fix(core): attribute one-shot generation requests (#48358)

Co-authored-by: OpenCode Agent <opencode-agent[bot]@users.noreply.github.com>

packages/core/src/generate.ts

@@ -1,6 +1,7 @@
 export * as Generate from "./generate.js"
 
 import { LLM, LLMClient, AIError } from "@opencode/ai"
+import { SessionID } from "@opencode/schema/session-id"
 import { Context, Effect, Layer, Schema } from "effect"
 import { makeLocationNode } from "@opencode/util/effect/app-node"
 import { llmClient } from "./effect/app-node-platform.js"
@@ -60,15 +61,24 @@ export const layer = Layer.effect(
             ? `Model unavailable: ${input.model.providerID}/${input.model.id}`
             : "No model specified and no supported model is available",
         })
-      const response = yield* llm.generate(LLM.request({ model: resolved.model, prompt: input.prompt })).pipe(
-        Effect.mapError(
-          (error: AIError) =>
-            new UnavailableError({
-              message: error.message,
-              service: resolved.ref.providerID,
-            }),
-        ),
-      )
+      const response = yield* llm
+        .generate(
+          LLM.request({
+            model: resolved.model,
+            prompt: input.prompt,
+            // Gateways require session attribution even for a stateless call; no Session is stored.
+            http: { headers: { "x-opencode-session": SessionID.create() } },
+          }),
+        )
+        .pipe(
+          Effect.mapError(
+            (error: AIError) =>
+              new UnavailableError({
+                message: error.message,
+                service: resolved.ref.providerID,
+              }),
+          ),
+        )
       return response.text
     })
 

packages/core/test/generate.test.ts

@@ -1,5 +1,6 @@
 import { expect } from "bun:test"
-import { LanguageModel } from "@opencode/ai"
+import { LanguageModel, LLMClient } from "@opencode/ai"
+import { RequestExecutor } from "@opencode/ai/route"
 import { OpenAIChat } from "@opencode/ai/protocols"
 import { TestLLM } from "@opencode/ai/testing"
 import { AISDK } from "@opencode/core/aisdk"
@@ -10,6 +11,7 @@ import { ID, Info, Model, Ref } from "@opencode/core/model"
 import { Provider } from "@opencode/core/provider"
 import { Npm } from "@opencode/util/npm"
 import { Effect, Layer } from "effect"
+import { HttpClient, HttpClientResponse } from "effect/unstable/http"
 import { testEffect } from "./lib/effect"
 
 const selected = Info.make({
@@ -89,3 +91,56 @@ resolverIt.effect("resolves dynamic models with their catalog metadata", () =>
     })
   }),
 )
+
+testEffect(Layer.empty).effect("attributes each stateless completion without creating a stored session", () =>
+  Effect.gen(function* () {
+    const sessions: string[] = []
+    const http = Layer.succeed(
+      HttpClient.HttpClient,
+      HttpClient.make((request) =>
+        Effect.sync(() => {
+          const session = request.headers["x-opencode-session"]
+          if (!session)
+            return HttpClientResponse.fromWeb(
+              request,
+              Response.json(
+                {
+                  error: { type: "MissingSessionID", message: "Session ID is required" },
+                },
+                { status: 400 },
+              ),
+            )
+          sessions.push(session)
+          return HttpClientResponse.fromWeb(
+            request,
+            new Response(
+              `data: ${JSON.stringify({
+                id: "completion",
+                object: "chat.completion.chunk",
+                created: 1,
+                model: "gemini",
+                choices: [{ index: 0, delta: { content: "OK" }, finish_reason: "stop" }],
+              })}\n\ndata: [DONE]\n\n`,
+              { headers: { "content-type": "text/event-stream" } },
+            ),
+          )
+        }),
+      ),
+    )
+    const native = LLMClient.layer.pipe(Layer.provide(RequestExecutor.layer.pipe(Layer.provide(http))))
+    yield* Effect.gen(function* () {
+      const generate = yield* Generate.Service
+      for (let index = 0; index < 2; index++) {
+        expect(
+          yield* generate.text({
+            prompt: "Return exactly OK",
+            model: Ref.make({ providerID: selected.providerID, id: selected.id }),
+          }),
+        ).toBe("OK")
+      }
+    }).pipe(Effect.provide(Generate.layer.pipe(Layer.provide(Layer.merge(resolver, native)))))
+    expect(sessions).toHaveLength(2)
+    expect(sessions[0]).toStartWith("ses_")
+    expect(sessions[1]).not.toBe(sessions[0])
+  }),
+)