cursor-delegation

name	cursor-delegation
description	Host-neutral reference for the Cursor Cloud Agent delegation lifecycle, the yellow-cursor CLI's JSON contract, and its safety/idempotency rules. Use when building or reasoning about a surface that delegates work to a Cursor Cloud Agent through the CLI.
user-invocable	false

Cursor Cloud Agent Delegation

What It Does

Describes the lifecycle of delegating work to a Cursor Cloud Agent through the yellow-cursor CLI, and the JSON contract that CLI exposes on every invocation. This is a host-neutral reference: it names no host-specific mechanism (no slash commands, no host environment variables, no host-specific tool-call syntax) so the same description holds for any integration built on top of the CLI.

Two entities matter:

• Agent — a persistent, addressable unit of work against one repository. Created lazily: nothing happens server-side until the first message is sent to it.
• Run — one dispatched execution created by sending a message (the initial delegation prompt, or a later follow-up). A run carries its own status, target branch, and pull request, if any. An agent can accumulate multiple runs over its lifetime.

When to Use

Use this reference when building or reasoning about any surface that delegates work to a Cursor Cloud Agent through the CLI — deciding what to show a user before a billable launch, how to interpret the CLI's JSON output, or how to recover from an ambiguous or failed call.

Usage

Lifecycle

1. Setup — resolve credentials (an API key or a stored login) and the SDK runtime before attempting anything else.
2. Delegate — validate the plan with a zero-network dry run, show it to the person authorizing the spend, get explicit confirmation, then launch for real. Delegation always costs money once confirmed; nothing here should launch without that confirmation step.
3. Follow-up — continue an existing agent's conversation with a new prompt. Also billable, also requires confirmation before sending.
4. Status — poll an agent (and optionally one of its runs). Always re-fetches live rather than trusting cached state, and can reconcile a local record against what the server actually reports.
5. Cancel — stop a specific run. Re-checks the run's state immediately before acting; cancelling an already-finished run is reported as a successful no-op, not an error.
6. Archive / unarchive — lifecycle housekeeping, not deletion. Both are idempotent: archiving an already-archived agent (or unarchiving one that isn't archived) succeeds without a server call.
7. Artifacts / usage — read-only introspection into what a run produced and what it cost. Both may be unsupported depending on SDK/account capability — that is a permanent condition, not something worth retrying.

Safety rules

• No delete. Nothing in this surface can delete an agent, even though the underlying SDK exposes a delete operation. Archiving is as destructive as this gets.
• Confirm before billable action. Delegating and following up both spend money. Never send either without the operator explicitly confirming a plan that was shown to them first.
• Idempotency keys are reused, not regenerated. Every delegate/follow-up call is tagged with an idempotency key — supplied by the caller, or generated once if not. That exact key must be reused for every retry of the same attempt. Minting a new key on retry defeats the point: it lets a genuinely-failed-then-retried call look like two separate launches to the server.
• Ambiguous outcomes are not failures to retry blindly. A network failure that happens after a message has actually been dispatched cannot tell you whether the run was created. That case is reported distinctly from an ordinary network failure specifically so a caller does not treat it as safe to retry. The correct response is to look up the true state (by the known agent id, or by the idempotency key if the id isn't known yet) before deciding what to do next — never re-send automatically.
• No nested delegation. An agent already running inside a remote-delegated context must refuse to delegate or follow up again — that guard exists to prevent runaway chains of paid launches.
• Concurrency is capped per repository, checked before every new launch, with a caller-adjustable limit.

JSON contract essentials

Every invocation of the CLI prints exactly one JSON object to stdout and nothing else (diagnostics go to stderr). The object always has an ok boolean:

• ok:true responses share {ok:true, operation:<name>, ...} plus operation-specific fields.
• ok:false responses share {ok:false, operation:<name>, error:{code, message, retryable, recoveryAction, requestId?}}. Every error names a stable code, whether it's worth retrying (retryable), and what to do about it (recoveryAction) — surface recoveryAction to the operator rather than inventing your own remediation text.
• Delegating and following up always echo an idempotencyKey at the top level, on success and on every failure path (including a plain usage error) — capture it every time, not just on success, since a failed call is exactly when you need it for a correct retry.

Never treat the absence of a field as a value — a missing targetBranch or pullRequestUrl means Cursor hasn't created one yet, not that the launch failed.