The dangerous-command approval gate has rules that flag a shell command
when it overwrites a project `.env` or `config.yaml` — these files hold
API keys, DB passwords, and (for `config.yaml`) the approval policy
itself, so a write to them should require user approval. The matching
`write_file`/`patch` deny on the file-tools side was paired with these
terminal-side rules so neither path is an open door.
The redirection and `tee` rules anchored the sensitive path with
`_COMMAND_TAIL` (`(?:\s*(?:&&|\|\||;).*)?$`), which only tolerates the
rest of the line being empty or a command separator. The problem: in
POSIX shell the redirection target is fixed regardless of what trails it.
`echo secret > .env extra` still truncates `.env` (the `extra` is just
another argument to `echo`), and `echo secret > .env # note` does too
(the `#` starts a comment). Because neither tail is a separator, the old
anchor failed to match and the command sailed through approval — a
prompt-injected step could overwrite a project `.env`/`config.yaml`
unprompted. The system-path redirection rule one line above never had
this restriction and already caught these forms.
The fix introduces `_WRITE_TARGET_BOUNDARY`, a lookahead that only
requires the path token to END at a shell word boundary (whitespace,
quote, separator, redirection operator, `#`, or EOL) rather than
demanding the rest of the line be empty. It is applied to the two
stream-write rules (redirection and `tee`) where the sensitive path is
always a write target. The `cp`/`mv`/`install` rule deliberately keeps
`_COMMAND_TAIL`: there the sensitive file is only a target when it is the
LAST argument (the destination), so requiring end-of-line is correct and
keeps `cp config.yaml backup.yaml` (config.yaml as the source) out of the
deny.
## What does this PR do?
Closes a bypass in the dangerous-command approval gate where a trailing
argument or `#` comment after a `>`/`>>`/`tee` write target let a command
overwrite a project `.env` or `config.yaml` without triggering approval,
even though the shell still overwrites the file.
## Related Issue
N/A
## Type of Change
- [x] 🔒 Security fix
## Changes Made
- `tools/approval.py`: add `_WRITE_TARGET_BOUNDARY` (a word-boundary
lookahead) and use it instead of `_COMMAND_TAIL` in the two
project-env/config stream-write patterns ("overwrite project env/config
via tee" and "via redirection"). `_COMMAND_TAIL` is kept and still used
by the `cp`/`mv`/`install` rule, where end-of-line anchoring is the
correct semantics.
- `tests/tools/test_approval.py`: add regression tests for
`> .env extra`, `> .env # note`, `>> config.yaml foo`, and
`tee .env backup` (now flagged), plus `> config.yaml.bak` (must stay
safe — different file).
## How to Test
1. Reproduce: before the fix,
`detect_dangerous_command("echo secret > .env extra")` returns
`(False, None, None)` — the overwrite is not flagged.
2. Apply the fix; the same call now returns the "overwrite project
env/config via redirection" detection.
3. Run `pytest tests/tools/test_approval.py -q` — the new cases pass and
the existing `cp config.yaml backup.yaml` / `config.yaml.bak`
false-positive guards still hold.
## Checklist
### Code
- [x] I've read the Contributing Guide
- [x] My commit messages follow Conventional Commits
- [x] I searched for existing PRs to make sure this isn't a duplicate
- [x] My PR contains only changes related to this fix
- [x] I've run the relevant tests and they pass
- [x] I've added tests for my changes
- [x] I've tested on my platform: macOS 15 (Darwin 25.5)
### Documentation & Housekeeping
- [x] I've updated relevant documentation (README, docs/, docstrings) — or N/A
- [x] I've updated cli-config.yaml.example if I added/changed config keys — or N/A
- [x] I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
- [x] I've considered cross-platform impact (Windows, macOS) — or N/A
- [x] I've updated tool descriptions/schemas if I changed tool behavior — or N/A
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