From 5deef980dd7a1ceba4d4e53bef737033fc3a3a40 Mon Sep 17 00:00:00 2001
From: Aiden Cline <aidenpcline@gmail.com>
Date: Fri, 3 Jul 2026 16:55:18 -0500
Subject: [PATCH] refactor(core): handle form cancellation in runner

---
 packages/core/src/form.ts               |  2 ++
 packages/core/src/session/runner/llm.ts | 14 ++++++--------
 packages/core/src/tool/question.ts      |  3 +--
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/packages/core/src/form.ts b/packages/core/src/form.ts
index d49129b3b81..fbb286eba04 100644
--- a/packages/core/src/form.ts
+++ b/packages/core/src/form.ts
@@ -63,6 +63,8 @@ export class InvalidFormError extends Schema.TaggedErrorClass<InvalidFormError>(
   message: Schema.String,
 }) {}
 
+export class CancelledError extends Schema.TaggedErrorClass<CancelledError>()("Form.CancelledError", {}) {}
+
 export type CreateInput =
   | (Omit<Form.FormInfo, "id"> & { readonly id?: ID })
   | (Omit<Form.UrlInfo, "id"> & { readonly id?: ID })
diff --git a/packages/core/src/session/runner/llm.ts b/packages/core/src/session/runner/llm.ts
index 0aeaa0e0525..bd9fdcf9c9a 100644
--- a/packages/core/src/session/runner/llm.ts
+++ b/packages/core/src/session/runner/llm.ts
@@ -16,7 +16,7 @@ import { Config } from "../../config"
 import { Database } from "../../database/database"
 import { EventV2 } from "../../event"
 import { Location } from "../../location"
-import { QuestionV2 } from "../../question"
+import { Form } from "../../form"
 import { SystemContext } from "../../system-context/index"
 import { SystemContextBuiltIns } from "../../system-context/builtins"
 import { InstructionContext } from "../../instruction-context"
@@ -149,9 +149,8 @@ const layer = Layer.effect(
     const awaitToolFibers = (fibers: FiberSet.FiberSet<void, ToolOutputStore.Error>) =>
       Effect.raceFirst(FiberSet.join(fibers), FiberSet.awaitEmpty(fibers))
 
-    // Match V1: dismissing a question halts the loop instead of becoming model-facing tool output.
-    const isQuestionRejected = (cause: Cause.Cause<unknown>) =>
-      cause.reasons.some((reason) => Cause.isDieReason(reason) && reason.defect instanceof QuestionV2.RejectedError)
+    const isFormCancelled = (cause: Cause.Cause<unknown>) =>
+      cause.reasons.some((reason) => Cause.isDieReason(reason) && reason.defect instanceof Form.CancelledError)
 
     const loadSystemContext = (agent: AgentV2.Selection, sessionID: SessionSchema.ID) =>
       Effect.all(
@@ -341,14 +340,13 @@ const layer = Layer.effect(
           if (streamInterrupted) yield* FiberSet.clear(toolFibers)
           const settled = yield* restore(awaitToolFibers(toolFibers)).pipe(Effect.exit)
           const toolsInterrupted = settled._tag === "Failure" && Cause.hasInterrupts(settled.cause)
-          const questionDismissed = settled._tag === "Failure" && isQuestionRejected(settled.cause)
+          const formCancelled = settled._tag === "Failure" && isFormCancelled(settled.cause)
 
-          if (questionDismissed || streamInterrupted || toolsInterrupted) {
+          if (formCancelled || streamInterrupted || toolsInterrupted) {
             yield* FiberSet.clear(toolFibers)
             yield* serialized(publisher.failUnsettledTools("Tool execution interrupted"))
             yield* serialized(publisher.failAssistant("Step interrupted"))
-            // Match V1: dismissing a question halts the loop like an interruption.
-            if (questionDismissed) return yield* Effect.interrupt
+            if (formCancelled) return yield* Effect.interrupt
           }
           // A settled tool fiber failure is one of two things. A defect from a tool
           // implementation becomes a failed tool call the model can read, and the step still
diff --git a/packages/core/src/tool/question.ts b/packages/core/src/tool/question.ts
index 463997cd264..20be82f06cc 100644
--- a/packages/core/src/tool/question.ts
+++ b/packages/core/src/tool/question.ts
@@ -94,8 +94,7 @@ export const Plugin = {
                     .pipe(Effect.orDie),
                 ),
                 Effect.flatMap((state) => {
-                  // The runner halts the loop on this exact defect (session/runner/llm.ts).
-                  if (state.status !== "answered") return Effect.die(new QuestionV2.RejectedError())
+                  if (state.status !== "answered") return Effect.die(new Form.CancelledError())
                   return Effect.succeed({
                     answers: input.questions.map((_, index): QuestionV2.Answer => {
                       const value = state.answer[`q${index}`]