perf(runtime): cache unchanged prompt verification tail

src/main/runtime/agent-prompt-submission-verification.test.ts

@@ -4,6 +4,7 @@ import {
   AGENT_PROMPT_HOOK_EFFECT_TIMEOUT_MS,
   type AgentPromptActivity,
   isAgentPromptStalledError,
+  readAgentPromptWaitText,
   resolveAgentPromptEffectTimeoutMs,
   verifyAgentPromptSubmission
 } from './agent-prompt-submission-verification'
@@ -23,6 +24,17 @@ function activity(overrides: Partial<AgentPromptActivity> = {}): AgentPromptActi
 describe('agent prompt submission verification', () => {
   afterEach(() => vi.useRealTimers())
 
+  it('reuses wait text while the PTY output sequence is unchanged', () => {
+    const cache: { outputSequence?: number; waitText?: string } = {}
+    const readWaitText = vi.fn(() => 'retained terminal tail')
+
+    expect(readAgentPromptWaitText(cache, 7, readWaitText)).toBe('retained terminal tail')
+    expect(readAgentPromptWaitText(cache, 7, readWaitText)).toBe('retained terminal tail')
+    expect(readAgentPromptWaitText(cache, 8, readWaitText)).toBe('retained terminal tail')
+
+    expect(readWaitText).toHaveBeenCalledTimes(2)
+  })
+
   it('accepts an observed working transition', async () => {
     vi.useFakeTimers()
     let current = activity()

src/main/runtime/agent-prompt-submission-verification.ts

@@ -22,6 +22,11 @@ export type AgentPromptActivity = Readonly<{
   status: 'working' | 'permission' | 'idle' | null
 }>
 
+export type AgentPromptWaitTextCache = {
+  outputSequence?: number
+  waitText?: string
+}
+
 type AgentPromptVerificationOptions = {
   baseline: AgentPromptActivity
   readActivity: () => AgentPromptActivity
@@ -47,6 +52,20 @@ export function isAgentPromptStalledError(error: unknown): boolean {
   )
 }
 
+export function readAgentPromptWaitText(
+  cache: AgentPromptWaitTextCache,
+  outputSequence: number,
+  readWaitText: () => string
+): string {
+  if (cache.outputSequence === outputSequence && cache.waitText !== undefined) {
+    return cache.waitText
+  }
+  const waitText = readWaitText()
+  cache.outputSequence = outputSequence
+  cache.waitText = waitText
+  return waitText
+}
+
 export async function verifyAgentPromptSubmission(
   options: AgentPromptVerificationOptions
 ): Promise<void> {

src/main/runtime/orca-runtime.ts

@@ -106,6 +106,8 @@ import {
 } from '../../shared/agent-prompt-injection'
 import {
   type AgentPromptActivity,
+  type AgentPromptWaitTextCache,
+  readAgentPromptWaitText,
   resolveAgentPromptEffectTimeoutMs,
   verifyAgentPromptSubmission
 } from './agent-prompt-submission-verification'
@@ -19366,7 +19368,8 @@ export class OrcaRuntimeService {
 
   private getTerminalAgentStatusSnapshot(
     handle: string,
-    expectedPtyId: string
+    expectedPtyId: string,
+    waitTextOverride?: string
   ): TerminalAgentStatusSnapshot {
     const pty = this.getLivePtyForHandle(handle)
     if (pty) {
@@ -19386,11 +19389,9 @@ export class OrcaRuntimeService {
           { title: pty.pty.title, updatedAt: pty.pty.titleUpdatedAt },
           { title: pty.pty.lastOscTitle, updatedAt: pty.pty.lastOscTitleAt }
         )
-      const waitText = buildTerminalWaitText(
-        pty.pty.tailBuffer,
-        pty.pty.tailPartialLine,
-        pty.pty.preview
-      )
+      const waitText =
+        waitTextOverride ??
+        buildTerminalWaitText(pty.pty.tailBuffer, pty.pty.tailPartialLine, pty.pty.preview)
       return {
         waitText,
         waitBlockedAt: pty.pty.waitBlockedAt,
@@ -19418,7 +19419,9 @@ export class OrcaRuntimeService {
       { title: this.tabs.get(leaf.tabId)?.title, updatedAt: 0 }
     )
     return {
-      waitText: buildTerminalWaitText(leaf.tailBuffer, leaf.tailPartialLine, leaf.preview),
+      waitText:
+        waitTextOverride ??
+        buildTerminalWaitText(leaf.tailBuffer, leaf.tailPartialLine, leaf.preview),
       waitBlockedAt: leaf.waitBlockedAt,
       title: title?.title ?? null,
       titleStatus: title ? detectAgentStatusFromTitle(title.title) : leaf.lastAgentStatus,
@@ -20077,7 +20080,8 @@ export class OrcaRuntimeService {
     }
     assertAgentPromptRequestActive(options.signal)
     this.assertAgentPromptGeneration(ptyId, generation)
-    const baseline = this.getAgentPromptActivity(handle, ptyId)
+    const waitTextCache: AgentPromptWaitTextCache = {}
+    const baseline = this.getAgentPromptActivity(handle, ptyId, waitTextCache)
     this.assertAgentPromptPermissionSafe(permissionBaseline, baseline)
     const suffixWrote = this.ptyController?.write(ptyId, AGENT_PROMPT_SUBMIT) ?? false
     if (!suffixWrote) {
@@ -20085,7 +20089,7 @@ export class OrcaRuntimeService {
     }
     await verifyAgentPromptSubmission({
       baseline,
-      readActivity: () => this.getAgentPromptActivity(handle, ptyId),
+      readActivity: () => this.getAgentPromptActivity(handle, ptyId, waitTextCache),
       timeoutMs: resolveAgentPromptEffectTimeoutMs(this.getPtyAgent(ptyId)),
       signal: options.signal
     })
@@ -20114,8 +20118,13 @@ export class OrcaRuntimeService {
     }
   }
 
-  private getAgentPromptActivity(handle: string, ptyId: string): AgentPromptActivity {
+  private getAgentPromptActivity(
+    handle: string,
+    ptyId: string,
+    waitTextCache?: AgentPromptWaitTextCache
+  ): AgentPromptActivity {
     this.assertLiveTerminalHandleTargetsPty(handle, ptyId)
+    const outputSequence = this.getPtyOutputSequence(ptyId)
     const explicitCandidate = this.getFreshExplicitAgentStatusForHandle(handle)
     const explicitFloor = this.agentPromptExplicitStatusFloorByPtyId.get(ptyId)
     const explicit =
@@ -20133,7 +20142,14 @@ export class OrcaRuntimeService {
       (!explicit ||
         lifecycle.updatedAt > explicit.updatedAt ||
         (lifecycle.updatedAt === explicit.updatedAt && lifecycle.status === 'permission'))
-    const terminal = this.getTerminalAgentStatusSnapshot(handle, ptyId)
+    const waitText = waitTextCache
+      ? readAgentPromptWaitText(
+          waitTextCache,
+          outputSequence,
+          () => this.getTerminalAgentStatusSnapshot(handle, ptyId).waitText
+        )
+      : undefined
+    const terminal = this.getTerminalAgentStatusSnapshot(handle, ptyId, waitText)
     const status = this.hasAuthoritativeTerminalWaitPermission(terminal, explicit, lifecycle)
       ? 'permission'
       : lifecycleIsNewer
@@ -20148,7 +20164,7 @@ export class OrcaRuntimeService {
       // stateStartedAt, not updatedAt — same-state tool/prompt pings refresh updatedAt and would
       // otherwise pass off an in-progress turn as a new one.
       explicitWorkingStartedAt: explicit?.status === 'working' ? explicit.stateStartedAt : null,
-      outputSequence: this.getPtyOutputSequence(ptyId),
+      outputSequence,
       status
     }
   }