# pi-extensions

Personal `pi` coding-agent extensions. This context covers the permission
extensions that inspect and re-evaluate Bash commands before they are allowed.

## Language

### Wrappers

**Wrapper**:
A Bash command of the form `<program> [modifier-args] <inner-command>`, where the
authorization question is "what does the inner command do?". Whether a wrapper
may be unwrapped depends on whether its modifier args are transparent.
_Avoid_: command type, prefix command

**Transparent wrapper**:
A wrapper whose modifier args do not change which program the inner command
resolves to or its trust boundary (e.g. `timeout`). Stripping the modifiers and
re-evaluating the inner command is sound: the verdict applies to the same
program that actually runs.
_Avoid_: safe wrapper

**Non-transparent wrapper**:
A wrapper whose modifiers change what the inner command actually does in a way
the command string does not capture — e.g. `env` (its `PATH=` / `LD_PRELOAD`
make the inner name resolve to or load a different program) or `xargs` (its
inner command's arguments are read from stdin). Stripping the modifiers and
re-evaluating the inner command is unsound: the verdict applies to inputs that
are not knowable from the command string.
_Avoid_: unsafe wrapper