fix: Phase 2 — backport 5 high-priority upstream bug fixes

WHAT_WE_DID.md

@@ -16,3 +16,4 @@ CAS, edit graph, context editing (6 ops), side threads, objective tracker, class
 - **#24:** Zod v4 migration (zodToJsonSchema → z.toJSONSchema), 25 Frankencode unit tests, tracking docs cleanup
 - **#25:** Upstream catalogue (162 commits + ~195 PRs), security audit (2 CVEs, 5 issues), 6-phase roadmap
 - **#26:** Phase 1 security fixes: S1 symlink bypass, S2 exec→spawn, S4 server auth, S5 sensitive deny-list, S3 warning (13 tests)
+- **#27:** Phase 2 upstream fixes: prompt parts (#17815), thinkingConfig guard (#18283), chunk timeout (#18264), error messages (#18165), event queue (#18259)

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -13,6 +13,7 @@ import { MessageID, PartID } from "@/session/schema"
 import { createStore, produce } from "solid-js/store"
 import { useKeybind } from "@tui/context/keybind"
 import { usePromptHistory, type PromptInfo } from "./history"
+import { assign } from "./part"
 import { usePromptStash } from "./stash"
 import { DialogStash } from "../dialog-stash"
 import { type AutocompleteRef, Autocomplete } from "./autocomplete"
@@ -643,10 +644,7 @@ export function Prompt(props: PromptProps) {
               type: "text",
               text: inputText,
             },
-            ...nonTextParts.map((x) => ({
-              id: PartID.ascending(),
-              ...x,
-            })),
+            ...nonTextParts.map(assign),
           ],
         })
         .catch(() => {})

packages/opencode/src/cli/cmd/tui/component/prompt/part.ts

@@ -0,0 +1,16 @@
+import { PartID } from "@/session/schema"
+import type { PromptInfo } from "./history"
+
+type Item = PromptInfo["parts"][number]
+
+export function strip(part: Item & { id: string; messageID: string; sessionID: string }): Item {
+  const { id: _id, messageID: _messageID, sessionID: _sessionID, ...rest } = part
+  return rest
+}
+
+export function assign(part: Item): Item & { id: PartID } {
+  return {
+    ...part,
+    id: PartID.ascending(),
+  }
+}

packages/opencode/src/cli/cmd/tui/routes/session/dialog-fork-from-timeline.tsx

@@ -7,6 +7,7 @@ import { useSDK } from "@tui/context/sdk"
 import { useRoute } from "@tui/context/route"
 import { useDialog } from "../../ui/dialog"
 import type { PromptInfo } from "@tui/component/prompt/history"
+import { strip } from "@tui/component/prompt/part"
 
 export function DialogForkFromTimeline(props: { sessionID: string; onMove: (messageID: string) => void }) {
   const sync = useSync()
@@ -42,7 +43,7 @@ export function DialogForkFromTimeline(props: { sessionID: string; onMove: (mess
               if (part.type === "text") {
                 if (!part.synthetic) agg.input += part.text
               }
-              if (part.type === "file") agg.parts.push(part)
+              if (part.type === "file") agg.parts.push(strip(part))
               return agg
             },
             { input: "", parts: [] as PromptInfo["parts"] },

packages/opencode/src/cli/cmd/tui/routes/session/dialog-message.tsx

@@ -5,6 +5,7 @@ import { useSDK } from "@tui/context/sdk"
 import { useRoute } from "@tui/context/route"
 import { Clipboard } from "@tui/util/clipboard"
 import type { PromptInfo } from "@tui/component/prompt/history"
+import { strip } from "@tui/component/prompt/part"
 
 export function DialogMessage(props: {
   messageID: string
@@ -40,7 +41,7 @@ export function DialogMessage(props: {
                   if (part.type === "text") {
                     if (!part.synthetic) agg.input += part.text
                   }
-                  if (part.type === "file") agg.parts.push(part)
+                  if (part.type === "file") agg.parts.push(strip(part))
                   return agg
                 },
                 { input: "", parts: [] as PromptInfo["parts"] },

packages/opencode/src/provider/provider.ts

@@ -50,7 +50,8 @@ import { Installation } from "../installation"
 import { ModelID, ProviderID } from "./schema"
 import { JsonValue } from "@/util/json"
 
-const DEFAULT_CHUNK_TIMEOUT = 300_000
+// Chunk timeout disabled by default — prevents false timeouts on slow providers
+// (upstream #18264 by James Long). Enable via provider config chunkTimeout option.
 
 // Provider SDK layer: each AI SDK provider (OpenAI, Anthropic, Google, etc.) returns a unique type
 // with different methods (.responses, .chat, .languageModel). The BUNDLED_PROVIDERS dispatch table,
@@ -1187,7 +1188,7 @@ export namespace Provider {
       if (existing) return existing
 
       const customFetch = options["fetch"] as unknown as typeof globalThis.fetch | undefined
-      const chunkTimeout = (options["chunkTimeout"] as number) || DEFAULT_CHUNK_TIMEOUT
+      const chunkTimeout = options["chunkTimeout"] as number | undefined
       delete options["chunkTimeout"]
 
       // @ts-expect-error fetch function stored in JSON options object
@@ -1230,7 +1231,7 @@ export namespace Provider {
           timeout: false,
         })
 
-        if (!chunkAbortCtl) return res
+        if (!chunkAbortCtl || !chunkTimeout) return res
         return wrapSSE(res, chunkTimeout, chunkAbortCtl)
       }
 

packages/opencode/src/provider/transform.ts

@@ -759,11 +759,14 @@ export namespace ProviderTransform {
     }
 
     if (input.model.api.npm === "@ai-sdk/google" || input.model.api.npm === "@ai-sdk/google-vertex") {
-      result["thinkingConfig"] = {
-        includeThoughts: true,
-      }
-      if (input.model.api.id.includes("gemini-3")) {
-        result["thinkingConfig"]["thinkingLevel"] = "high"
+      // Only set thinkingConfig for models with reasoning capability (upstream #18283 by Protocol Zero)
+      if (input.model.capabilities.reasoning) {
+        result["thinkingConfig"] = {
+          includeThoughts: true,
+        }
+        if (input.model.api.id.includes("gemini-3")) {
+          result["thinkingConfig"]["thinkingLevel"] = "high"
+        }
       }
     }
 

packages/opencode/src/server/routes/global.ts

@@ -77,13 +77,33 @@ export const GlobalRoutes = lazy(() =>
               },
             }),
           })
-          async function handler(event: {
+          // Queue events to prevent backpressure when they arrive faster than
+          // the SSE stream can flush (upstream #18259 by James Long)
+          const queue: Array<{
+            directory?: string
+            payload: { type: string; properties: Record<string, string | number | boolean | null | object> }
+          }> = []
+          let flushing = false
+          async function flush() {
+            if (flushing) return
+            flushing = true
+            while (queue.length > 0) {
+              const event = queue.shift()!
+              try {
+                await stream.writeSSE({ data: JSON.stringify(event) })
+              } catch {
+                // Client disconnected — stop flushing
+                break
+              }
+            }
+            flushing = false
+          }
+          function handler(event: {
             directory?: string
             payload: { type: string; properties: Record<string, string | number | boolean | null | object> }
           }) {
-            await stream.writeSSE({
-              data: JSON.stringify(event),
-            })
+            queue.push(event)
+            flush()
           }
           GlobalBus.on("event", handler)
 

packages/opencode/src/session/message-v2.ts

@@ -1091,7 +1091,8 @@ export namespace MessageV2 {
           { cause: e },
         ).toObject()
       case e instanceof Error:
-        return new NamedError.Unknown({ message: e.toString() }, { cause: e }).toObject()
+        // Use e.message instead of e.toString() to preserve tagged error messages (upstream #18165 by Kit Langton)
+        return new NamedError.Unknown({ message: e.message }, { cause: e }).toObject()
       default:
         try {
           const parsed = ProviderError.parseStreamError(e)

packages/opencode/test/cli/cmd/tui/prompt-part.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, test } from "bun:test"
+import type { PromptInfo } from "../../../../src/cli/cmd/tui/component/prompt/history"
+import { assign, strip } from "../../../../src/cli/cmd/tui/component/prompt/part"
+
+describe("prompt part", () => {
+  test("strip removes persisted ids from reused file parts", () => {
+    const part = {
+      id: "prt_old",
+      sessionID: "ses_old",
+      messageID: "msg_old",
+      type: "file" as const,
+      mime: "image/png",
+      filename: "tiny.png",
+      url: "data:image/png;base64,abc",
+    }
+
+    expect(strip(part)).toEqual({
+      type: "file",
+      mime: "image/png",
+      filename: "tiny.png",
+      url: "data:image/png;base64,abc",
+    })
+  })
+
+  test("assign overwrites stale runtime ids", () => {
+    const part = {
+      id: "prt_old",
+      sessionID: "ses_old",
+      messageID: "msg_old",
+      type: "file" as const,
+      mime: "image/png",
+      filename: "tiny.png",
+      url: "data:image/png;base64,abc",
+    } as PromptInfo["parts"][number]
+
+    const next = assign(part)
+
+    expect(next.id).not.toBe("prt_old")
+    expect(next.id.startsWith("prt_")).toBe(true)
+    expect(next).toMatchObject({
+      type: "file",
+      mime: "image/png",
+      filename: "tiny.png",
+      url: "data:image/png;base64,abc",
+    })
+  })
+})