Xcheck

Xcheck: decide with a cross-check instead of interrupting the user

When this applies

You were about to write something like "Do you want A or B?" or "Should I assume X?". That interruption costs the user a context switch, and most of the time a careful engineer with the same information would just decide. The problem with deciding alone is that a single pass tends to pick whatever came to mind first. Two independent opinions, forced to argue, are cheap and usually enough.

Skip xcheck and ask the user directly when any of these hold:

• The user explicitly said to check with them on this kind of decision
• The action is hard to reverse: deleting data, force-pushing, dropping columns, changing public APIs, publishing, sending messages
• Money, credentials, production systems, or other people's data are involved
• The decision changes the scope or intent of the task rather than how to do it
• You lack information that only the user has (a preference, a deadline, an external constraint) and the agents would just be guessing at it

Skip xcheck and just decide when the choice is trivial or fully determined by existing conventions in the codebase. Xcheck is for the middle band.

Procedure

1. Frame the decision

Write it down before launching anything, in this form:

Decision: <one sentence>
Options: A) ... B) ... (C) ...)
Context that bears on it: <files, conventions, constraints, what the user
  has said so far>
What "correct" means here: <the criterion: least surprising to the user,
  most consistent with the repo, easiest to reverse, etc.>

If you cannot fill in the last line, that is a sign the decision belongs to the user. Escalate.

2. Launch at least two decision agents

Launch them in the same turn, in the background, with the same framing and context.

Mechanics in Claude Code: one Agent call per vantage, all in a single message so they run concurrently. Step 3 requires talking to the SAME agent again with its context intact, which is SendMessage addressed to the agent, not a second Agent call - a new Agent call starts from nothing and turns the cross-pollination round into two more first drafts. If your harness has no way to resume an agent, use degraded mode below rather than faking it.

Give each a different vantage so they do not just agree by default:

• Agent 1, the user's proxy: "Decide as the person who owns this codebase and asked for this task would. Infer their preferences from the repo's conventions, history, and the wording of the request."
• Agent 2, the reviewer: "Decide as the senior engineer who will review this change and maintain it. Weight reversibility, consistency, and what will confuse the next person."
• Optional agent 3, the skeptic: "Argue that both listed options are wrong or that the question is being asked at the wrong level, then pick anyway."

Each agent's prompt:

<framing block from step 1>

Choose one option and commit to it. Give: your choice, the two strongest
reasons, the strongest reason against it, and what evidence would flip you.
Keep it under 200 words. Do not ask questions; decide with what you have.

Agents do not see each other's answers in this round.

3. Cross-pollinate

Once all answers are in, resume each agent (SendMessage, not a fresh Agent call) with the others' answers:

Here are the other decision agents' answers: <answers>.
Revise your choice or defend it. If you change, say what changed your mind.
If you hold, name the exact point of disagreement in one sentence.
End with: CHOICE: <option> CONFIDENCE: <low/medium/high>

One round is normally enough. Run a second only if the first round moved someone and the movement might continue.

4. Resolve

Consensus means all agents end on the same option, or the holdouts are at low confidence and name no disagreement that survives the others' reasons.

• Consensus: proceed with that option. Record it (step 5) and continue the task. Tell the user in one line what was decided and why, so they can object, but do not wait for them.
• No consensus: escalate. The escalation should be better than the question you were originally going to ask, because you now have the disagreement in sharp form:

Need your call on: <decision>
A) <option>: <best argument, one line>
B) <option>: <best argument, one line>
The disagreement comes down to: <one sentence>
I'd lean <X> if you have no preference.

5. Record

Append to <project>/.xcheck-decisions.md (create if missing):

- <date> <decision one-liner> -> <chosen option> [consensus | escalated]
  reason: <one line>

The log lets a later session see what was decided and why instead of re-litigating it, and lets the user audit the calls you made on their behalf.

When to reach for xpollinate instead

Xcheck is the cheap version: two or three agents, one collision round, minutes. If the question is the task rather than a fork inside it - an architecture decision, a serious review, a plan worth arguing over, prior work you suspect is biased - use xpollinate instead, if that skill is installed. It costs more and buys a pre-committed answer, an unsteered control, several genuinely different stances, and a red team.

Degraded mode (no subagents)

Write the two vantage answers yourself, in separate clearly labeled sections, before writing any resolution. It is weaker than independent agents because you know your own first answer while writing the second; compensate by writing the reviewer answer as if the user's-proxy answer is wrong and see whether the objection holds.

Calibration

If the user overrides an xcheck decision, note the override in the log. If you see two or more overrides of the same kind, stop xchecking that kind of decision and ask directly; the agents are missing a preference only the user has.