refactor(http): one drain loop and one closed-response guard for the local servers

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to `@tangle-network/agent-eval` and its sibling `agent-eval-
 
 ---
 
+## [0.167.1] — 2026-08-21
+
+### Changed
+
+- `waitForActiveHandlers` and `sendJsonIfOpen` had three byte-identical private copies each, one per local HTTP server (`src/analyst/trace-tool-callback.ts`, `src/campaign/external-optimizer-callback.ts`, `src/campaign/external-optimizer-model-proxy.ts`). Both now live in `src/campaign/external-optimizer-http.ts`, the module all three already imported `closeServer`, `listenLocal`, and `sendJson` from. The drain loop re-reads the handler set on every pass because a running handler can register another; a copy that awaited one snapshot would let the caller close the server with work outstanding. No behavior change and no export change: the helpers are internal to that module's consumers.
+
+---
+
 ## [0.167.0] — 2026-08-21
 
 ### Changed

clients/python/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "agent-eval-rpc"
-version = "0.167.0"
+version = "0.167.1"
 description = "Python RPC client, official optimizer bridge, and DSPy metric adapter for @tangle-network/agent-eval."
 readme = "README.md"
 requires-python = ">=3.10"

clients/python/src/agent_eval_rpc/__init__.py

@@ -53,7 +53,7 @@
 try:
     __version__ = version("agent-eval-rpc")
 except PackageNotFoundError:
-    __version__ = "0.167.0"
+    __version__ = "0.167.1"
 
 __all__ = [
     "Client",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@tangle-network/agent-eval",
-  "version": "0.167.0",
+  "version": "0.167.1",
   "description": "Evaluate and improve AI agents from runs, traces, judges, and feedback. Compare candidates, cluster failures, measure lift, and gate releases.",
   "homepage": "https://github.com/tangle-network/agent-eval#readme",
   "repository": {

src/analyst/benchmark-implementation.ts

@@ -10,7 +10,7 @@ export const ANALYST_BENCHMARK_DEPENDENCY_LOCK_FILES = Object.freeze([
 ])
 
 export const ANALYST_BENCHMARK_DEPENDENCY_LOCK_SHA256 =
-  '5487ec58c4a939ece38536a982a9a72e3d59363a2ed8677c6ad2aaa9699c06f1'
+  'a372aba7edb147c768813488fa7c69395f093f4c2b9bb9862aff2d3b468be47a'
 
 /** The published benchmark evidence was produced at this package version, by
  * the retired one-shot direct runner, before trace analysts moved to the
@@ -139,7 +139,7 @@ export const ANALYST_BENCHMARK_IMPLEMENTATION_FILES = Object.freeze([
 ])
 
 export const ANALYST_BENCHMARK_IMPLEMENTATION_SHA256 =
-  'c3c6778b7102a635706b76a8bd5a1f0375cd84e30f900a4026c7939cb6fb04b9'
+  '2ab66a98fac14974e8e3fde86600899a38a1cbba2957bed3afad44261108c43e'
 
 export function analystBenchmarkImplementationDigest() {
   return ANALYST_BENCHMARK_IMPLEMENTATION_SHA256

src/analyst/trace-tool-callback.ts

@@ -4,7 +4,12 @@ import {
   type ExternalOptimizerCallbackLimits,
   resolveExternalOptimizerCallbackLimits,
 } from '../campaign/external-optimizer-contracts'
-import { closeServer, listenLocal, sendJson } from '../campaign/external-optimizer-http'
+import {
+  closeServer,
+  listenLocal,
+  sendJsonIfOpen,
+  waitForActiveHandlers,
+} from '../campaign/external-optimizer-http'
 import type { TraceAnalysisToolDescriptor } from '../trace-analyst/tools'
 
 export interface TraceToolCallback {
@@ -144,12 +149,6 @@ export async function startTraceToolCallback(args: {
   }
 }
 
-async function waitForActiveHandlers(activeHandlers: Set<Promise<void>>): Promise<void> {
-  while (activeHandlers.size > 0) {
-    await Promise.allSettled([...activeHandlers])
-  }
-}
-
 function readJson(request: IncomingMessage, maxRequestBytes: number): Promise<unknown> {
   return new Promise((resolve, reject) => {
     let size = 0
@@ -174,11 +173,6 @@ function readJson(request: IncomingMessage, maxRequestBytes: number): Promise<un
   })
 }
 
-function sendJsonIfOpen(response: ServerResponse, status: number, body: unknown): void {
-  if (response.destroyed || response.writableEnded) return
-  sendJson(response, status, body)
-}
-
 function isRecord(value: unknown): value is Record<string, unknown> {
   return typeof value === 'object' && value !== null && !Array.isArray(value)
 }

src/campaign/external-optimizer-callback.ts

@@ -10,7 +10,12 @@ import {
   isRecord,
   resolveExternalOptimizerCallbackLimits,
 } from './external-optimizer-contracts'
-import { closeServer, listenLocal, sendJson } from './external-optimizer-http'
+import {
+  closeServer,
+  listenLocal,
+  sendJsonIfOpen,
+  waitForActiveHandlers,
+} from './external-optimizer-http'
 
 type UnsequencedObservation = ExternalOptimizerEvaluationObservation extends infer T
   ? T extends ExternalOptimizerEvaluationObservation
@@ -233,17 +238,6 @@ async function handleCallback<TResponse>(
   }
 }
 
-async function waitForActiveHandlers(activeHandlers: Set<Promise<void>>): Promise<void> {
-  while (activeHandlers.size > 0) {
-    await Promise.allSettled([...activeHandlers])
-  }
-}
-
-function sendJsonIfOpen(response: ServerResponse, status: number, body: unknown): void {
-  if (response.destroyed || response.writableEnded) return
-  sendJson(response, status, body)
-}
-
 function readJson(request: IncomingMessage, maxRequestBytes: number): Promise<unknown> {
   return new Promise((resolvePromise, reject) => {
     let size = 0

src/campaign/external-optimizer-http.ts

@@ -25,3 +25,28 @@ export function sendJson(response: ServerResponse, status: number, body: unknown
   response.writeHead(status, { 'content-type': 'application/json; charset=utf-8' })
   response.end(JSON.stringify(body))
 }
+
+/**
+ * Send a JSON body only while the response can still take one.
+ *
+ * A handler that lost its client — the request was aborted, or the response
+ * already ended — must not write again; Node throws `ERR_STREAM_WRITE_AFTER_END`
+ * and the throw escapes into the server's error path rather than the caller's.
+ */
+export function sendJsonIfOpen(response: ServerResponse, status: number, body: unknown): void {
+  if (response.destroyed || response.writableEnded) return
+  sendJson(response, status, body)
+}
+
+/**
+ * Wait until every in-flight handler has settled.
+ *
+ * Re-reads the set on each pass: a handler that is still running can register
+ * another, so awaiting one snapshot would return while work is outstanding and
+ * the caller would close the server under it.
+ */
+export async function waitForActiveHandlers(activeHandlers: Set<Promise<void>>): Promise<void> {
+  while (activeHandlers.size > 0) {
+    await Promise.allSettled([...activeHandlers])
+  }
+}

src/campaign/external-optimizer-model-proxy.ts

@@ -35,7 +35,12 @@ import {
   type ExternalOptimizerWireCounts,
   isRecord,
 } from './external-optimizer-contracts'
-import { closeServer, listenLocal, sendJson } from './external-optimizer-http'
+import {
+  closeServer,
+  listenLocal,
+  sendJsonIfOpen,
+  waitForActiveHandlers,
+} from './external-optimizer-http'
 
 const MODEL_PROXY_PATHS = new Set(['/v1/chat/completions', '/v1/responses'])
 type ModelProxyPath = '/v1/chat/completions' | '/v1/responses' | '/v1/messages'
@@ -474,17 +479,6 @@ async function handleModelProxyRequest(args: {
   }
 }
 
-async function waitForActiveHandlers(activeHandlers: Set<Promise<void>>): Promise<void> {
-  while (activeHandlers.size > 0) {
-    await Promise.allSettled([...activeHandlers])
-  }
-}
-
-function sendJsonIfOpen(response: ServerResponse, status: number, body: unknown): void {
-  if (response.destroyed || response.writableEnded) return
-  sendJson(response, status, body)
-}
-
 async function forwardModelProxyRequest(args: {
   call: ExternalOptimizerModelCall
   callId: string