diff --git a/src/ida/IdaBusyHealth.test.ts b/src/ida/IdaBusyHealth.test.ts
index 8b99bf9d55..e4671e1850 100644
--- a/src/ida/IdaBusyHealth.test.ts
+++ b/src/ida/IdaBusyHealth.test.ts
@@ -1,4 +1,5 @@
 import { expect, it } from "vitest";
+import { AnalysisTimeoutError } from "../domain/analysisErrorCore.js";
 import type { JsonValue } from "../domain/jsonValue.js";
 import type { IdaMcpConnection } from "./IdaMcpConnection.js";
 import { readSettledHealth } from "./IdaBusyHealth.js";
@@ -139,8 +140,13 @@ it("reports the busy tool of the last observation", async () => {
     clock,
   }).catch((cause: unknown) => cause);
 
-  expect(failure, "the operation names the tool seen last").toMatchObject({
-    operation: "server_health: headless worker still busy in last_tool",
+  expect(
+    failure,
+    "the producer retains the tool seen last independently of attribution",
+  ).toMatchObject({
+    operation: "server_health",
+    userMessage: expect.stringContaining("last_tool"),
+    diagnostics: { busy_tool: "last_tool" },
     cause: busy("last_tool"),
   });
 });
@@ -166,3 +172,34 @@ it("rejects without another read when the signal aborts after the pause has fulf
   });
   expect(failure instanceof Error && failure.cause).toBe(reason);
 });
+
+it("retains the last busy observation when a shortened health request times out", async () => {
+  const capturedOutput = {
+    stdout: "",
+    stderr: "transport closed",
+    truncated: false,
+  };
+  const raw = busy("last_tool");
+  let reads = 0;
+  const { connection } = scripted([raw]);
+  connection.call = async (_name, _args, options) => {
+    if (reads++ === 0) return raw;
+    throw new AnalysisTimeoutError("server_health", options?.timeoutMs ?? 0, {
+      capturedOutput,
+    });
+  };
+  const { clock } = virtualClock();
+  const failure = await readSettledHealth(connection, {
+    database: "db",
+    timeoutMs: 350,
+    clock,
+  }).catch((cause: unknown) => cause);
+  expect(failure).toMatchObject({
+    operation: "server_health",
+    timeoutMs: 350,
+    cause: raw,
+    capturedOutput,
+    userMessage: expect.stringContaining("last_tool"),
+    diagnostics: { busy_tool: "last_tool", health_request_timeout_ms: 250 },
+  });
+});
diff --git a/src/ida/IdaBusyHealth.ts b/src/ida/IdaBusyHealth.ts
index c68f8d4b85..55ffc58958 100644
--- a/src/ida/IdaBusyHealth.ts
+++ b/src/ida/IdaBusyHealth.ts
@@ -35,7 +35,7 @@ const isBusyStatus = (raw: JsonValue): boolean =>
 
 interface LastBusyHealth {
   readonly raw: JsonValue;
-  readonly operation: string;
+  readonly tool: string;
 }
 
 /**
@@ -90,15 +90,7 @@ export const readSettledHealth = async (
         cause.timeoutMs === requestTimeoutMs &&
         requestTimeoutMs < timeoutMs
       ) {
-        throw new AnalysisTimeoutError(lastBusy.operation, timeoutMs, {
-          cause: lastBusy.raw,
-          capturedOutput: cause.capturedOutput,
-          ...idaRegistrationTimeoutGuidance(timeoutMs, "readiness"),
-          diagnostics: {
-            health_request_operation: cause.operation,
-            health_request_timeout_ms: cause.timeoutMs,
-          },
-        });
+        throw busyTimeout(lastBusy, timeoutMs, cause);
       }
       throw cause;
     }
@@ -109,7 +101,7 @@ export const readSettledHealth = async (
     }
     const observedBusy = {
       raw,
-      operation: `server_health: headless worker still busy in ${busyToolName(busy.data.busy_tool)}`,
+      tool: busyToolName(busy.data.busy_tool),
     };
     lastBusy = observedBusy;
     const expired = (): AnalysisTimeoutError =>
@@ -139,8 +131,24 @@ export const readSettledHealth = async (
 const busyTimeout = (
   lastBusy: LastBusyHealth,
   timeoutMs: number,
-): AnalysisTimeoutError =>
-  new AnalysisTimeoutError(lastBusy.operation, timeoutMs, {
+  requestFailure?: AnalysisTimeoutError,
+): AnalysisTimeoutError => {
+  const guidance = idaRegistrationTimeoutGuidance(timeoutMs, "readiness");
+  return new AnalysisTimeoutError("server_health", timeoutMs, {
     cause: lastBusy.raw,
-    ...idaRegistrationTimeoutGuidance(timeoutMs, "readiness"),
+    ...guidance,
+    userMessage: `${guidance.userMessage} The last reported busy tool was ${lastBusy.tool}.`,
+    diagnostics: {
+      busy_tool: lastBusy.tool,
+      ...(requestFailure === undefined
+        ? {}
+        : {
+            health_request_operation: requestFailure.operation,
+            health_request_timeout_ms: requestFailure.timeoutMs,
+          }),
+    },
+    ...(requestFailure === undefined
+      ? {}
+      : { capturedOutput: requestFailure.capturedOutput }),
   });
+};
diff --git a/src/ida/IdaSessionClient.test.ts b/src/ida/IdaSessionClient.test.ts
index 15afaa203a..a7d24f9ac6 100644
--- a/src/ida/IdaSessionClient.test.ts
+++ b/src/ida/IdaSessionClient.test.ts
@@ -771,22 +771,28 @@ describe("headless IDA transient busy health", () => {
     expect(projected.retryable, "the caller may retry").toBe(true);
     expect(
       projected.details,
-      "the observed busy tool is named exactly in the operation",
+      "the timeout is attributed to the requested operation",
     ).toMatchObject({
-      operation: "server_health: headless worker still busy in config_json_get",
+      operation: "health",
       timeout_ms: 300,
     });
     expect(
-      result.error.message,
-      "the error message names the busy tool",
+      projected.message,
+      "the public error message names the busy tool",
     ).toContain("config_json_get");
     expect(
       `${result.error.message} ${projected.message}`,
       "no Hopper wording leaks in",
     ).not.toContain("Hopper");
-    expect(result.error.cause, "the raw busy payload is the cause").toEqual(
-      busy,
-    );
+    expect(
+      result.error.cause,
+      "reattribution preserves the producing timeout",
+    ).toMatchObject({
+      _tag: "AnalysisTimeoutError",
+      operation: "server_health",
+      cause: busy,
+      diagnostics: { busy_tool: "config_json_get" },
+    });
     expect(
       elapsed,
       "the wait runs to the deadline, not less",
@@ -808,10 +814,14 @@ describe("headless IDA transient busy health", () => {
     if (result.ok) throw new Error("expected a busy timeout");
     expect(
       projectAnalysisError(result.error).details,
-      "an omitted busy_tool is reported as exactly unknown",
+      "the public operation stays independent of an omitted busy tool",
     ).toMatchObject({
-      operation: "server_health: headless worker still busy in unknown",
+      operation: "health",
     });
+    expect(result.error.diagnostics).toMatchObject({ busy_tool: "unknown" });
+    expect(projectAnalysisError(result.error).message).toContain(
+      "busy tool was unknown",
+    );
     await expectCleanClose(producer, client);
   });
 
@@ -832,11 +842,12 @@ describe("headless IDA transient busy health", () => {
         projectAnalysisError(result.error).details,
         "only a tool-name-shaped value is repeated",
       ).toMatchObject({
-        operation: "server_health: headless worker still busy in unknown",
+        operation: "health",
       });
+      expect(result.error.diagnostics).toMatchObject({ busy_tool: "unknown" });
       expect(
-        result.error.message,
-        "the producer text never reaches the error message",
+        projectAnalysisError(result.error).message,
+        "the producer text never reaches the public error message",
       ).not.toContain(tool);
       await expectCleanClose(producer, client);
     },