feat: write subagent completion receipt state

scripts/subagent_delivery_watchdog.mjs

@@ -122,6 +122,66 @@ function writeDispatchReceiptState(payload) {
   };
 }
 
+function writeCompletionReceiptState(payload) {
+  if (!payload || typeof payload !== 'object') {
+    return null;
+  }
+
+  const { runId } = payload;
+  const completionReceivedAt = payload.completionReceivedAt ?? payload.completionReceiptAt ?? null;
+  const forwardedToMain = payload.forwardedToMain;
+  const resultSource = payload.resultSource;
+
+  if (typeof runId !== 'string' || runId.length === 0) {
+    return null;
+  }
+
+  const completionUpdates = {};
+
+  if (typeof completionReceivedAt === 'string' && completionReceivedAt.length > 0) {
+    completionUpdates.completionReceivedAt = completionReceivedAt;
+  }
+
+  if (typeof forwardedToMain === 'boolean') {
+    completionUpdates.forwardedToMain = forwardedToMain;
+  }
+
+  if (typeof resultSource === 'string' && resultSource.length > 0) {
+    completionUpdates.resultSource = resultSource;
+  }
+
+  if (Object.keys(completionUpdates).length === 0) {
+    return null;
+  }
+
+  fs.mkdirSync(STATE_DIR, { recursive: true });
+
+  const statePath = path.join(STATE_DIR, `${runId}.json`);
+  let currentRecord = {};
+
+  if (fs.existsSync(statePath)) {
+    try {
+      currentRecord = JSON.parse(fs.readFileSync(statePath, 'utf8'));
+    } catch {
+      currentRecord = {};
+    }
+  }
+
+  const nextRecord = {
+    ...currentRecord,
+    runId,
+    ...completionUpdates,
+  };
+
+  fs.writeFileSync(statePath, `${JSON.stringify(nextRecord, null, 2)}\n`, 'utf8');
+
+  return {
+    statePath,
+    record: nextRecord,
+    updatedFields: Object.keys(completionUpdates),
+  };
+}
+
 function main() {
   const args = parseArgs(process.argv.slice(2));
 
@@ -133,16 +193,25 @@ function main() {
   const input = tryReadInput(args.input);
   const inputPayload = input.exists ? tryParseJson(input.content) : null;
   const dispatchWrite = writeDispatchReceiptState(inputPayload);
+  const completionWrite = writeCompletionReceiptState(inputPayload);
 
   if ('content' in input) {
     delete input.content;
   }
 
+  const records = [];
+  if (dispatchWrite) {
+    records.push(dispatchWrite.record);
+  }
+  if (completionWrite) {
+    records.push(completionWrite.record);
+  }
+
   const response = {
     ok: true,
     tool: 'subagent_delivery_watchdog',
-    version: 'skeleton-v2',
-    mode: 'dispatch-receipt-write',
+    version: 'skeleton-v3',
+    mode: 'receipt-write',
     args: {
       compact: args.compact,
       input: args.input,
@@ -150,9 +219,10 @@ function main() {
     input,
     result: {
       status: 'not_implemented',
-      message: 'Dispatch receipt write is implemented; status recompute remains pending.',
-      records: dispatchWrite ? [dispatchWrite.record] : [],
+      message: 'Dispatch and completion receipt writes are implemented; status recompute remains pending.',
+      records,
       dispatchReceiptWrite: dispatchWrite,
+      completionReceiptWrite: completionWrite,
     },
   };