Snapif

Snapif scores one tool call. The score is Auto, Review, or Escalate.

Getting started

Build the snapif binary. The cli feature includes http.

cargo install snapif --features cli

From this repo, cargo run --features cli -- --help prints the same commands.

Gate

Write one tool call to call.json:

{"action_id":"tag","name":"list_files","args":{},"trusted":{"user_request":"list the workspace"},"untrusted":null,"script":{"harm":"read","confidence":0.91}}

SNAPIF_BACKEND=fake snapif gate --call call.json

The process prints one word and exits:

Exit	Word	Meaning
0	`auto`	The call may proceed.
10	`review`	A person should look first.
11	`escalate`	Do not run the call.

script is only for SNAPIF_BACKEND=fake. A live score uses typesafe or compatible.

Hook

snapif hook is a Claude Code PreToolUse hook. It reads one JSON object on stdin and prints a permission decision on stdout. A bad body still exits 0 and denies the call, because a hook error would otherwise let the call proceed.

printf '%s\n' '{"tool_name":"bash","tool_input":{"command":"ls"}}' | SNAPIF_BACKEND=fake snapif hook

Example

This run uses a scripted fake scorer and prints auto:

cargo run --example pre_tool_use

Live score