perf(subagent): sort sub-agent tool wire order too

SubAgentDirector passed its tool definitions to super unsorted, so leaf
workers kept shipping discovery order while the main chat director had
been pinned. Same helper, same reason.

CL-7868

Author: TheGreatAxios

src/agent/director.ts

@@ -55,7 +55,9 @@ const logger = getLogger([LOG_NAMESPACE_ROOT, "agent", "director"]);
 // falling to 2.1% on a reorder alone. Tool discovery order is not stable across
 // turns (MCP connect order, plugin load order, map iteration), so the wire
 // order is pinned by name. See CL-7868.
-function stableToolOrder(tools: readonly ToolDefinition[]): ToolDefinition[] {
+export function stableToolOrder(
+  tools: readonly ToolDefinition[],
+): ToolDefinition[] {
   return [...tools].sort((a, b) => a.name.localeCompare(b.name));
 }
 

src/subagent/nudge-director.ts

@@ -20,6 +20,7 @@ import {
   createCompactionGovernor,
   type CompactionGovernor,
 } from "../agent/compaction.js";
+import { stableToolOrder } from "../agent/director.js";
 import { onTurnBoundary } from "../agent/reactor-events.js";
 import { createCorbitsRetryPolicy } from "../agent/retry-policy.js";
 import {
@@ -235,12 +236,13 @@ export class SubAgentDirector extends DefaultDirector {
     requirePlanSubstance = false,
     retryPolicy: RetryPolicy = createCorbitsRetryPolicy(),
   ) {
-    super(systemPrompt, toolDefinitions, {});
+    const orderedTools = stableToolOrder(toolDefinitions);
+    super(systemPrompt, orderedTools, {});
     this._systemPrompt = systemPrompt;
     this.compaction = createCompactionGovernor(
       requestContinuation,
       systemPrompt,
-      toolDefinitions,
+      orderedTools,
     );
     this.stallTimeoutMs = stallTimeoutMs;
     this.now = now;