fix(session): fall back when generated titles stay default

packages/opencode/src/session/prompt.ts

@@ -336,7 +336,7 @@ export namespace SessionPrompt {
 
       step++
       if (step === 1)
-        ensureTitle({
+        await ensureTitle({
           session,
           modelID: lastUser.model.modelID,
           providerID: lastUser.model.providerID,
@@ -1983,6 +1983,26 @@ NOTE: At any point in time through this workflow you should feel free to ask the
     providerID: ProviderID
     modelID: ModelID
   }) {
+    function fallback(msg: MessageV2.WithParts) {
+      const line = msg.parts
+        .filter((part) => part.type === "text")
+        .flatMap((part) => part.text.split("\n"))
+        .map((line) => line.trim())
+        .find((line) => line.length > 0)
+      if (!line) return
+      const title = line
+        .replace(/[\s\-:;,.!?]+$/g, "")
+        .split(/\s+/)
+        .filter(Boolean)
+        .slice(0, 5)
+        .join(" ")
+      if (!title) return
+      return Session.setTitle({ sessionID: input.session.id, title: title.length > 100 ? title.substring(0, 97) + "..." : title }).catch((err) => {
+        if (NotFoundError.isInstance(err)) return
+        throw err
+      })
+    }
+
     if (input.session.parentID) return
     if (!Session.isDefaultTitle(input.session.title)) return
 
@@ -2052,5 +2072,7 @@ NOTE: At any point in time through this workflow you should feel free to ask the
     } catch (error) {
       log.error("failed to generate title", { error })
     }
+
+    return fallback(firstRealUser)
   }
 }

packages/opencode/test/session/prompt.test.ts

@@ -1,5 +1,5 @@
 import path from "path"
-import { describe, expect, test } from "bun:test"
+import { describe, expect, spyOn, test } from "bun:test"
 import { NamedError } from "@opencode-ai/util/error"
 import { fileURLToPath } from "url"
 import { Instance } from "../../src/project/instance"
@@ -9,84 +9,19 @@
 import { SessionPrompt } from "../../src/session/prompt"
 import { Log } from "../../src/util/log"
 import { tmpdir } from "../fixture/fixture"
+import { LLM } from "../../src/session/llm"
+import { Filesystem } from "../../src/util/filesystem"
 
 Log.init({ print: false })
 
-function defer<T>() {
-  let resolve!: (value: T | PromiseLike<T>) => void
-  const promise = new Promise<T>((done) => {
-    resolve = done
-  })
-  return { promise, resolve }
-}
-
-function chat(text: string) {
-  const payload =
-    [
-      `data: ${JSON.stringify({
-        id: "chatcmpl-1",
-        object: "chat.completion.chunk",
-        choices: [{ delta: { role: "assistant" } }],
-      })}`,
-      `data: ${JSON.stringify({
-        id: "chatcmpl-1",
-        object: "chat.completion.chunk",
-        choices: [{ delta: { content: text } }],
-      })}`,
-      `data: ${JSON.stringify({
-        id: "chatcmpl-1",
-        object: "chat.completion.chunk",
-        choices: [{ delta: {}, finish_reason: "stop" }],
-      })}`,
-      "data: [DONE]",
-    ].join("\n\n") + "\n\n"
-
-  const encoder = new TextEncoder()
-  return new ReadableStream<Uint8Array>({
-    start(ctrl) {
-      ctrl.enqueue(encoder.encode(payload))
-      ctrl.close()
-    },
-  })
-}
-
-function hanging(ready: () => void) {
-  const encoder = new TextEncoder()
-  let timer: ReturnType<typeof setTimeout> | undefined
-  const first =
-    `data: ${JSON.stringify({
-      id: "chatcmpl-1",
-      object: "chat.completion.chunk",
-      choices: [{ delta: { role: "assistant" } }],
-    })}` + "\n\n"
-  const rest =
-    [
-      `data: ${JSON.stringify({
-        id: "chatcmpl-1",
-        object: "chat.completion.chunk",
-        choices: [{ delta: { content: "late" } }],
-      })}`,
-      `data: ${JSON.stringify({
-        id: "chatcmpl-1",
-        object: "chat.completion.chunk",
-        choices: [{ delta: {}, finish_reason: "stop" }],
-      })}`,
-      "data: [DONE]",
-    ].join("\n\n") + "\n\n"
-
-  return new ReadableStream<Uint8Array>({
-    start(ctrl) {
-      ctrl.enqueue(encoder.encode(first))
-      ready()
-      timer = setTimeout(() => {
-        ctrl.enqueue(encoder.encode(rest))
-        ctrl.close()
-      }, 10000)
-    },
-    cancel() {
-      if (timer) clearTimeout(timer)
-    },
-  })
+async function loadFixture(providerID: string, modelID: string) {
+  const fixturePath = path.join(import.meta.dir, "../tool/fixtures/models-api.json")
+  const data = await Filesystem.readJson<Record<string, { models: Record<string, unknown> }>>(fixturePath)
+  const provider = data[providerID]
+  if (!provider) throw new Error(`Missing provider in fixture: ${providerID}`)
+  const model = provider.models[modelID]
+  if (!model) throw new Error(`Missing model in fixture: ${modelID}`)
+  return model
 }
 
 describe("session.prompt missing file", () => {
@@ -237,7 +172,7 @@
           return new Response("not found", { status: 404 })
         }
         calls++
         return new Response(chat("packages/opencode/src/session/processor.ts"), {
           status: 200,
           headers: { "Content-Type": "text/event-stream" },
         })
@@ -295,7 +230,7 @@
   })
 
   test("records aborted errors when prompt is cancelled mid-stream", async () => {
     const ready = defer<void>()
     const server = Bun.serve({
       port: 0,
       fetch(req) {
@@ -516,3 +451,73 @@
     })
   }, 30000)
 })
+
+describe("session title fallback", () => {
+  test("falls back to the first few words when title generation returns nothing", async () => {
+    const model = await loadFixture("openai", "gpt-5.2")
+    const stream = spyOn(LLM, "stream")
+      .mockResolvedValueOnce({
+        text: Promise.resolve(""),
+      } as Awaited<ReturnType<typeof LLM.stream>>)
+      .mockResolvedValueOnce({
+        fullStream: (async function* () {
+          yield { type: "start" }
+          yield {
+            type: "finish-step",
+            finishReason: "stop",
+            usage: { inputTokens: 1, outputTokens: 1, totalTokens: 2 },
+            providerMetadata: {},
+          }
+          yield { type: "finish" }
+        })(),
+      } as unknown as Awaited<ReturnType<typeof LLM.stream>>)
+
+    await using tmp = await tmpdir({
+      git: true,
+      config: {
+        enabled_providers: ["openai"],
+        provider: {
+          openai: {
+            options: {
+              apiKey: "test-openai-key",
+              models: {
+                "gpt-5.2": model,
+              },
+            },
+          },
+        },
+        agent: {
+          build: {
+            model: "openai/gpt-5.2",
+          },
+        },
+      },
+    })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+
+        await SessionPrompt.prompt({
+          sessionID: session.id,
+          agent: "build",
+          parts: [{ type: "text", text: "All of my sessions are names new session is the a telemetry package sideffect?" }],
+        })
+
+        expect(stream).toHaveBeenCalledTimes(2)
+
+        let info = await Session.get(session.id)
+        for (let i = 0; i < 20 && info?.title !== "All of my sessions are"; i++) {
+          await new Promise((resolve) => setTimeout(resolve, 50))
+          info = await Session.get(session.id)
+        }
+        expect(info?.title).toBe("All of my sessions are")
+
+        await Session.remove(session.id)
+      },
+    })
+
+    stream.mockRestore()
+  })
+})