From 8e9b4e57941d5d432beb4843356b48dbfdbdda04 Mon Sep 17 00:00:00 2001
From: Jon <57672422+jtbnz@users.noreply.github.com>
Date: Thu, 7 May 2026 09:53:28 +1200
Subject: [PATCH] feat(session): expose LLM response headers on assistant
 messages

---
 packages/opencode/src/session/message-v2.ts | 1 +
 packages/opencode/src/session/processor.ts  | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index 237fb527c078..e329d14de9b8 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -578,6 +578,7 @@ export const Assistant = Schema.Struct({
   structured: Schema.optional(Schema.Any),
   variant: Schema.optional(Schema.String),
   finish: Schema.optional(Schema.String),
+  responseHeaders: Schema.optional(Schema.Record(Schema.String, Schema.String)),
 })
   .annotate({ identifier: "AssistantMessage" })
   .pipe(withStatics((s) => ({ zod: zod(s) })))
diff --git a/packages/opencode/src/session/processor.ts b/packages/opencode/src/session/processor.ts
index f22da92927d2..c05b318cc0e9 100644
--- a/packages/opencode/src/session/processor.ts
+++ b/packages/opencode/src/session/processor.ts
@@ -471,6 +471,8 @@ export const layer: Layer.Layer<
             ctx.assistantMessage.finish = value.finishReason
             ctx.assistantMessage.cost += usage.cost
             ctx.assistantMessage.tokens = usage.tokens
+            if (value.response.headers && Object.keys(value.response.headers).length > 0)
+              ctx.assistantMessage.responseHeaders = value.response.headers
             yield* session.updatePart({
               id: PartID.ascending(),
               reason: value.finishReason,