defer

name	defer
description	Defer execution of a slash-command or prompt until a timer elapses. Starts a background polling timer that prints "TIMER DONE" on stdout, then executes the deferred prompt.
allowed-tools	Bash, Read, Write, TaskStop

defer — run a prompt after a timer

Session-scoped deferred execution. Parses /defer <duration>: <prompt>, launches a background polling timer that emits TIMER DONE, then runs <prompt> exactly as if the user just typed it.

NOT cross-session — the timer dies with the Claude Code process. Point users at /schedule for anything longer-lived.

Subcommands

Form	Action
/defer <duration>: <prompt>	Arm a new timer.
/defer list	Show pending defers.
/defer cancel <id>	Cancel one defer.
/defer cancel all	Cancel every pending defer.

<id> = the background-bash shell id returned at arm time. Cancellation uses TaskStop with task_id=<id>.

Argument format

/defer <duration>: <deferred prompt>

• Duration: integer + unit, case-insensitive. Units: s|sec|secs|second|seconds, m|min|mins|minute|minutes, h|hr|hrs|hour|hours. Whitespace optional.
• Separator: the first : after the duration. Everything after, trimmed, is the prompt. The prompt may contain :, /<cmd>, @file.
• Reject with one short error line if: duration ≤ 0, duration > 21600 (6h), non-integer (1.5h → suggest 90m), empty prompt, or shape mismatch. Do not guess.

Informal regex: ^\s*(\d+)\s*([A-Za-z]+)\s*:\s*(\S.*?)\s*$, unit lower-cased before matching.

Workflow — arm

1. Parse → duration_seconds, deferred_prompt. Apply rejection rules.

2. Launch Bash with run_in_background: true, using the polling-timer script in references/timer-script.md. Capture the returned <sid>. Do not interpolate the prompt into the script.

3. Persist /tmp/claude-defer-<sid>.txt:

   END_TS=<unix_end_time>
   <deferred_prompt verbatim>
   

4. Confirm with one line: Deferring for <human_duration> (id <sid>). Will run: <≤80-char prompt summary>

5. End the turn. Do not poll, sleep, or Monitor — the harness re-invokes on completion.

Workflow — wakeup

The completion notification's <task-id> IS the shell id <sid>. Use it directly.

1. Read the bash output (path is in the notification). Last non-empty line must be TIMER DONE AND exit code 0 → proceed. Otherwise → interrupted (see references/edge-cases.md).
2. Read /tmp/claude-defer-<sid>.txt, strip the leading END_TS=…\n. If missing/malformed, report and stop.
3. Announce: Timer elapsed. Executing: <summary>.
4. Execute the prompt body exactly as if the user just typed it (leading /<name> → Skill; otherwise → normal request).
5. Clean up: rip /tmp/claude-defer-<sid>.txt (env hook blocks rm).

Workflow — list

Glob /tmp/claude-defer-*.txt. For each, parse END_TS from line 1, summarize the prompt, render a compact table. Format details in references/examples.md.

Workflow — cancel

1. TaskStop with task_id=<sid>. On error (unknown id), report and stop.
2. rip /tmp/claude-defer-<sid>.txt.
3. Print Cancelled defer <sid>. End turn. The completion notification will fire and the wakeup handler's interrupted branch will recognise the cancel.

cancel all → enumerate sids from the temp-file glob, do the above for each.

References

• references/timer-script.md — the polling-timer bash script (verbatim, do not modify).
• references/examples.md — concrete examples for arm / list / cancel / invalid input.
• references/edge-cases.md — interrupted branch, stale files, concurrency, environmental gotchas.