What causes "Handoff cancelled" in can1357/oh-my-pi?

Treat this as an expected cancellation: catch and return quietly instead of retrying

can1357/oh-my-pi · info · Error

Handoff cancelled

Error message

Handoff cancelled

What it means

throwIfHandoffAborted translates an aborted AbortSignal into a typed error for the handoff flow. When the signal was aborted with a plain DOMException AbortError (no richer reason), it throws Error("Handoff cancelled") so callers can distinguish a user/environment cancellation from other abort causes.

Source

Thrown at packages/coding-agent/src/session/session-handoff.ts:30

import type { Message, Model, ServiceTier, SimpleStreamOptions } from "@oh-my-pi/pi-ai";
import { logger, Snowflake } from "@oh-my-pi/pi-utils";
import type { ModelRegistry } from "../config/model-registry";
import type { Settings } from "../config/settings";
import { obfuscateProviderContext } from "../secrets/message-transform";
import type { SecretObfuscator } from "../secrets/obfuscator";
import type { HandoffResult, SessionHandoffOptions } from "./agent-session-types";
import type { SessionManager } from "./session-manager";

function createHandoffFileName(date = new Date()): string {
	const fileTimestamp = date.toISOString().replace(/[:.]/g, "-");
	return `handoff-${fileTimestamp}.md`;
}

function throwIfHandoffAborted(signal: AbortSignal): void {
	if (!signal.aborted) return;
	const reason = signal.reason;
	if (reason instanceof DOMException && reason.name === "AbortError") {
		throw new Error("Handoff cancelled");
	}
	if (reason instanceof Error) throw reason;
	if (typeof reason === "string" && reason.length > 0) throw new Error(reason);
	throw new Error("Handoff aborted by session");
}

/** Capabilities borrowed from the owning AgentSession. */
export interface SessionHandoffHost {
	agent: Agent;
	sessionManager: SessionManager;
	settings: Settings;
	modelRegistry: ModelRegistry;
	sideStreamFn: StreamFn;
	obfuscator: SecretObfuscator | undefined;
	model(): Model | undefined;
	thinkingLevel(): ThinkingLevel | undefined;
	sessionId(): string;
	baseSystemPrompt(): string[];

View on GitHub (pinned to 9690622007)

Solutions

Treat this as an expected cancellation: catch and return quietly instead of retrying
If the handoff should proceed, restart it with a fresh, non-aborted AbortController
Find what aborted the signal (user action, timeout, teardown) and remove or delay that abort
Surface a 'cancelled' status to the user rather than an error report

Example fix

// before
await handoff.generateDocument(...); // throws 'Handoff cancelled'
// after
try {
  await handoff.generateDocument(...);
} catch (err) {
  if (err.message === "Handoff cancelled") return; // expected cancel
  throw err;
}

Defensive patterns

Strategy: try-catch

Validate before calling

if (handoffSignal.aborted) return; // already cancelled; skip the call

Try / catch

try {
  await handoff.generateDocument(handoffSignal);
} catch (err) {
  if (err instanceof Error && err.message === "Handoff cancelled") return; // expected
  throw err;
}

Prevention

Check signal.aborted before starting handoff work
Distinguish cancellation from failure in your error handling
Abort with descriptive reasons when you own the controller
Avoid aborting handoff signals during routine UI interactions

When it happens

Trigger: generateDocument calling throwIfHandoffAborted(handoffSignal) after the signal was aborted via controller.abort() with no custom reason (default AbortError).

Common situations: User cancelled the handoff prompt; session teardown or timeout aborted the controller mid-generation; upstream compaction logic aborted the handoff attempt.

Related errors

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/657cb20f26b4d2cb. Report an issue: GitHub.