From 11429e525e6eb20cfc34726366fd800c5b2ebf86 Mon Sep 17 00:00:00 2001
From: Mark IJbema <mark@kilocode.ai>
Date: Tue, 19 May 2026 16:07:16 +0200
Subject: [PATCH] feat(gateway): capture x-kilo-request and x-kilo-session
 headers

Extract the kilocode client's per-message id (`x-kilo-request`) into
`MicrodollarUsageContext.clientRequestId` and accept `x-kilo-session`
as a fallback session id when `x-kilocode-taskid` is absent.

The new `clientRequestId` field has no current consumer; it lands here
as plumbing for the model-experiments attribution write (PR #3325) so
later changes don't have to touch the dozens of `MicrodollarUsageContext`
construction sites in routes, tests, and dev helpers.

`session_id` already feeds existing usage telemetry, so the
`x-kilo-session` fallback is immediately useful for non-kilocode
clients that supply a session header but not a kilocode task id.
---
 apps/web/src/app/api/openrouter/[...path]/route.ts | 12 ++++++++++--
 apps/web/src/lib/ai-gateway/processUsage.types.ts  |  7 +++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/apps/web/src/app/api/openrouter/[...path]/route.ts b/apps/web/src/app/api/openrouter/[...path]/route.ts
index b063c4bb7f2..1738fad9da8 100644
--- a/apps/web/src/app/api/openrouter/[...path]/route.ts
+++ b/apps/web/src/app/api/openrouter/[...path]/route.ts
@@ -223,6 +223,13 @@ export async function POST(request: NextRequest): Promise<NextResponseType<unkno
 
   const modeHeader = extractHeaderAndLimitLength(request, 'x-kilocode-mode');
   const taskId = extractHeaderAndLimitLength(request, 'x-kilocode-taskid') ?? undefined;
+  // Per-message id from the kilocode client. Joinable to PostHog
+  // `Feedback Submitted.parentMessageID`.
+  const clientRequestId = extractHeaderAndLimitLength(request, 'x-kilo-request');
+  // Fallback session id used when `x-kilocode-taskid` is absent (e.g.
+  // non-kilocode clients). `taskId` still wins when both are present.
+  const sessionHeader = extractHeaderAndLimitLength(request, 'x-kilo-session');
+  const machineIdHeader = extractHeaderAndLimitLength(request, 'x-kilocode-machineid');
   let autoModel: string | null = null;
   if (isKiloAutoModel(requestedModelLowerCased)) {
     autoModel = requestedModelLowerCased;
@@ -436,16 +443,17 @@ export async function POST(request: NextRequest): Promise<NextResponseType<unkno
     project_id: projectId,
     status_code: null,
     editor_name: extractHeaderAndLimitLength(request, 'x-kilocode-editorname'),
-    machine_id: extractHeaderAndLimitLength(request, 'x-kilocode-machineid'),
+    machine_id: machineIdHeader,
     user_byok: !!userByok,
     has_tools: (requestBodyParsed.body.tools?.length ?? 0) > 0,
     botId,
     tokenSource,
     feature,
-    session_id: taskId ?? null,
+    session_id: taskId ?? sessionHeader ?? null,
     mode: modeHeader,
     auto_model: autoModel,
     ttfb_ms: null,
+    clientRequestId,
   };
 
   setTag('ui.ai_model', requestBodyParsed.body.model);
diff --git a/apps/web/src/lib/ai-gateway/processUsage.types.ts b/apps/web/src/lib/ai-gateway/processUsage.types.ts
index f88ea58ec62..e7bbba77db3 100644
--- a/apps/web/src/lib/ai-gateway/processUsage.types.ts
+++ b/apps/web/src/lib/ai-gateway/processUsage.types.ts
@@ -144,6 +144,13 @@ export type MicrodollarUsageContext = {
   auto_model: string | null;
   /** Time to first byte from the upstream provider, in milliseconds. Set after the upstream request returns. */
   ttfb_ms: number | null;
+  /**
+   * Client-supplied per-message id from the `x-kilo-request` header.
+   * Joinable to PostHog `Feedback Submitted.parentMessageID`. Optional
+   * because pre-existing construction sites (routes, tests, dev helpers)
+   * do not need to know about it.
+   */
+  clientRequestId?: string | null;
 };
 
 export type CoreUsageWithMetaData = {