feat: add atomic interrupt-and-deliver

ROADMAP.md

@@ -1837,7 +1837,7 @@ The checked TUI items in this phase were pulled forward as an explicit exception
 - [ ] Reconcile uncertain submissions before retrying and implement provider cancellation where available.
 - [ ] Keep steering and follow-ups queued until the pending batch request reaches a terminal state.
 - [x] Implement daemon-owned steer and follow-up semantics at complete tool-call and turn boundaries.
-- [ ] Complete interrupt-and-deliver semantics.
+- [x] Complete interrupt-and-deliver semantics.
 - [x] Queue multiple follow-ups in order.
 - [x] Add `/fork` from a selected user message and `/clone` from the current tip.
 - [ ] Add in-session branch and tree navigation.

SETUP.md

@@ -66,7 +66,7 @@ axl daemon stop --interrupt --yes
 
 Use the same `--unsafe`, `--sandbox`, `--image`, or `--socket` selection as the running daemon. Status and stop do not require provider credentials. Restart refuses to switch data directories. Stop and restart refuse active work unless `--interrupt` explicitly authorizes cancellation. `--yes` confirms disconnecting clients. A changed confirmation snapshot requires a fresh command. Exit codes are 0 for success, 1 for errors, 2 for refused or stale confirmation, and 3 for a missing daemon on status or stop. Restart starts a missing daemon.
 
-An incompatible session wire fails loudly and points to these commands. No daemon is automatically replaced on a version mismatch. Host-control version 1 operates independently of session wire version 11 on a separate connection to the same owner-only Unix socket. It does not bypass the session handshake.
+An incompatible session wire fails loudly and points to these commands. No daemon is automatically replaced on a version mismatch. Host-control version 1 operates independently of session wire version 12 on a separate connection to the same owner-only Unix socket. It does not bypass the session handshake.
 
 If graceful cleanup fails or exceeds the host's ten-second wait, inspect `axl daemon status`. Shutdown can still be running. The TUI offers a separate force confirmation when available. From the CLI, explicitly request:
 

docs/architecture/web-protocol.md

@@ -13,7 +13,7 @@ This document specifies typed RPC, negotiation, errors, package ownership, and t
 
 ## Current baseline
 
-Wire version 11 uses newline-delimited JSON over a Unix socket. It includes typed request and result envelopes, initialization, capability negotiation, structured errors, idempotency keys, subscription identities, paged snapshots, acknowledged opaque cursors, presence, daemon security reporting, direct shell events, transient activity, session-bound blobs, workspace review, session profiles, web-tool selection, manual compaction, steering, follow-ups, and canonical model-retry attempts.
+Wire version 12 uses newline-delimited JSON over a Unix socket. It includes typed request and result envelopes, initialization, capability negotiation, structured errors, idempotency keys, subscription identities, paged snapshots, acknowledged opaque cursors, presence, daemon security reporting, direct shell events, transient activity, session-bound blobs, workspace review, session profiles, web-tool selection, manual compaction, steering, follow-ups, atomic interrupt-and-deliver, and canonical model-retry attempts.
 
 The TUI consumes these contracts through `packages/sdk`. Version 11 adds daemon-owned model request settings plus canonical effective-request events. Host-control version 1 remains separate from session wire negotiation and is available only to trusted process hosts.
 
@@ -61,8 +61,9 @@ session.resume
 session.fork
 session.clone
 session.send.prompt
-session.send.steer
-session.send.follow_up
+session.steer
+session.follow_up
+session.interrupt_deliver
 session.queue.enqueue
 session.queue.requeue
 session.shell
@@ -227,6 +228,7 @@ The following table lists the additional errors each method may return. The expo
 | `session.fork` | `unknown_session`, `event_migration_required`, `corrupt_session`, `operation_active`, `invalid_fork_point`, `invalid_idempotency_key`, `idempotency_conflict`, `content_too_large` |
 | `session.clone` | `unknown_session`, `event_migration_required`, `corrupt_session`, `operation_active`, `empty_session`, `invalid_idempotency_key`, `idempotency_conflict`, `content_too_large` |
 | `session.send` | `unknown_session`, `event_migration_required`, `operation_active`, `invalid_idempotency_key`, `idempotency_conflict`, `blob_not_owned`, `blob_missing`, `blob_corrupt`, `content_too_large` |
+| `session.interruptAndDeliver` | `unknown_session`, `event_migration_required`, `operation_active`, `invalid_idempotency_key`, `idempotency_conflict`, `blob_not_owned`, `blob_missing`, `blob_corrupt`, `content_too_large` |
 | `session.queue.enqueue` | `unknown_session`, `event_migration_required`, `invalid_idempotency_key`, `idempotency_conflict`, `blob_not_owned`, `blob_missing`, `blob_corrupt`, `content_too_large` |
 | `session.queue.requeue` | `unknown_session`, `event_migration_required`, `unknown_queue_item`, `queue_not_paused`, `invalid_idempotency_key`, `idempotency_conflict`, `content_too_large` |
 | `session.shell` | `unknown_session`, `event_migration_required`, `operation_active`, `idempotency_conflict`, `content_too_large` |
@@ -401,7 +403,7 @@ interface SessionDisposeResult {
 
 `delivery: "prompt"` is ordinary prompt behavior. The version-7 `session.steer` and `session.followUp` methods remain available in version 8. The `session.send` delivery variants `steer` and `follow_up` remain unavailable until their separate capabilities are implemented, and clients must not simulate them.
 
-`session.send` completes when the turn reaches a canonical terminal assistant event or error. Detaching does not cancel it. `session.interrupt` is the session-operation cancellation path.
+`session.send` completes when the turn reaches a canonical terminal assistant event or error. Detaching does not cancel it. `session.interrupt` is the session-operation cancellation path. `session.interruptAndDeliver` atomically stops active work at a safe boundary and delivers its replacement content exactly once; when no operation is active, it behaves as an ordinary send.
 
 Queued prompts use `session.queue.enqueue` and `session.queue.requeue`. Enqueue records prompt content and priority in canonical history before returning. The daemon appends lifecycle events as an item is queued, started, paused after restart, and explicitly re-queued. Pending items are never executed automatically after restart. Every attachment derives the same queue from those events.
 

packages/daemon/src/daemon.ts

@@ -850,6 +850,23 @@ export class AxlDaemon {
     }
   }
 
+  private interruptTargetOperationId(
+    sessionId: SessionId,
+  ): ReturnType<typeof parseOperationId> | undefined {
+    const active = this.sessions.activeOperationId(sessionId);
+    if (active !== undefined) return active;
+    for (const request of this.admitted.values()) {
+      if (request.method === "session.send" && request.params.sessionId === sessionId) {
+        const operationId = request.idempotencyKey;
+        if (operationId !== undefined) return parseOperationId(operationId, "idempotencyKey");
+      }
+      if (request.method === "session.shell" && request.params.sessionId === sessionId) {
+        return request.params.operationId;
+      }
+    }
+    return undefined;
+  }
+
   private async executeRequest(
     request: WireRequest,
     send: (message: ServerMessage) => void,
@@ -908,25 +925,43 @@ export class AxlDaemon {
         ? parseSessionId(randomUUID(), "intendedSessionId")
         : undefined;
     const affectedOperationId =
-      normalized.method === "session.interrupt"
-        ? this.sessions.activeOperationId(normalized.params.sessionId)
+      normalized.method === "session.interrupt" ||
+      normalized.method === "session.interruptAndDeliver"
+        ? this.interruptTargetOperationId(normalized.params.sessionId)
         : undefined;
     const interactionId =
       normalized.method === "session.interaction.respond"
         ? normalized.params.interactionId
         : undefined;
-    return journal.execute(
-      {
-        idempotencyKey,
-        method: normalized.method as RetryableMutationMethod,
-        requestHash: hashCanonicalRequest(normalized.method, normalized.params as never),
-        ...(params.sessionId === undefined ? {} : { targetSessionId: params.sessionId }),
-        ...(intendedSessionId === undefined ? {} : { intendedSessionId }),
-        ...(affectedOperationId === undefined ? {} : { affectedOperationId }),
-        ...(interactionId === undefined ? {} : { interactionId }),
-      },
-      (acceptance) => this.dispatch(normalized, send, state, acceptance) as never,
-    );
+    const interruptDeliveryOperationId =
+      normalized.method === "session.interruptAndDeliver"
+        ? parseOperationId(idempotencyKey, "idempotencyKey")
+        : undefined;
+    if (interruptDeliveryOperationId !== undefined) {
+      this.sessions.reserveInterruptDelivery(
+        params.sessionId,
+        interruptDeliveryOperationId,
+        affectedOperationId,
+      );
+    }
+    try {
+      return await journal.execute(
+        {
+          idempotencyKey,
+          method: normalized.method as RetryableMutationMethod,
+          requestHash: hashCanonicalRequest(normalized.method, normalized.params as never),
+          ...(params.sessionId === undefined ? {} : { targetSessionId: params.sessionId }),
+          ...(intendedSessionId === undefined ? {} : { intendedSessionId }),
+          ...(affectedOperationId === undefined ? {} : { affectedOperationId }),
+          ...(interactionId === undefined ? {} : { interactionId }),
+        },
+        (acceptance) => this.dispatch(normalized, send, state, acceptance) as never,
+      );
+    } finally {
+      if (interruptDeliveryOperationId !== undefined) {
+        this.sessions.releaseInterruptDelivery(params.sessionId, interruptDeliveryOperationId);
+      }
+    }
   }
 
   private async dispatch(
@@ -1046,6 +1081,15 @@ export class AxlDaemon {
         return this.sessions.steer(request.params.sessionId, request.params.content);
       case "session.followUp":
         return this.sessions.followUp(request.params.sessionId, request.params.content);
+      case "session.interruptAndDeliver":
+        return this.sessions.interruptAndDeliver(
+          request.params.sessionId,
+          request.params.content,
+          this.mutationOperationId(acceptance),
+          acceptance?.affectedOperationId === undefined
+            ? undefined
+            : parseOperationId(acceptance.affectedOperationId, "affectedOperationId"),
+        );
       case "session.compact":
         return this.sessions.compact(request.params.sessionId, request.params.instructions);
       case "session.queue.enqueue":
@@ -1070,7 +1114,12 @@ export class AxlDaemon {
           request.params.excluded,
         );
       case "session.interrupt":
-        return this.sessions.interrupt(request.params.sessionId);
+        return this.sessions.interrupt(
+          request.params.sessionId,
+          acceptance?.affectedOperationId === undefined
+            ? undefined
+            : parseOperationId(acceptance.affectedOperationId, "affectedOperationId"),
+        );
       case "session.reload":
         return this.sessions.reload(request.params.sessionId, this.mutationOperationId(acceptance));
       case "session.configure": {

packages/daemon/src/event-migration.ts

@@ -184,6 +184,7 @@ function eventBlobReferences(event: CanonicalEvent): readonly BlobReference[] {
   if (
     event.type !== "user.message" &&
     event.type !== "assistant.message" &&
+    event.type !== "interrupt.requested" &&
     event.type !== "user.shell" &&
     event.type !== "tool.result"
   ) {
@@ -199,6 +200,7 @@ function externalizeTextContent(
   if (
     event.type !== "user.message" &&
     event.type !== "assistant.message" &&
+    event.type !== "interrupt.requested" &&
     event.type !== "user.shell" &&
     event.type !== "tool.result"
   ) {

packages/daemon/src/session-artifact.ts

@@ -63,6 +63,7 @@ function blobReferences(events: readonly CanonicalEvent[]): readonly BlobReferen
       event.type !== "user.message" &&
       event.type !== "assistant.message" &&
       event.type !== "queue.enqueued" &&
+      event.type !== "interrupt.requested" &&
       event.type !== "user.shell" &&
       event.type !== "tool.result"
     ) {