## Description
Compress Hermes Studio scoped coding-agent passthrough requests in the
generic OpenAI passthrough handler. Hermes can route scoped Claude Code
and Codex traffic through Headroom while preserving its own proxy paths;
this PR keeps Hermes responsible for scoped proxy
authentication/provider adaptation while still applying Headroom
compression to supported chat payloads before forwarding.
The compression remains narrow-scoped:
- Only chat messages with `user` or `assistant` roles are compressed.
- Tool, function, reasoning, and system items are preserved byte-stable.
- Non-dict items in the Responses `input` array are preserved and
spliced back.
## Type of Change
- [ ] Bug fix (non-breaking change that fixes an issue)
- [x] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Performance improvement
- [ ] Code refactoring (no functional changes)
## Changes Made
- Detect `/api/codex-proxy/.../v1/responses` paths and compress
supported Responses `input` chat items before forwarding.
- Detect `/api/claude-code-proxy/.../v1/messages` paths and compress
supported Anthropic `messages` payloads before forwarding.
- Preserve bypass, malformed payload, missing-model, tool/function,
reasoning/system, and non-dict passthrough behavior.
- Add regression coverage in
`tests/test_hermes_passthrough_compression.py`.
## Testing
- [x] Unit tests pass (`pytest`)
- [ ] Linting passes (`ruff check .`)
- [ ] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [ ] Manual testing performed
### Test Output
```text
$ python -m pytest tests/test_hermes_passthrough_compression.py -v
test_codex_proxy_preserves_tool_and_function_items PASSED
test_codex_proxy_preserves_nondict_items PASSED
test_codex_proxy_bypass_header_skips_compression PASSED
test_codex_proxy_malformed_input_preserved PASSED
test_codex_proxy_compression_applies_to_chat_messages PASSED
test_claude_proxy_preserves_tool_use_items PASSED
test_claude_proxy_bypass_header_skips_compression PASSED
test_claude_proxy_no_model_forwarded_unchanged PASSED
test_claude_proxy_compression_applies_to_chat_messages PASSED
test_non_hermes_routes_not_affected PASSED
```
## Real Behavior Proof
- Environment: Author-reported local test environment for
`headroom/proxy/handlers/openai.py` and
`tests/test_hermes_passthrough_compression.py`.
- Exact command / steps: `python -m pytest
tests/test_hermes_passthrough_compression.py -v`.
- Observed result: The 10 Hermes passthrough regression tests passed,
covering Codex and Claude scoped proxy routes plus preservation/bypass
cases.
- Not tested: End-to-end Hermes Studio traffic against a live upstream
service is not covered by this PR body evidence.
## Review Readiness
- [x] I have performed a self-review
- [x] This PR is ready for human review
## Checklist
- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] I have updated the CHANGELOG.md if applicable
## Screenshots (if applicable)
N/A.
## Additional Notes
Generated with Claude Code. The unchecked checklist items are not
required for this narrow proxy-handler test change.
---------
Co-authored-by: x1051445024 <你的GitHub注册邮箱>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: JerrettDavis <mxjerrett@gmail.com>
