fix: permanently resolve agent name duplication yo-yo bug

src/hooks/atlas/boulder-continuation-injector.test.ts

@@ -0,0 +1,54 @@
+import { describe, test, expect, beforeEach, afterEach, mock } from "bun:test"
+import type { PluginInput } from "@opencode-ai/plugin"
+import { registerAgentName, _resetForTesting } from "../../features/claude-code-session-state"
+import { injectBoulderContinuation } from "./boulder-continuation-injector"
+
+describe("injectBoulderContinuation", () => {
+  beforeEach(() => {
+    // given
+    _resetForTesting()
+  })
+
+  afterEach(() => {
+    // then
+    _resetForTesting()
+  })
+
+  test("normalizes config-key agent to display-name for promptAsync", async () => {
+    // given
+    registerAgentName("atlas")
+    const promptAsyncMock = mock(async (_request: unknown) => undefined)
+    const messagesMock = mock(async () => ({ data: [] }))
+
+    const ctx = {
+      directory: "/tmp",
+      client: {
+        session: {
+          messages: messagesMock,
+          promptAsync: promptAsyncMock,
+        },
+      },
+    } as unknown as PluginInput
+
+    // when
+    await injectBoulderContinuation({
+      ctx,
+      sessionID: "ses_test_123",
+      planName: "test-plan",
+      remaining: 1,
+      total: 2,
+      agent: "atlas",
+      sessionState: { promptFailureCount: 0 },
+    })
+
+    // then
+    expect(promptAsyncMock).toHaveBeenCalledTimes(1)
+    expect(promptAsyncMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        body: expect.objectContaining({
+          agent: "Atlas (Plan Executor)",
+        }),
+      }),
+    )
+  })
+})

src/hooks/atlas/boulder-continuation-injector.ts

@@ -1,9 +1,9 @@
 import type { PluginInput } from "@opencode-ai/plugin"
 import type { BackgroundManager } from "../../features/background-agent"
 import { isAgentRegistered } from "../../features/claude-code-session-state"
+import { normalizeAgentForPrompt } from "../../shared/agent-display-names"
 import { log } from "../../shared/logger"
 import { createInternalAgentTextPart, resolveInheritedPromptTools } from "../../shared"
-import { getAgentConfigKey } from "../../shared/agent-display-names"
 import { HOOK_NAME } from "./hook-name"
 import { BOULDER_CONTINUATION_PROMPT } from "./system-reminder-templates"
 import { resolveRecentPromptContextForSession } from "./recent-model-resolver"
@@ -73,7 +73,7 @@ export async function injectBoulderContinuation(input: {
 		await ctx.client.session.promptAsync({
 			path: { id: sessionID },
 			body: {
-				agent: getAgentConfigKey(continuationAgent),
+				agent: normalizeAgentForPrompt(continuationAgent) ?? continuationAgent,
 				...(promptContext.model !== undefined ? { model: promptContext.model } : {}),
 				...(inheritedTools ? { tools: inheritedTools } : {}),
         parts: [createInternalAgentTextPart(prompt)],

src/hooks/atlas/index.test.ts

@@ -1679,9 +1679,42 @@ session_id: ses_untrusted_999
        // then - should call prompt for sisyphus
        expect(mockInput._promptMock).toHaveBeenCalled()
        const callArgs = mockInput._promptMock.mock.calls[0][0]
-       expect(callArgs.body.agent).toBe("sisyphus")
+       expect(callArgs.body.agent).toBe("Sisyphus (Ultraworker)")
      })
 
+    test("should preserve display-name agent in continuation prompt when boulder agent uses display form", async () => {
+      // given - boulder state uses display-form agent name
+      const planPath = join(TEST_DIR, "test-plan.md")
+      writeFileSync(planPath, "# Plan\n- [ ] Task 1\n- [ ] Task 2")
+
+      const state: BoulderState = {
+        active_plan: planPath,
+        started_at: "2026-01-02T10:00:00Z",
+        session_ids: [MAIN_SESSION_ID],
+        plan_name: "test-plan",
+        agent: "Atlas (Plan Executor)",
+      }
+      writeBoulderState(TEST_DIR, state)
+      registerAgentName("Atlas (Plan Executor)")
+
+      const mockInput = createMockPluginInput()
+      const hook = createAtlasHook(mockInput)
+
+      // when
+      await hook.handler({
+        event: {
+          type: "session.idle",
+          properties: { sessionID: MAIN_SESSION_ID },
+        },
+      })
+
+      // then
+      expect(mockInput._promptMock).toHaveBeenCalled()
+      const callArgs = mockInput._promptMock.mock.calls[0][0]
+      expect(callArgs.body.agent).toBe("Atlas (Plan Executor)")
+      expect(callArgs.body.agent).not.toBe("atlas")
+    })
+
     test("should debounce rapid continuation injections (prevent infinite loop)", async () => {
       // given - boulder state with incomplete plan
       const planPath = join(TEST_DIR, "test-plan.md")