## Stack
1. Parent PR: #18868 adds MITM hook config and model only.
2. This PR wires runtime enforcement.
3. User facing config follow up: #18240 moves MITM policy into the
PermissionProfile network tree.
## Why
1. After the hook model exists, the proxy needs a separate behavior
change that can be tested at the request path.
2. This PR makes hooked HTTPS hosts require MITM, evaluates inner
requests after CONNECT, mutates headers for matching hooks, and blocks
hooked hosts when no hook matches.
3. It also fixes the activation path so a permission profile with MITM
hook policy starts the managed proxy.
4. Keeping this separate from #18868 lets reviewers focus on runtime
effects, telemetry, and request mutation.
## Summary
1. Store compiled MITM hooks in network proxy state.
2. Require MITM for hooked hosts even when network mode is full.
3. Evaluate inner HTTPS requests against host specific hooks.
4. Apply hook actions by replacing request headers before forwarding.
5. Block hooked hosts when no hook matches and record block telemetry.
6. Treat profile MITM hook policy as managed proxy policy so the proxy
starts when needed.
7. Keep the duplicate authorization header replacement and query
preserving request rebuild in this runtime PR.
8. Add runtime tests and README guidance for hook enforcement.
## Validation
1. Ran the network proxy MITM policy tests.
2. Ran the hooked host CONNECT test.
3. Ran the authorization header replacement test.
4. Ran the core permission profile proxy activation test for MITM hooks.
5. Ran the scoped Clippy fixer for the network proxy crate.
6. Ran the scoped Clippy fixer for the core crate.
## Summary
- Replace Codex-branded network-proxy block responses with concise
reason text
- Mention sandbox policy for local/private network and deny-policy
wording
- Remove “managed” from the proxy-disabled denial detail
## Summary
When network requests were blocked, downstream code often had to infer
ask vs deny from free-form response text. That was brittle and led to
incorrect approval behavior.
This PR fixes the proxy side so blocked decisions are structured and
request metadata survives reliably.
## Description
- Blocked proxy responses now carry consistent structured policy
decision data.
- Request attempt metadata is preserved across proxy env paths
(including ALL_PROXY flows).
- Header stripping was tightened so we still remove unsafe forwarding
headers, but keep metadata needed for policy handling.
- Block messages were clarified (for example, allowlist miss vs explicit
deny).
- Added unified violation log entries so policy failures can be
inspected in one place.
- Added/updated tests for these behaviors.
---------
Co-authored-by: Codex <199175422+chatgpt-codex-connector[bot]@users.noreply.github.com>
## Summary
Add explicit, model-visible network policy decision metadata to blocked
proxy responses/errors.
Introduces a standardized prefix line: `CODEX_NETWORK_POLICY_DECISION
{json}`
and wires it through blocked paths for:
- HTTP requests
- HTTPS CONNECT
- SOCKS5 TCP/UDP denials
## Why
The model should see *why* a request was blocked
(reason/source/protocol/host/port) so it can choose the correct next
action.
## Notes
- This PR is intentionally independent of config-layering/network-rule
runtime integration.
- Focus is blocked decision surface only.
This add a new crate, `codex-network-proxy`, a local network proxy
service used by Codex to enforce fine-grained network policy (domain
allow/deny) and to surface blocked network events for interactive
approvals.
- New crate: `codex-rs/network-proxy/` (`codex-network-proxy` binary +
library)
- Core capabilities:
- HTTP proxy support (including CONNECT tunneling)
- SOCKS5 proxy support (in the later PR)
- policy evaluation (allowed/denied domain lists; denylist wins;
wildcard support)
- small admin API for polling/reload/mode changes
- optional MITM support for HTTPS CONNECT to enforce “limited mode”
method restrictions (later PR)
Will follow up integration with codex in subsequent PRs.
## Testing
- `cd codex-rs && cargo build -p codex-network-proxy`
- `cd codex-rs && cargo run -p codex-network-proxy -- proxy`