Show error if opencode fails to launch

packages/server/src/server/routes/workspaces.ts

@@ -35,10 +35,16 @@ export function registerWorkspaceRoutes(app: FastifyInstance, deps: RouteDeps) {
   })
 
   app.post("/api/workspaces", async (request, reply) => {
-    const body = WorkspaceCreateSchema.parse(request.body ?? {})
+    try {
-    const workspace = await deps.workspaceManager.create(body.path, body.name)
+      const body = WorkspaceCreateSchema.parse(request.body ?? {})
-    reply.code(201)
+      const workspace = await deps.workspaceManager.create(body.path, body.name)
-    return workspace
+      reply.code(201)
+      return workspace
+    } catch (error) {
+      request.log.error({ err: error }, "Failed to create workspace")
+      const message = error instanceof Error ? error.message : "Failed to create workspace"
+      reply.code(400).type("text/plain").send(message)
+    }
   })
 
   app.get<{ Params: { id: string } }>("/api/workspaces/:id", async (request, reply) => {

packages/server/src/workspaces/manager.ts

@@ -1,5 +1,6 @@
 import path from "path"
 import { spawnSync } from "child_process"
+import { connect } from "net"
 import { EventBus } from "../events/bus"
 import { ConfigStore } from "../config/store"
 import { BinaryRegistry } from "../config/binaries"
@@ -7,10 +8,12 @@ import { FileSystemBrowser } from "../filesystem/browser"
 import { searchWorkspaceFiles, WorkspaceFileSearchOptions } from "../filesystem/search"
 import { clearWorkspaceSearchCache } from "../filesystem/search-cache"
 import { WorkspaceDescriptor, WorkspaceFileResponse, FileSystemEntry } from "../api-types"
-import { WorkspaceRuntime } from "./runtime"
+import { WorkspaceRuntime, ProcessExitInfo } from "./runtime"
 import { Logger } from "../logger"
 import { getOpencodeConfigDir } from "../opencode-config"
 
+const STARTUP_STABILITY_DELAY_MS = 1500
+
 interface WorkspaceManagerOptions {
   rootDir: string
   configStore: ConfigStore
@@ -108,7 +111,7 @@ export class WorkspaceManager {
     }
 
     try {
-      const { pid, port } = await this.runtime.launch({
+      const { pid, port, exitPromise, getLastOutput } = await this.runtime.launch({
         workspaceId: id,
         folder: workspacePath,
         binaryPath: resolvedBinaryPath,
@@ -116,6 +119,8 @@ export class WorkspaceManager {
         onExit: (info) => this.handleProcessExit(info.workspaceId, info),
       })
 
+      await this.waitForWorkspaceReadiness({ workspaceId: id, port, exitPromise, getLastOutput })
+
       descriptor.pid = pid
       descriptor.port = port
       descriptor.status = "ready"
@@ -241,6 +246,159 @@ export class WorkspaceManager {
     return undefined
   }
 
+  private async waitForWorkspaceReadiness(params: {
+    workspaceId: string
+    port: number
+    exitPromise: Promise<ProcessExitInfo>
+    getLastOutput: () => string
+  }) {
+
+    await Promise.race([
+      this.waitForPortAvailability(params.port),
+      params.exitPromise.then((info) => {
+        throw this.buildStartupError(
+          params.workspaceId,
+          "exited before becoming ready",
+          info,
+          params.getLastOutput(),
+        )
+      }),
+    ])
+
+    await this.waitForInstanceHealth(params)
+
+    await Promise.race([
+      this.delay(STARTUP_STABILITY_DELAY_MS),
+      params.exitPromise.then((info) => {
+        throw this.buildStartupError(
+          params.workspaceId,
+          "exited shortly after start",
+          info,
+          params.getLastOutput(),
+        )
+      }),
+    ])
+  }
+
+  private async waitForInstanceHealth(params: {
+    workspaceId: string
+    port: number
+    exitPromise: Promise<ProcessExitInfo>
+    getLastOutput: () => string
+  }) {
+    const probeResult = await Promise.race([
+      this.probeInstance(params.workspaceId, params.port),
+      params.exitPromise.then((info) => {
+        throw this.buildStartupError(
+          params.workspaceId,
+          "exited during health checks",
+          info,
+          params.getLastOutput(),
+        )
+      }),
+    ])
+
+    if (probeResult.ok) {
+      return
+    }
+
+    const latestOutput = params.getLastOutput().trim()
+    const outputDetails = latestOutput ? ` Last output: ${latestOutput}` : ""
+    const reason = probeResult.reason ?? "Health check failed"
+    throw new Error(`Workspace ${params.workspaceId} failed health check: ${reason}.${outputDetails}`)
+  }
+
+  private async probeInstance(workspaceId: string, port: number): Promise<{ ok: boolean; reason?: string }> {
+    const url = `http://127.0.0.1:${port}/project/current`
+
+    try {
+      const response = await fetch(url)
+      if (!response.ok) {
+        const reason = `health probe returned HTTP ${response.status}`
+        this.options.logger.debug({ workspaceId, status: response.status }, "Health probe returned server error")
+        return { ok: false, reason }
+      }
+      return { ok: true }
+    } catch (error) {
+      const reason = error instanceof Error ? error.message : String(error)
+      this.options.logger.debug({ workspaceId, err: error }, "Health probe failed")
+      return { ok: false, reason }
+    }
+  }
+
+  private buildStartupError(
+    workspaceId: string,
+    phase: string,
+    exitInfo: ProcessExitInfo,
+    lastOutput: string,
+  ): Error {
+    const exitDetails = this.describeExit(exitInfo)
+    const trimmedOutput = lastOutput.trim()
+    const outputDetails = trimmedOutput ? ` Last output: ${trimmedOutput}` : ""
+    return new Error(`Workspace ${workspaceId} ${phase} (${exitDetails}).${outputDetails}`)
+  }
+
+  private waitForPortAvailability(port: number, timeoutMs = 5000): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const deadline = Date.now() + timeoutMs
+      let settled = false
+      let retryTimer: NodeJS.Timeout | null = null
+
+      const cleanup = () => {
+        settled = true
+        if (retryTimer) {
+          clearTimeout(retryTimer)
+          retryTimer = null
+        }
+      }
+
+      const tryConnect = () => {
+        if (settled) {
+          return
+        }
+        const socket = connect({ port, host: "127.0.0.1" }, () => {
+          cleanup()
+          socket.end()
+          resolve()
+        })
+        socket.once("error", () => {
+          socket.destroy()
+          if (settled) {
+            return
+          }
+          if (Date.now() >= deadline) {
+            cleanup()
+            reject(new Error(`Workspace port ${port} did not become ready within ${timeoutMs}ms`))
+          } else {
+            retryTimer = setTimeout(() => {
+              retryTimer = null
+              tryConnect()
+            }, 100)
+          }
+        })
+      }
+
+      tryConnect()
+    })
+  }
+
+  private delay(durationMs: number): Promise<void> {
+    if (durationMs <= 0) {
+      return Promise.resolve()
+    }
+    return new Promise((resolve) => setTimeout(resolve, durationMs))
+  }
+
+  private describeExit(info: ProcessExitInfo): string {
+    if (info.signal) {
+      return `signal ${info.signal}`
+    }
+    if (info.code !== null) {
+      return `code ${info.code}`
+    }
+    return "unknown reason"
+  }
+
   private handleProcessExit(workspaceId: string, info: { code: number | null; requested: boolean }) {
     const workspace = this.workspaces.get(workspaceId)
     if (!workspace) return

packages/server/src/workspaces/runtime.ts

@@ -13,7 +13,7 @@ interface LaunchOptions {
   onExit?: (info: ProcessExitInfo) => void
 }
 
-interface ProcessExitInfo {
+export interface ProcessExitInfo {
   workspaceId: string
   code: number | null
   signal: NodeJS.Signals | null
@@ -30,12 +30,18 @@ export class WorkspaceRuntime {
 
   constructor(private readonly eventBus: EventBus, private readonly logger: Logger) {}
 
-  async launch(options: LaunchOptions): Promise<{ pid: number; port: number }> {
+  async launch(options: LaunchOptions): Promise<{ pid: number; port: number; exitPromise: Promise<ProcessExitInfo>; getLastOutput: () => string }> {
     this.validateFolder(options.folder)
 
     const args = ["serve", "--port", "0", "--print-logs", "--log-level", "DEBUG"]
     const env = { ...process.env, ...(options.environment ?? {}) }
 
+    let exitResolve: ((info: ProcessExitInfo) => void) | null = null
+    const exitPromise = new Promise<ProcessExitInfo>((resolveExit) => {
+      exitResolve = resolveExit
+    })
+    let lastOutput = ""
+
     return new Promise((resolve, reject) => {
       this.logger.info(
         { workspaceId: options.workspaceId, folder: options.folder, binary: options.binaryPath },
@@ -83,11 +89,21 @@ export class WorkspaceRuntime {
         cleanupStreams()
         child.removeListener("error", handleError)
         child.removeListener("exit", handleExit)
+        const exitInfo: ProcessExitInfo = {
+          workspaceId: options.workspaceId,
+          code,
+          signal,
+          requested: managed.requestedStop,
+        }
+        if (exitResolve) {
+          exitResolve(exitInfo)
+          exitResolve = null
+        }
         if (!portFound) {
           const reason = stderrBuffer || `Process exited with code ${code}`
           reject(new Error(reason))
         } else {
-          options.onExit?.({ workspaceId: options.workspaceId, code, signal, requested: managed.requestedStop })
+          options.onExit?.(exitInfo)
         }
       }
 
@@ -96,6 +112,10 @@ export class WorkspaceRuntime {
         child.removeListener("exit", handleExit)
         this.processes.delete(options.workspaceId)
         this.logger.error({ workspaceId: options.workspaceId, err: error }, "Workspace runtime error")
+        if (exitResolve) {
+          exitResolve({ workspaceId: options.workspaceId, code: null, signal: null, requested: managed.requestedStop })
+          exitResolve = null
+        }
         reject(error)
       }
 
@@ -109,18 +129,20 @@ export class WorkspaceRuntime {
         stdoutBuffer = lines.pop() ?? ""
 
         for (const line of lines) {
-          if (!line.trim()) continue
+          const trimmed = line.trim()
+          if (!trimmed) continue
+          lastOutput = trimmed
           this.emitLog(options.workspaceId, "info", line)
 
           if (!portFound) {
             const portMatch = line.match(/opencode server listening on http:\/\/.+:(\d+)/i)
             if (portMatch) {
               portFound = true
-              cleanupStreams()
               child.removeListener("error", handleError)
               const port = parseInt(portMatch[1], 10)
               this.logger.info({ workspaceId: options.workspaceId, port }, "Workspace runtime allocated port")
-              resolve({ pid: child.pid!, port })
+              const getLastOutput = () => lastOutput.trim()
+              resolve({ pid: child.pid!, port, exitPromise, getLastOutput })
             }
           }
         }
@@ -133,7 +155,9 @@ export class WorkspaceRuntime {
         stderrBuffer = lines.pop() ?? ""
 
         for (const line of lines) {
-          if (!line.trim()) continue
+          const trimmed = line.trim()
+          if (!trimmed) continue
+          lastOutput = `[stderr] ${trimmed}`
           this.emitLog(options.workspaceId, "error", line)
         }
       })

packages/ui/src/App.tsx

@@ -21,11 +21,9 @@ import {
   hasInstances,
   isSelectingFolder,
   setIsSelectingFolder,
-  setHasInstances,
   showFolderSelection,
   setShowFolderSelection,
 } from "./stores/ui"
-import { instances as instanceStore } from "./stores/instances"
 import { useConfig } from "./stores/preferences"
 import {
   createInstance,
@@ -65,7 +63,12 @@ const App: Component = () => {
     setThinkingBlocksExpansion,
   } = useConfig()
   const [escapeInDebounce, setEscapeInDebounce] = createSignal(false)
-  const [launchErrorBinary, setLaunchErrorBinary] = createSignal<string | null>(null)
+  interface LaunchErrorState {
+    message: string
+    binaryPath: string
+    missingBinary: boolean
+  }
+  const [launchError, setLaunchError] = createSignal<LaunchErrorState | null>(null)
   const [isAdvancedSettingsOpen, setIsAdvancedSettingsOpen] = createSignal(false)
   const [remoteAccessOpen, setRemoteAccessOpen] = createSignal(false)
   const [instanceTabBarHeight, setInstanceTabBarHeight] = createSignal(0)
@@ -105,14 +108,30 @@ const App: Component = () => {
   })
 
   const launchErrorPath = () => {
-    const value = launchErrorBinary()
+    const value = launchError()?.binaryPath
     if (!value) return "opencode"
     return value.trim() || "opencode"
   }
 
-  const isMissingBinaryError = (error: unknown): boolean => {
+  const launchErrorMessage = () => launchError()?.message ?? ""
-    if (!error) return false
+
-    const message = typeof error === "string" ? error : error instanceof Error ? error.message : String(error)
+  const formatLaunchErrorMessage = (error: unknown): string => {
+    if (!error) {
+      return "Failed to launch workspace"
+    }
+    const raw = typeof error === "string" ? error : error instanceof Error ? error.message : String(error)
+    try {
+      const parsed = JSON.parse(raw)
+      if (parsed && typeof parsed.error === "string") {
+        return parsed.error
+      }
+    } catch {
+      // ignore JSON parse errors
+    }
+    return raw
+  }
+
+  const isMissingBinaryMessage = (message: string): boolean => {
     const normalized = message.toLowerCase()
     return (
       normalized.includes("opencode binary not found") ||
@@ -123,7 +142,7 @@ const App: Component = () => {
     )
   }
 
-  const clearLaunchError = () => setLaunchErrorBinary(null)
+  const clearLaunchError = () => setLaunchError(null)
 
   async function handleSelectFolder(folderPath: string, binaryPath?: string) {
     if (!folderPath) {
@@ -135,7 +154,6 @@ const App: Component = () => {
       recordWorkspaceLaunch(folderPath, selectedBinary)
       clearLaunchError()
       const instanceId = await createInstance(folderPath, selectedBinary)
-      setHasInstances(true)
       setShowFolderSelection(false)
       setIsAdvancedSettingsOpen(false)
 
@@ -144,10 +162,13 @@ const App: Component = () => {
         port: instances().get(instanceId)?.port,
       })
     } catch (error) {
-      clearLaunchError()
+      const message = formatLaunchErrorMessage(error)
-      if (isMissingBinaryError(error)) {
+      const missingBinary = isMissingBinaryMessage(message)
-        setLaunchErrorBinary(selectedBinary)
+      setLaunchError({
-      }
+        message,
+        binaryPath: selectedBinary,
+        missingBinary,
+      })
       log.error("Failed to create instance", error)
     } finally {
       setIsSelectingFolder(false)
@@ -191,9 +212,6 @@ const App: Component = () => {
     if (!confirmed) return
 
     await stopInstance(instanceId)
-    if (instances().size === 0) {
-      setHasInstances(false)
-    }
   }
 
   async function handleNewSession(instanceId: string) {
@@ -304,7 +322,7 @@ const App: Component = () => {
         onClose={handleDisconnectedInstanceClose}
       />
 
-      <Dialog open={Boolean(launchErrorBinary())} modal>
+      <Dialog open={Boolean(launchError())} modal>
         <Dialog.Portal>
           <Dialog.Overlay class="modal-overlay" />
           <div class="fixed inset-0 z-50 flex items-center justify-center p-4">
@@ -312,8 +330,8 @@ const App: Component = () => {
               <div>
                 <Dialog.Title class="text-xl font-semibold text-primary">Unable to launch OpenCode</Dialog.Title>
                 <Dialog.Description class="text-sm text-secondary mt-2 break-words">
-                  Install the OpenCode CLI and make sure it is available in your PATH, or pick a custom binary from
+                  We couldn't start the selected OpenCode binary. Review the error output below or choose a different
-                  Advanced Settings.
+                  binary from Advanced Settings.
                 </Dialog.Description>
               </div>
 
@@ -322,10 +340,23 @@ const App: Component = () => {
                 <p class="text-sm font-mono text-primary break-all">{launchErrorPath()}</p>
               </div>
 
+              <Show when={launchErrorMessage()}>
+                <div class="rounded-lg border border-base bg-surface-secondary p-4">
+                  <p class="text-xs font-medium text-muted uppercase tracking-wide mb-1">Error output</p>
+                  <pre class="text-sm font-mono text-primary whitespace-pre-wrap break-words max-h-48 overflow-y-auto">{launchErrorMessage()}</pre>
+                </div>
+              </Show>
+
               <div class="flex justify-end gap-2">
-                <button type="button" class="selector-button selector-button-secondary" onClick={handleLaunchErrorAdvanced}>
+                <Show when={launchError()?.missingBinary}>
-                  Open Advanced Settings
+                  <button
-                </button>
+                    type="button"
+                    class="selector-button selector-button-secondary"
+                    onClick={handleLaunchErrorAdvanced}
+                  >
+                    Open Advanced Settings
+                  </button>
+                </Show>
                 <button type="button" class="selector-button selector-button-primary" onClick={handleLaunchErrorClose}>
                   Close
                 </button>

packages/ui/src/stores/instances.ts

@@ -34,6 +34,11 @@ const [logStreamingState, setLogStreamingState] = createSignal<Map<string, boole
 const [permissionQueues, setPermissionQueues] = createSignal<Map<string, Permission[]>>(new Map())
 const [activePermissionId, setActivePermissionId] = createSignal<Map<string, string | null>>(new Map())
 const permissionSessionCounts = new Map<string, Map<string, number>>()
+
+function syncHasInstancesFlag() {
+  const readyExists = Array.from(instances().values()).some((instance) => instance.status === "ready")
+  setHasInstances(readyExists)
+}
 interface DisconnectedInstanceInfo {
   id: string
   folder: string
@@ -68,7 +73,6 @@ function upsertWorkspace(descriptor: WorkspaceDescriptor) {
     updateInstance(descriptor.id, mapped)
   } else {
     addInstance(mapped)
-    setHasInstances(true)
   }
 
   if (descriptor.status === "ready") {
@@ -135,9 +139,6 @@ void (async function initializeWorkspaces() {
   try {
     const workspaces = await serverApi.fetchWorkspaces()
     workspaces.forEach((workspace) => upsertWorkspace(workspace))
-    if (workspaces.length === 0) {
-      setHasInstances(false)
-    }
   } catch (error) {
     log.error("Failed to load workspaces", error)
   }
@@ -159,9 +160,6 @@ function handleWorkspaceEvent(event: WorkspaceEventPayload) {
     case "workspace.stopped":
       releaseInstanceResources(event.workspaceId)
       removeInstance(event.workspaceId)
-      if (instances().size === 0) {
-        setHasInstances(false)
-      }
       break
     case "workspace.log":
       handleWorkspaceLog(event.entry)
@@ -249,6 +247,7 @@ function addInstance(instance: Instance) {
   })
   ensureLogContainer(instance.id)
   ensureLogStreamingState(instance.id)
+  syncHasInstancesFlag()
 }
 
 function updateInstance(id: string, updates: Partial<Instance>) {
@@ -260,6 +259,7 @@ function updateInstance(id: string, updates: Partial<Instance>) {
     }
     return next
   })
+  syncHasInstancesFlag()
 }
 
 function removeInstance(id: string) {
@@ -301,6 +301,7 @@ function removeInstance(id: string) {
   clearCacheForInstance(id)
   messageStoreBus.unregisterInstance(id)
   clearInstanceDraftPrompts(id)
+  syncHasInstancesFlag()
 }
 
 async function createInstance(folder: string, _binaryPath?: string): Promise<string> {
@@ -328,9 +329,6 @@ async function stopInstance(id: string) {
   }
 
   removeInstance(id)
-  if (instances().size === 0) {
-    setHasInstances(false)
-  }
 }
 
 async function fetchLspStatus(instanceId: string): Promise<LspStatus[] | undefined> {
@@ -590,9 +588,6 @@ async function acknowledgeDisconnectedInstance(): Promise<void> {
     log.error("Failed to stop disconnected instance", error)
   } finally {
     setDisconnectedInstance(null)
-    if (instances().size === 0) {
-      setHasInstances(false)
-    }
   }
 }