fix(core): separate interruption from finish

packages/client/src/generated/types.ts

@@ -572,6 +572,7 @@ export type SessionsContextOutput = {
         >
         readonly snapshot?: { readonly start?: string; readonly end?: string; readonly files?: ReadonlyArray<string> }
         readonly finish?: string
+        readonly settlement?: "completed" | "failed" | "interrupted"
         readonly cost?: number
         readonly tokens?: {
           readonly input: number
@@ -795,6 +796,14 @@ export type SessionsEventsOutput =
         readonly error: { readonly type: "unknown"; readonly message: string }
       }
     }
+  | {
+      readonly id: string
+      readonly metadata?: { readonly [x: string]: unknown }
+      readonly type: "session.next.step.interrupted"
+      readonly durable?: { readonly aggregateID: string; readonly seq: number; readonly version: number }
+      readonly location?: { readonly directory: string; readonly workspaceID?: string }
+      readonly data: { readonly timestamp: number; readonly sessionID: string; readonly assistantMessageID: string }
+    }
   | {
       readonly id: string
       readonly metadata?: { readonly [x: string]: unknown }
@@ -1189,6 +1198,7 @@ export type SessionsMessageOutput = {
         >
         readonly snapshot?: { readonly start?: string; readonly end?: string; readonly files?: ReadonlyArray<string> }
         readonly finish?: string
+        readonly settlement?: "completed" | "failed" | "interrupted"
         readonly cost?: number
         readonly tokens?: {
           readonly input: number

packages/core/src/session/message-updater.ts

@@ -210,6 +210,7 @@ export function update(adapter: Adapter, event: SessionEvent.Event) {
         return updateOwnedAssistant(event.data.assistantMessageID, (draft) => {
           draft.time.completed = event.data.timestamp
           draft.finish = event.data.finish
+          draft.settlement = "completed"
           draft.cost = event.data.cost
           draft.tokens = event.data.tokens
           if (event.data.snapshot || event.data.files)
@@ -224,9 +225,16 @@ export function update(adapter: Adapter, event: SessionEvent.Event) {
         return updateOwnedAssistant(event.data.assistantMessageID, (draft) => {
           draft.time.completed = event.data.timestamp
           draft.finish = "error"
+          draft.settlement = "failed"
           draft.error = event.data.error
         })
       },
+      "session.next.step.interrupted": (event) => {
+        return updateOwnedAssistant(event.data.assistantMessageID, (draft) => {
+          draft.time.completed = event.data.timestamp
+          draft.settlement = "interrupted"
+        })
+      },
       "session.next.text.started": (event) => {
         return updateOwnedAssistant(event.data.assistantMessageID, (draft) => {
           draft.content.push(

packages/core/src/session/projector.ts

@@ -381,6 +381,7 @@ export const layer = Layer.effectDiscard(
     yield* events.project(SessionEvent.Step.Started, (event) => run(db, event))
     yield* events.project(SessionEvent.Step.Ended, (event) => run(db, event))
     yield* events.project(SessionEvent.Step.Failed, (event) => run(db, event))
+    yield* events.project(SessionEvent.Step.Interrupted, (event) => run(db, event))
     yield* events.project(SessionEvent.Text.Started, (event) => run(db, event))
     yield* events.project(SessionEvent.Text.Ended, (event) => run(db, event))
     yield* events.project(SessionEvent.Tool.Input.Started, (event) => run(db, event))

packages/core/src/session/runner/llm.ts

@@ -290,6 +290,7 @@ export const layer = Layer.effect(
           if (settled._tag === "Failure" && isQuestionRejected(settled.cause)) {
             yield* FiberSet.clear(toolFibers)
             yield* withPublication(publisher.failUnsettledTools("Tool execution interrupted"))
+            yield* withPublication(publisher.interruptAssistant())
             return yield* Effect.interrupt
           }
           if (
@@ -298,8 +299,7 @@ export const layer = Layer.effect(
           ) {
             yield* FiberSet.clear(toolFibers)
             yield* withPublication(publisher.failUnsettledTools("Tool execution interrupted"))
-            if (publisher.hasActiveAssistant())
+            yield* withPublication(publisher.interruptAssistant())
-              yield* withPublication(publisher.failAssistant("Provider turn interrupted"))
           }
           if (settled._tag === "Failure" && !Cause.hasInterrupts(settled.cause)) {
             const failure = Cause.squash(settled.cause)
@@ -307,7 +307,7 @@ export const layer = Layer.effect(
             yield* withPublication(publisher.failUnsettledTools(`Tool execution failed: ${message}`))
           }
           const stepSettlement = publisher.stepSettlement()
-          if (stepSettlement && !publisher.hasProviderError()) {
+          if (stepSettlement && !publisher.hasProviderError() && !publisher.hasAssistantSettled()) {
             const endSnapshot = yield* snapshots.capture()
             const files =
               startSnapshot && endSnapshot

packages/core/src/session/runner/publish-llm-event.ts

@@ -66,15 +66,13 @@ export const createLLMEventPublisher = (events: EventV2.Interface, input: Input)
   >()
   const timestamp = DateTime.now
   let assistantMessageID: SessionMessage.ID | undefined
-  let assistantActive = false
+  let assistantSettled = false
-  let assistantFailed = false
   let providerFailed = false
-  let stepSettlement: { readonly finish: string; readonly tokens: ReturnType<typeof tokens> } | undefined
+  let stepSettlement: { readonly finish: SessionMessage.Finish; readonly tokens: ReturnType<typeof tokens> } | undefined
 
   const startAssistant = Effect.fnUntraced(function* () {
     if (assistantMessageID !== undefined) return assistantMessageID
     assistantMessageID = SessionMessage.ID.create()
-    assistantActive = true
     yield* events.publish(SessionEvent.Step.Started, {
       ...input,
       assistantMessageID,
@@ -196,20 +194,39 @@ export const createLLMEventPublisher = (events: EventV2.Interface, input: Input)
     yield* flushFragments()
   })
 
-  const failAssistant = Effect.fnUntraced(function* (message: string) {
+  const settleAssistant = Effect.fnUntraced(function* (
-    if (assistantFailed) return
+    publish: (assistantMessageID: SessionMessage.ID) => Effect.Effect<void>,
+  ) {
+    if (assistantSettled) return
     yield* flush()
     const assistantMessageID = yield* startAssistant()
-    assistantActive = false
+    assistantSettled = true
-    assistantFailed = true
+    yield* publish(assistantMessageID)
-    yield* events.publish(SessionEvent.Step.Failed, {
-      sessionID: input.sessionID,
-      timestamp: yield* timestamp,
-      assistantMessageID,
-      error: { type: "unknown", message },
-    })
   })
 
+  const failAssistant = (message: string) =>
+    settleAssistant((assistantMessageID) =>
+      Effect.gen(function* () {
+        yield* events.publish(SessionEvent.Step.Failed, {
+          sessionID: input.sessionID,
+          timestamp: yield* timestamp,
+          assistantMessageID,
+          error: { type: "unknown", message },
+        })
+      }),
+    )
+
+  const interruptAssistant = () =>
+    settleAssistant((assistantMessageID) =>
+      Effect.gen(function* () {
+        yield* events.publish(SessionEvent.Step.Interrupted, {
+          sessionID: input.sessionID,
+          timestamp: yield* timestamp,
+          assistantMessageID,
+        })
+      }),
+    )
+
   const failUnsettledTools = Effect.fn("SessionRunner.failUnsettledTools")(function* (
     message: string,
     hostedOnly = false,
@@ -395,7 +412,6 @@ export const createLLMEventPublisher = (events: EventV2.Interface, input: Input)
       }
       case "step-finish":
         yield* flush()
-        assistantActive = false
         if (stepSettlement) return yield* Effect.die("Duplicate step finish")
         stepSettlement = { finish: event.reason, tokens: tokens(event.usage) }
         return
@@ -412,9 +428,10 @@ export const createLLMEventPublisher = (events: EventV2.Interface, input: Input)
     publish,
     flush,
     failAssistant,
+    interruptAssistant,
     failUnsettledTools,
-    hasActiveAssistant: () => assistantActive,
     hasAssistantStarted: () => assistantMessageID !== undefined,
+    hasAssistantSettled: () => assistantSettled,
     hasProviderError: () => providerFailed,
     stepSettlement: () => stepSettlement,
     startAssistant,

packages/core/src/session/runner/to-llm-message.ts

@@ -70,7 +70,7 @@ const toolResult = (tool: SessionMessage.AssistantTool, providerMetadata: Provid
 const assistant = (message: SessionMessage.Assistant, model: Model) => {
   const sameModel =
     String(message.model.providerID) === String(model.provider) && String(message.model.id) === String(model.id)
-  const reuseProviderMetadata = sameModel && message.error === undefined
+  const reuseProviderMetadata = sameModel && message.error === undefined && message.settlement !== "interrupted"
   const content = message.content.flatMap((item): ContentPart[] => {
     if (item.type === "text") return [{ type: "text", text: item.text }]
     if (item.type === "reasoning")

packages/core/test/session-runner-message.test.ts

@@ -327,7 +327,7 @@ Recent work
     ])
   })
 
-  test("drops provider-native continuation metadata from failed assistant turns", () => {
+  test("drops provider-native continuation metadata from interrupted assistant turns", () => {
     const messages = toLLMMessages(
       [
         SessionMessage.Assistant.make({
@@ -361,8 +361,7 @@ Recent work
               time: { created, completed: created },
             }),
           ],
-          finish: "error",
+          settlement: "interrupted",
-          error: { type: "unknown", message: "Provider turn interrupted" },
           time: { created, completed: created },
         }),
       ],

packages/core/test/session-runner.test.ts

@@ -519,6 +519,7 @@ const verifyPartialFlushOnFailure = (kind: FragmentKind) =>
       {
         type: "assistant",
         finish: "error",
+        settlement: "failed",
         error: { type: "unknown", message: "Provider unavailable" },
         content: [fixture.expectedContent],
       },
@@ -542,12 +543,28 @@ const verifyPartialFlushOnInterruption = (kind: FragmentKind) =>
     const fiber = yield* runner.run({ sessionID, force: true }).pipe(Effect.forkChild)
     yield* Deferred.await(streamed)
     yield* Fiber.interrupt(fiber)
+    const { db } = yield* Database.Service
+    const interruptedVersion = SessionEvent.Step.Interrupted.durable?.version
+    expect(interruptedVersion).toBe(2)
+    if (interruptedVersion === undefined) return yield* Effect.die("Step.Interrupted must be durable")
+    const settlements = yield* db
+      .select({ type: EventTable.type })
+      .from(EventTable)
+      .where(eq(EventTable.aggregate_id, sessionID))
+      .all()
+      .pipe(Effect.orDie)
+    expect(
+      settlements.filter(({ type }) =>
+        [SessionEvent.Step.Ended.type, SessionEvent.Step.Failed.type, SessionEvent.Step.Interrupted.type].some((settled) =>
+          type.startsWith(settled),
+        ),
+      ),
+    ).toEqual([{ type: EventV2.versionedType(SessionEvent.Step.Interrupted.type, interruptedVersion) }])
     expect(yield* session.context(sessionID)).toMatchObject([
       { type: "user", text: prompt },
       {
         type: "assistant",
-        finish: "error",
+        settlement: "interrupted",
-        error: { type: "unknown", message: "Provider turn interrupted" },
         content: [
           kind === "tool input"
             ? { type: "tool", id: fragmentID(kind, "interrupted"), state: { status: "error" } }
@@ -2653,6 +2670,7 @@ describe("SessionRunnerLLM", () => {
               state: { status: "error", error: { type: "unknown", message: "Tool execution interrupted" } },
             },
           ],
+          settlement: "interrupted",
         },
       ])
     }),
@@ -2797,6 +2815,7 @@ describe("SessionRunnerLLM", () => {
               state: { status: "error", error: { type: "unknown", message: "Tool execution interrupted" } },
             },
           ],
+          settlement: "interrupted",
         },
       ])
     }),

packages/opencode/test/event-manifest.test.ts

@@ -9,7 +9,7 @@ describe("public event manifest", () => {
     expect(EventManifest.Definitions).toBe(SchemaEventManifest.Definitions)
     expect(EventManifest.Latest).toBe(SchemaEventManifest.Latest)
     expect(EventManifest.Durable).toBe(SchemaEventManifest.Durable)
-    expect(EventManifest.Latest.size).toBe(88)
+    expect(EventManifest.Latest.size).toBe(89)
     expect(EventManifest.Latest.get("session.next.step.ended")).toBe(SessionEvent.Step.Ended)
     expect(EventManifest.Latest.get("todo.updated")).toBe(Todo.Event.Updated)
     expect(EventManifest.Latest.has("ide.installed")).toBe(false)

packages/schema/src/session-event.ts

@@ -165,6 +165,7 @@ export namespace Step {
     schema: {
       ...Base,
       assistantMessageID: SessionMessage.ID,
+      // Step.Ended v2 was originally persisted with an open string schema.
       finish: Schema.String,
       cost: Schema.Finite,
       tokens: Schema.Struct({
@@ -192,6 +193,16 @@ export namespace Step {
     },
   })
   export type Failed = typeof Failed.Type
+
+  export const Interrupted = Event.define({
+    type: "session.next.step.interrupted",
+    ...stepSettlementOptions,
+    schema: {
+      ...Base,
+      assistantMessageID: SessionMessage.ID,
+    },
+  })
+  export type Interrupted = typeof Interrupted.Type
 }
 
 export namespace Text {
@@ -458,6 +469,7 @@ export const DurableDefinitions = Event.inventory(
   Step.Started,
   Step.Ended,
   Step.Failed,
+  Step.Interrupted,
   Text.Started,
   Text.Ended,
   Tool.Input.Started,
@@ -489,6 +501,7 @@ export const Definitions = Event.inventory(
   Step.Started,
   Step.Ended,
   Step.Failed,
+  Step.Interrupted,
   Text.Started,
   Text.Delta,
   Text.Ended,

packages/schema/src/session-message.ts

@@ -21,6 +21,19 @@ export const UnknownError = Schema.Struct({
   message: Schema.String,
 }).annotate({ identifier: "Session.Error.Unknown" })
 
+export const Finish = Schema.Literals([
+  "stop",
+  "length",
+  "tool-calls",
+  "content-filter",
+  "error",
+  "unknown",
+])
+export type Finish = typeof Finish.Type
+
+export const Settlement = Schema.Literals(["completed", "failed", "interrupted"])
+export type Settlement = typeof Settlement.Type
+
 const Base = {
   id: ID,
   metadata: Schema.Record(Schema.String, Schema.Unknown).pipe(optional),
@@ -169,7 +182,9 @@ export const Assistant = Schema.Struct({
     end: Schema.String.pipe(optional),
     files: Schema.Array(RelativePath).pipe(optional),
   }).pipe(optional),
+  // Projected histories predate the typed provider finish model and may contain arbitrary values.
   finish: Schema.String.pipe(optional),
+  settlement: Settlement.pipe(optional),
   cost: Schema.Finite.pipe(optional),
   tokens: Schema.Struct({
     input: Schema.Finite,

packages/schema/test/event-manifest.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, test } from "bun:test"
+import { Schema } from "effect"
 import { FileSystem, Integration, Permission, Project, Reference, Session, Workspace } from "../src"
 import { EventManifest } from "../src/event-manifest"
 import { IdeEvent } from "../src/ide-event"
@@ -9,8 +10,8 @@ import { WorkspaceEvent } from "../src/workspace-event"
 
 describe("public event manifest", () => {
   test("owns the complete public event surface", () => {
-    expect(EventManifest.ServerDefinitions.length).toBe(55)
+    expect(EventManifest.ServerDefinitions.length).toBe(59)
-    expect(EventManifest.Definitions.length).toBe(85)
+    expect(EventManifest.Definitions.length).toBe(89)
     expect(SessionV1.Event.Definitions).toEqual([
       SessionV1.Event.Created,
       SessionV1.Event.Updated,
@@ -23,8 +24,8 @@ describe("public event manifest", () => {
       SessionV1.Event.Diff,
       SessionV1.Event.Error,
     ])
-    expect(EventManifest.Latest.size).toBe(85)
+    expect(EventManifest.Latest.size).toBe(89)
-    expect(EventManifest.Durable.size).toBe(32)
+    expect(EventManifest.Durable.size).toBe(36)
   })
 
   test("uses canonical definitions for current public events", () => {
@@ -42,12 +43,28 @@ describe("public event manifest", () => {
     expect(Reference.Event.Definitions).toEqual([Reference.Event.Updated])
     expect(EventManifest.Latest.has("ide.installed")).toBe(false)
     expect(IdeEvent.Definitions).toEqual([IdeEvent.Installed])
-    expect(EventManifest.Definitions.slice(40, 43)).toEqual([
+    const partDelta = EventManifest.Definitions.indexOf(SessionV1.Event.PartDelta)
+    expect(partDelta).toBeGreaterThanOrEqual(0)
+    expect(EventManifest.Definitions.slice(partDelta, partDelta + 3)).toEqual([
       SessionV1.Event.PartDelta,
       SessionV1.Event.Diff,
       SessionV1.Event.Error,
     ])
+    expect(EventManifest.Latest.get("session.next.step.interrupted")).toBe(SessionEvent.Step.Interrupted)
     expect(EventManifest.Durable.has("session.next.step.ended.1")).toBe(false)
     expect(EventManifest.Durable.get("session.next.step.ended.2")).toBe(SessionEvent.Step.Ended)
   })
+
+  test("decodes legacy Step.Ended v2 finish strings", () => {
+    const event = Schema.decodeUnknownSync(SessionEvent.Step.Ended.data)({
+      sessionID: "ses_legacy",
+      timestamp: 0,
+      assistantMessageID: "msg_legacy",
+      finish: "legacy-provider-reason",
+      cost: 0,
+      tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+    })
+
+    expect(event.finish).toBe("legacy-provider-reason")
+  })
 })

packages/schema/test/session-message.test.ts

@@ -0,0 +1,22 @@
+import { expect, test } from "bun:test"
+import { Schema } from "effect"
+import { SessionMessage } from "../src/session-message"
+
+test("does not model interruption as a provider finish reason", () => {
+  expect(() => Schema.decodeUnknownSync(SessionMessage.Finish)("interrupted")).toThrow()
+  expect(Schema.decodeUnknownSync(SessionMessage.Finish)("error")).toBe("error")
+})
+
+test("decodes projected assistant histories with arbitrary finish strings", () => {
+  const message = Schema.decodeUnknownSync(SessionMessage.Message)({
+    id: "msg_legacy",
+    type: "assistant",
+    agent: "build",
+    model: { id: "model", providerID: "provider" },
+    content: [],
+    finish: "legacy-provider-reason",
+    time: { created: 0, completed: 1 },
+  })
+
+  expect(message).toMatchObject({ type: "assistant", finish: "legacy-provider-reason" })
+})

packages/sdk/js/src/v2/gen/types.gen.ts

@@ -28,6 +28,7 @@ export type Event =
   | EventSessionNextStepStarted
   | EventSessionNextStepEnded
   | EventSessionNextStepFailed
+  | EventSessionNextStepInterrupted
   | EventSessionNextTextStarted
   | EventSessionNextTextDelta
   | EventSessionNextTextEnded
@@ -955,6 +956,15 @@ export type GlobalEvent = {
           error: SessionErrorUnknown
         }
       }
+    | {
+        id: string
+        type: "session.next.step.interrupted"
+        properties: {
+          timestamp: number
+          sessionID: string
+          assistantMessageID: string
+        }
+      }
     | {
         id: string
         type: "session.next.text.started"
@@ -1620,6 +1630,7 @@ export type GlobalEvent = {
     | SyncEventSessionNextStepStarted
     | SyncEventSessionNextStepEnded
     | SyncEventSessionNextStepFailed
+    | SyncEventSessionNextStepInterrupted
     | SyncEventSessionNextTextStarted
     | SyncEventSessionNextTextEnded
     | SyncEventSessionNextReasoningStarted
@@ -2759,6 +2770,7 @@ export type V2Event =
   | V2EventSessionNextStepStarted
   | V2EventSessionNextStepEnded
   | V2EventSessionNextStepFailed
+  | V2EventSessionNextStepInterrupted
   | V2EventSessionNextTextStarted
   | V2EventSessionNextTextDelta
   | V2EventSessionNextTextEnded
@@ -3400,6 +3412,22 @@ export type SyncEventSessionNextStepFailed = {
   }
 }
 
+export type SyncEventSessionNextStepInterrupted = {
+  type: "sync"
+  id: string
+  syncEvent: {
+    type: "session.next.step.interrupted.2"
+    id: string
+    seq: number
+    aggregateID: string
+    data: {
+      timestamp: number
+      sessionID: string
+      assistantMessageID: string
+    }
+  }
+}
+
 export type SyncEventSessionNextTextStarted = {
   type: "sync"
   id: string
@@ -3995,6 +4023,7 @@ export type SessionMessageAssistant = {
     files?: Array<string>
   }
   finish?: string
+  settlement?: "completed" | "failed" | "interrupted"
   cost?: number
   tokens?: {
     input: number
@@ -4289,6 +4318,25 @@ export type SessionNextStepFailed = {
   }
 }
 
+export type SessionNextStepInterrupted = {
+  id: string
+  metadata?: {
+    [key: string]: unknown
+  }
+  type: "session.next.step.interrupted"
+  durable?: {
+    aggregateID: string
+    seq: number | "NaN" | "Infinity" | "-Infinity"
+    version: number | "NaN" | "Infinity" | "-Infinity"
+  }
+  location?: LocationRef
+  data: {
+    timestamp: number
+    sessionID: string
+    assistantMessageID: string
+  }
+}
+
 export type SessionNextTextStarted = {
   id: string
   metadata?: {
@@ -5344,6 +5392,25 @@ export type V2EventSessionNextStepFailed = {
   }
 }
 
+export type V2EventSessionNextStepInterrupted = {
+  id: string
+  metadata?: {
+    [key: string]: unknown
+  }
+  durable?: {
+    aggregateID: string
+    seq: number
+    version: number
+  }
+  location?: LocationRef
+  type: "session.next.step.interrupted"
+  data: {
+    timestamp: number
+    sessionID: string
+    assistantMessageID: string
+  }
+}
+
 export type V2EventSessionNextTextStarted = {
   id: string
   metadata?: {
@@ -6931,6 +6998,16 @@ export type EventSessionNextStepFailed = {
   }
 }
 
+export type EventSessionNextStepInterrupted = {
+  id: string
+  type: "session.next.step.interrupted"
+  properties: {
+    timestamp: number
+    sessionID: string
+    assistantMessageID: string
+  }
+}
+
 export type EventSessionNextTextStarted = {
   id: string
   type: "session.next.text.started"

packages/tui/src/context/data.tsx

@@ -227,6 +227,7 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
             if (!currentAssistant) return
             currentAssistant.time.completed = event.data.timestamp
             currentAssistant.finish = event.data.finish
+            currentAssistant.settlement = "completed"
             currentAssistant.cost = event.data.cost
             currentAssistant.tokens = event.data.tokens
             if (event.data.snapshot)
@@ -239,9 +240,18 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
             if (!currentAssistant) return
             currentAssistant.time.completed = event.data.timestamp
             currentAssistant.finish = "error"
+            currentAssistant.settlement = "failed"
             currentAssistant.error = event.data.error
           })
           break
+        case "session.next.step.interrupted":
+          message.update(event.data.sessionID, (draft) => {
+            const currentAssistant = message.assistant(draft, event.data.assistantMessageID)
+            if (!currentAssistant) return
+            currentAssistant.time.completed = event.data.timestamp
+            currentAssistant.settlement = "interrupted"
+          })
+          break
         case "session.next.text.started":
           message.update(event.data.sessionID, (draft) => {
             message.assistant(draft, event.data.assistantMessageID)?.content.push({

packages/tui/test/cli/tui/data.test.tsx

@@ -370,6 +370,72 @@ test("settles pending tools when a live failure arrives", async () => {
   }
 })
 
+test("marks an interrupted assistant inactive without a finish reason", async () => {
+  const events = createEventSource()
+  const calls = createFetch(undefined, events)
+  let sync!: ReturnType<typeof useData>
+  let ready!: () => void
+  const mounted = new Promise<void>((resolve) => {
+    ready = resolve
+  })
+
+  function Probe() {
+    sync = useData()
+    onMount(ready)
+    return <box />
+  }
+
+  const app = await testRender(() => (
+    <TestTuiContexts>
+      <SDKProvider url="http://test" directory={directory} events={events.source} fetch={calls.fetch}>
+        <ProjectProvider>
+          <DataProvider>
+            <Probe />
+          </DataProvider>
+        </ProjectProvider>
+      </SDKProvider>
+    </TestTuiContexts>
+  ))
+
+  try {
+    await mounted
+    emitEvent(events, {
+      id: "evt_step_started_interrupted",
+      type: "session.next.step.started",
+      properties: {
+        sessionID: "session-interrupted",
+        assistantMessageID: "msg_interrupted",
+        timestamp: 1,
+        agent: "build",
+        model: { id: "model-1", providerID: "provider-1" },
+      },
+    })
+    emitEvent(events, {
+      id: "evt_step_interrupted",
+      type: "session.next.step.interrupted",
+      properties: {
+        sessionID: "session-interrupted",
+        assistantMessageID: "msg_interrupted",
+        timestamp: 2,
+      },
+    })
+
+    await wait(() => {
+      const message = sync.session.message.list("session-interrupted")?.[0]
+      return message?.type === "assistant" && message.time.completed === 2
+    })
+    const assistant = sync.session.message.list("session-interrupted")?.[0]
+    expect(assistant).toMatchObject({
+      type: "assistant",
+      settlement: "interrupted",
+      time: { completed: 2 },
+    })
+    expect(assistant).not.toHaveProperty("finish")
+  } finally {
+    app.renderer.destroy()
+  }
+})
+
 test("renders admitted prompts only after they become model-visible", async () => {
   const events = createEventSource()
   const calls = createFetch(undefined, events)