fix: image reading error, also add error toast for event bus

packages/opencode/src/cli/cmd/tui/app.tsx

@@ -367,6 +367,27 @@ function App() {
     }
   })
 
+  event.on(SessionApi.Event.Error.type, (evt) => {
+    const error = evt.properties.error
+    const message = (() => {
+      if (!error) return "An error occured"
+
+      if (typeof error === "object") {
+        const data = error.data
+        if ("message" in data && typeof data.message === "string") {
+          return data.message
+        }
+      }
+      return String(error)
+    })()
+
+    toast.show({
+      variant: "error",
+      message,
+      duration: 5000,
+    })
+  })
+
   return (
     <box
       width={dimensions().width}

packages/opencode/src/session/prompt.ts

@@ -51,6 +51,7 @@ import { $, fileURLToPath } from "bun"
 import { ConfigMarkdown } from "../config/markdown"
 import { SessionSummary } from "./summary"
 import { Config } from "@/config/config"
+import { NamedError } from "@/util/error"
 
 export namespace SessionPrompt {
   const log = Log.create({ service: "session.prompt" })
@@ -735,17 +736,8 @@ export namespace SessionPrompt {
                   }
                 }
                 const args = { filePath: filepath, offset, limit }
-                const result = await ReadTool.init().then((t) =>
-                  t.execute(args, {
-                    sessionID: input.sessionID,
-                    abort: new AbortController().signal,
-                    agent: input.agent!,
-                    messageID: info.id,
-                    extra: { bypassCwdCheck: true },
-                    metadata: async () => {},
-                  }),
-                )
-                return [
+
+                const pieces: MessageV2.Part[] = [
                   {
                     id: Identifier.ascending("part"),
                     messageID: info.id,
@@ -754,21 +746,55 @@ export namespace SessionPrompt {
                     synthetic: true,
                     text: `Called the Read tool with the following input: ${JSON.stringify(args)}`,
                   },
-                  {
-                    id: Identifier.ascending("part"),
-                    messageID: info.id,
-                    sessionID: input.sessionID,
-                    type: "text",
-                    synthetic: true,
-                    text: result.output,
-                  },
-                  {
-                    ...part,
-                    id: part.id ?? Identifier.ascending("part"),
-                    messageID: info.id,
-                    sessionID: input.sessionID,
-                  },
                 ]
+
+                await ReadTool.init()
+                  .then(async (t) => {
+                    const result = await t.execute(args, {
+                      sessionID: input.sessionID,
+                      abort: new AbortController().signal,
+                      agent: input.agent!,
+                      messageID: info.id,
+                      extra: { bypassCwdCheck: true },
+                      metadata: async () => {},
+                    })
+                    pieces.push(
+                      {
+                        id: Identifier.ascending("part"),
+                        messageID: info.id,
+                        sessionID: input.sessionID,
+                        type: "text",
+                        synthetic: true,
+                        text: result.output,
+                      },
+                      {
+                        ...part,
+                        id: part.id ?? Identifier.ascending("part"),
+                        messageID: info.id,
+                        sessionID: input.sessionID,
+                      },
+                    )
+                  })
+                  .catch((error) => {
+                    log.error("failed to read file", { error })
+                    const message = error instanceof Error ? error.message : error.toString()
+                    Bus.publish(Session.Event.Error, {
+                      sessionID: input.sessionID,
+                      error: new NamedError.Unknown({
+                        message,
+                      }).toObject(),
+                    })
+                    pieces.push({
+                      id: Identifier.ascending("part"),
+                      messageID: info.id,
+                      sessionID: input.sessionID,
+                      type: "text",
+                      synthetic: true,
+                      text: `Read tool failed to read ${filepath} with the following error: ${message}`,
+                    })
+                  })
+
+                return pieces
               }
 
               if (part.mime === "application/x-directory") {