feat(core): let form cancellation carry a message (#52137)

packages/cli/src/run/noninteractive.ts

@@ -67,6 +67,9 @@ type FormRequest = Extract<V2Event, { type: "form.created" }>["data"]["form"]
 // attached client must not cancel input that may belong to another session.
 const GLOBAL_FORM_SESSION_ID = "global"
 
+const QUESTION_CANCELLED_FEEDBACK =
+  "This non-interactive run cannot ask the user questions, so the question was cancelled. Continue without an answer; make reasonable assumptions and state them."
+
 const PERMISSION_REJECTED_FEEDBACK =
   "This non-interactive run cannot ask the user for permission, so the request was rejected. Continue without this action."
 
@@ -182,15 +185,23 @@ export async function runNonInteractivePrompt(input: Input) {
     }
   }
 
-  const cancelForm = async (request: Pick<FormRequest, "id" | "sessionID">) => {
+  const cancelForm = async (request: Pick<FormRequest, "id" | "sessionID" | "metadata">) => {
+    // Nobody can answer a question here. Outside V1 compatibility, cancel it with a message so the
+    // question tool fails as ordinary model-visible output and the model continues without an answer.
+    const continuing = request.metadata?.kind === "question" && input.compatibility !== "v1"
     try {
       await input.client.session.form.cancel(
-        { sessionID: request.sessionID, formID: request.id },
+        {
+          sessionID: request.sessionID,
+          formID: request.id,
+          ...(continuing ? { message: QUESTION_CANCELLED_FEEDBACK } : {}),
+        },
         ...formRequestOptions(request.sessionID === GLOBAL_FORM_SESSION_ID ? input.location : undefined),
       )
     } catch (error) {
       if (!formAlreadySettled(error)) throw error
     }
+    if (continuing) return
     formCancelled = true
     if (input.compatibility !== "v1") process.exitCode = 1
   }

packages/client/src/effect/api/api.ts

@@ -1414,7 +1414,11 @@ export type SessionFormReplyOperation<E = never> = (
   input: SessionFormReplyInput,
 ) => Effect.Effect<SessionFormReplyOutput, E>
 
-export type SessionFormCancelInput = { readonly sessionID: string; readonly formID: Form.ID }
+export type SessionFormCancelInput = {
+  readonly sessionID: string
+  readonly formID: Form.ID
+  readonly message?: string | undefined
+}
 export type SessionFormCancelOutput = void
 export type SessionFormCancelOperation<E = never> = (
   input: SessionFormCancelInput,

packages/client/src/effect/generated/client.ts

@@ -735,9 +735,10 @@ const EndpointSessionFormReply = (raw: RawClient["server.session"]) => (input: S
 
 const EndpointSessionFormCancel = (raw: RawClient["server.session"]) => (input: SessionFormCancelInput) =>
   preserveEffect<SessionFormCancelOutput>()(
-    raw["session.form.cancel"]({ params: { sessionID: input["sessionID"], formID: input["formID"] } }).pipe(
-      Effect.mapError(mapClientError),
-    ),
+    raw["session.form.cancel"]({
+      params: { sessionID: input["sessionID"], formID: input["formID"] },
+      query: { message: input["message"] },
+    }).pipe(Effect.mapError(mapClientError)),
   )
 
 const EndpointSessionEnvironment = (raw: RawClient["server.session"]) => (input: SessionEnvironmentInput) =>

packages/client/src/promise/generated/client.ts

@@ -1058,6 +1058,7 @@ export function make(options: ClientOptions) {
             {
               method: "DELETE",
               path: `/api/session/${encodeURIComponent(input.sessionID)}/form/${encodeURIComponent(input.formID)}`,
+              query: { message: input["message"] },
               successStatus: 204,
               declaredStatuses: [400, 401, 404, 409],
               empty: true,

packages/client/src/promise/generated/types.ts

@@ -1897,7 +1897,10 @@ export type FormField =
   | FormMultiselectField
   | FormExternalField
 
-export type FormState = { status: "pending" } | { status: "answered"; answer: FormAnswer } | { status: "cancelled" }
+export type FormState =
+  | { status: "pending" }
+  | { status: "answered"; answer: FormAnswer }
+  | { status: "cancelled"; message?: string }
 
 export type CredentialKey = {
   type: "key"
@@ -5460,6 +5463,7 @@ export type SessionFormReplyOutput = void
 export type SessionFormCancelInput = {
   readonly sessionID: { readonly sessionID: string; readonly formID: string }["sessionID"]
   readonly formID: { readonly sessionID: string; readonly formID: string }["formID"]
+  readonly message?: { readonly message?: string | undefined }["message"]
 }
 
 export type SessionFormCancelOutput = void

packages/core/src/form.ts

@@ -74,6 +74,10 @@ export interface ReplyInput {
   readonly answer: Answer
 }
 
+export interface CancelOptions {
+  readonly message?: string
+}
+
 export interface ListInput {
   readonly sessionID?: Form.Info["sessionID"]
 }
@@ -86,7 +90,7 @@ export interface Interface {
   readonly list: (input?: ListInput) => Effect.Effect<ReadonlyArray<Info>>
   readonly state: (id: ID) => Effect.Effect<State, NotFoundError>
   readonly reply: (input: ReplyInput) => Effect.Effect<void, AlreadySettledError | InvalidAnswerError | NotFoundError>
-  readonly cancel: (id: ID) => Effect.Effect<void, AlreadySettledError | NotFoundError>
+  readonly cancel: (id: ID, options?: CancelOptions) => Effect.Effect<void, AlreadySettledError | NotFoundError>
 }
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/Form") {}
@@ -192,12 +196,15 @@ export const layer = Layer.effect(
       ),
     )
 
-    const cancel = Effect.fn("Form.cancel")((id: ID) =>
+    const cancel = Effect.fn("Form.cancel")((id: ID, options?: CancelOptions) =>
       Effect.uninterruptible(
         Effect.gen(function* () {
           const entry = yield* requireEntry(id)
           if (entry.state.status !== "pending") return yield* new AlreadySettledError({ id })
-          const next: TerminalState = { status: "cancelled" }
+          const next: TerminalState = {
+            status: "cancelled",
+            ...(options?.message === undefined ? {} : { message: options.message }),
+          }
           yield* bus.publish(Form.Event.Cancelled, { id, sessionID: entry.form.sessionID })
           yield* Cache.set(forms, id, { ...entry, state: next })
           yield* Deferred.succeed(entry.deferred, next)

packages/core/src/tool/plugin/question.ts

@@ -90,6 +90,10 @@ export const Plugin = {
                   // Deliberate defect tunnel (see Permission.assert): a dismissal must dodge
                   // leaf `mapError` blankets so it never becomes model-facing tool output; it
                   // resurfaces as a typed failure at SessionModelRequest.executeTool.
+                  // A dismissal with a message (e.g. from a non-interactive client) is ordinary
+                  // model-facing feedback: the model continues instead of the step ending.
+                  if (state.status === "cancelled" && state.message !== undefined)
+                    return Effect.fail(new ToolFailure({ message: state.message }))
                   if (state.status === "cancelled") return Effect.die(new CancelledError())
                   const output = {
                     answers: input.questions.map((_, index): Question.Answer => {

packages/protocol/openapi.json

@@ -4566,7 +4566,7 @@
             }
           }
         },
-        "description": "Cancel a pending form.",
+        "description": "Cancel a pending form, optionally telling the asker why it was not answered.",
         "summary": "Cancel form"
       }
     },
@@ -4591,6 +4591,21 @@
               "pattern": "^frm_"
             },
             "required": true
+          },
+          {
+            "name": "message",
+            "in": "query",
+            "schema": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ]
+            },
+            "required": false
           }
         ],
         "security": [],
@@ -14170,6 +14185,9 @@
               "status": {
                 "type": "string",
                 "enum": ["cancelled"]
+              },
+              "message": {
+                "type": "string"
               }
             },
             "required": ["status"],

packages/protocol/src/groups/session.ts

@@ -855,6 +855,7 @@ export const makeSessionGroup = <
     .add(
       HttpApiEndpoint.delete("session.form.cancel", "/api/session/:sessionID/form/:formID", {
         params: { sessionID: Schema.String, formID: Form.ID },
+        query: Schema.Struct({ message: Schema.optional(Schema.String) }),
         success: HttpApiSchema.NoContent,
         error: [SessionNotFoundError, FormAlreadySettledError, FormNotFoundError],
       })
@@ -863,7 +864,7 @@ export const makeSessionGroup = <
           OpenApi.annotations({
             identifier: "session.form.cancel",
             summary: "Cancel form",
-            description: "Cancel a pending form.",
+            description: "Cancel a pending form, optionally telling the asker why it was not answered.",
           }),
         ),
     )

packages/schema/src/form.ts

@@ -149,7 +149,8 @@ export type Answer = typeof Answer.Type
 export const State = Schema.Union([
   Schema.Struct({ status: Schema.Literal("pending") }),
   Schema.Struct({ status: Schema.Literal("answered"), answer: Answer }),
-  Schema.Struct({ status: Schema.Literal("cancelled") }),
+  // A message tells the asker why nobody answered, e.g. a non-interactive client.
+  Schema.Struct({ status: Schema.Literal("cancelled"), message: Schema.String.pipe(optional) }),
 ])
   .pipe(Schema.toTaggedUnion("status"))
   .annotate({ identifier: "Form.State" })

packages/server/src/handlers/session.ts

@@ -692,7 +692,7 @@ export const SessionHandler = HttpApiBuilder.group(Api, "server.session", (handl
         "session.form.cancel",
         Effect.fn(function* (ctx) {
           const owned = yield* requireOwnedForm(ctx.params.sessionID, ctx.params.formID)
-          yield* owned.form.cancel(ctx.params.formID).pipe(
+          yield* owned.form.cancel(ctx.params.formID, { message: ctx.query.message }).pipe(
             Effect.catchTags({
               "Form.AlreadySettledError": (error) =>
                 new FormAlreadySettledError({ id: error.id, message: error.message }),

services/www/openapi.json

@@ -4566,7 +4566,7 @@
             }
           }
         },
-        "description": "Cancel a pending form.",
+        "description": "Cancel a pending form, optionally telling the asker why it was not answered.",
         "summary": "Cancel form"
       }
     },
@@ -4591,6 +4591,21 @@
               "pattern": "^frm_"
             },
             "required": true
+          },
+          {
+            "name": "message",
+            "in": "query",
+            "schema": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ]
+            },
+            "required": false
           }
         ],
         "security": [],
@@ -14170,6 +14185,9 @@
               "status": {
                 "type": "string",
                 "enum": ["cancelled"]
+              },
+              "message": {
+                "type": "string"
               }
             },
             "required": ["status"],

services/www/public/openapi.json

@@ -4566,7 +4566,7 @@
             }
           }
         },
-        "description": "Cancel a pending form.",
+        "description": "Cancel a pending form, optionally telling the asker why it was not answered.",
         "summary": "Cancel form"
       }
     },
@@ -4591,6 +4591,21 @@
               "pattern": "^frm_"
             },
             "required": true
+          },
+          {
+            "name": "message",
+            "in": "query",
+            "schema": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ]
+            },
+            "required": false
           }
         ],
         "security": [],
@@ -14170,6 +14185,9 @@
               "status": {
                 "type": "string",
                 "enum": ["cancelled"]
+              },
+              "message": {
+                "type": "string"
               }
             },
             "required": ["status"],