cleanup is best-effort.
+      }
+    }
+    throw error;
+  }
 }
 
 /**
@@ -1532,6 +1558,7 @@ async function watchSubagent(
       interval: 1000,
       sessionFile,
       sentinelFile: running.sentinelFile,
+      completionFile: running.completionFile,
       onTick() {
         observeRunningSubagent(running);
         deliverPendingQuestion(running);
@@ -2152,6 +2179,7 @@ export default function subagentsExtension(pi: ExtensionAPI) {
         const surface = createSurface(name);
         await new Promise<void>((resolve) => setTimeout(resolve, getShellReadyDelayMs()));
 
+        try {
         // Build pi resume command
         const parts = ["pi", "--session", shellEscape(sessionPath)];
 
@@ -2162,7 +2190,9 @@ export default function subagentsExtension(pi: ExtensionAPI) {
         const sessionId = ctx.sessionManager.getSessionId();
         const artifactDir = getArtifactDir(ctx.sessionManager.getSessionDir(), sessionId);
         const activityFile = getSubagentActivityFile(artifactDir, id);
+        const completionFile = join(artifactDir, "subagent-exits", `${id}.exit-code`);
         mkdirSync(dirname(activityFile), { recursive: true });
+        mkdirSync(dirname(completionFile), { recursive: true });
 
         // Replay the model, identity, and default-deny tool/extension sandbox.
         applySandboxToParts(parts, loadout, { artifactDir, name });
@@ -2212,7 +2242,10 @@ export default function subagentsExtension(pi: ExtensionAPI) {
         // operate where they did before.
         const resumeCdPrefix = loadout.cwd ? `cd ${shellEscape(loadout.cwd)} && ` : "";
 
-        const command = `${resumeCdPrefix}${resumeEnvPrefix}${parts.join(" ")}; echo '__SUBAGENT_DONE_'$?'__'`;
+        const command = wrapWithCompletionFile(
+          `${resumeCdPrefix}${resumeEnvPrefix}${parts.join(" ")}`,
+          completionFile,
+        );
         const launchScriptFile = join(
           artifactDir,
           "subagent-scripts",
@@ -2244,6 +2277,7 @@ export default function subagentsExtension(pi: ExtensionAPI) {
           sessionFile: sessionPath,
           launchScriptFile,
           activityFile,
+          completionFile,
           interactive,
           statusState: createStatusState({
             source: "pi",
@@ -2316,6 +2350,15 @@ export default function subagentsExtension(pi: ExtensionAPI) {
             status: "started",
           },
         };
+        } catch (error) {
+          runningSubagents.delete(id);
+          try {
+            closeSurface(surface);
+          } catch {
+            // Preserve the resume error; cleanup is best-effort.
+          }
+          throw error;
+        }
       },
     });