Command Syntax

Slash commands authored under .rulesync/commands/*.md use a universal syntax that mirrors Claude Code's command placeholders. When rulesync generates a tool-specific command file, it rewrites these placeholders into the syntax that the target tool understands. The reverse rewrite happens on import, so a rulesync ↔ tool round-trip preserves the original universal form.

Universal placeholders

Placeholder	Meaning
$ARGUMENTS	The full argument string the user supplied when invoking the command.
!`cmd`	Inline shell expansion. The agent runs cmd and substitutes its output.

These are written exactly as Claude Code accepts them, so writing a rulesync command body is the same as writing a Claude Code command body.

Per-tool translation

The table below shows how each placeholder is translated for the supported tools. "pass-through" means the placeholder is emitted verbatim because the target tool already understands the universal form.

Tool	$ARGUMENTS	!`cmd`
Claude Code	pass-through	pass-through
Codex CLI[^codex]	pass-through (literal)	pass-through (literal)
Pi	pass-through	pass-through (literal)[^pi]
Other tools[^1]	pass-through (literal)	pass-through (literal)

[^1]: Tools not listed do not have a documented translation; their command body is emitted as-is.

[^codex]: Codex CLI prompt files are forwarded to the LLM verbatim; the placeholders are passed to the model as literal text rather than being substituted by the engine.

[^pi]: Pi natively expands $ARGUMENTS (along with $1, $2, $@), so $ARGUMENTS is a real pass-through there. rulesync still emits !`cmd` verbatim for Pi, but does not assume Pi expands inline shell snippets — treat that placeholder as literal text on Pi's side.

The translation also runs in reverse when you import an existing tool command file via rulesync import, so a tool-native placeholder is rewritten back to the universal form in the generated .rulesync/commands/*.md.

Example

Given the following rulesync command:

---
targets: ["claudecode"]
description: "Summarize git diff"
---

Summarize the diff:
!`git diff`

Focus on $ARGUMENTS.

rulesync generates .claude/commands/summarize.md, passing the placeholders through verbatim because Claude Code already understands the universal form.

Notes

• If you author a command with explicit tool-specific syntax (e.g. you write a tool-native placeholder directly in a rulesync command body), rulesync does not re-translate the already-tool-native form. Stick to the universal placeholders to keep commands portable across tools.
• The translation is purely textual and is applied to the entire body. It does not skip fenced or inline code blocks, so ```js\n$ARGUMENTS\n``` in a rulesync body will still be rewritten when generating tool output. There is no escape syntax for the universal placeholders — backslashes are not consumed by the regex, so \$ARGUMENTS is rewritten alongside the placeholder rather than producing a literal $ARGUMENTS.
• The shell expansion regex matches a single backtick-delimited segment without embedded backticks or newlines (!`...`). Multi-line shell snippets are not supported, and a backtick inside the command body is not allowed.