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## Description On requests large enough to trigger compression, the proxy emitted an upstream Anthropic request whose `messages[0]` had `role: "system"`. Anthropic's Messages API rejects any `system` role inside `messages[]`: ``` 400 invalid_request_error: "messages.0: use the top-level 'system' parameter for the initial system prompt" ``` The original request correctly carries its system prompt in the top-level `system` parameter; a compression/transform/pipeline step relocates the harness system block into `messages[0]`, so the request fails outright (intermittent only because it requires a context large enough to compress). This adds a wire-contract guard in the Anthropic forwarder: as the **last** step before sending upstream (after every transform, memory injection, tool sort, and pipeline extension, covering both the Bedrock and direct paths), any stray `role="system"` message is relocated out of `messages[]` and merged back into the top-level `system` parameter. Content order is preserved (existing system first, relocated content after) and block-level `cache_control` survives. The guard is a no-op on the common path (no system-role entry → inputs pass through unchanged). Closes #765 ## Type of Change - [x] Bug fix (non-breaking change that fixes an issue) - [ ] 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 - `headroom/proxy/helpers.py`: new pure helper `relocate_system_messages_to_top_level(messages, system) -> (clean_messages, new_system, changed)` plus `_system_message_to_blocks`. Handles `system` being `None`/`str`/`list`, never drops content, preserves order and content blocks. - `headroom/proxy/handlers/anthropic.py`: invoke the guard just before the byte-faithful forward block; on relocation, update `body["messages"]`/`body["system"]`, mark the body mutated (`system_role_relocated`) so the byte-faithful forwarder re-serializes, and log a warning. - `tests/test_proxy_handler_helpers.py`: 3 unit tests (relocate stray system into top-level, append-to-existing-system order, no-op without a system entry). - `CHANGELOG.md`: Bug Fixes entry. ## Testing - [x] Unit tests pass (`pytest`) - [x] Linting passes (`ruff check .`) - [x] Type checking passes (`mypy headroom`) - [x] New tests added for new functionality - [x] Manual testing performed ### Test Output ```text $ uv run --extra dev python -m pytest tests/test_proxy_handler_helpers.py -q 29 passed in 4.95s # Regression on the forward path (byte-faithful forwarding, system-prompt immutability, cache stability): $ uv run --extra dev python -m pytest tests/test_proxy_handler_helpers.py tests/test_proxy_byte_faithful_forwarding.py tests/test_proxy_system_prompt_immutable.py tests/test_proxy_anthropic_cache_stability.py -q 90 passed, 15 warnings in 29.72s $ uv run ruff check headroom/proxy/helpers.py headroom/proxy/handlers/anthropic.py tests/test_proxy_handler_helpers.py All checks passed! $ uv run ruff format --check ... # 3 files already formatted $ uv run mypy headroom/proxy/helpers.py headroom/proxy/handlers/anthropic.py Success: no issues found in 2 source files ``` ## Test verification (RED → GREEN) The new tests exercise the guard directly and import the new helper at module top, so reverting the production fix makes them fail at collection. **RED — production fix reverted (helper removed):** ```text ImportError while importing test module 'tests/test_proxy_handler_helpers.py'. E ImportError: cannot import name 'relocate_system_messages_to_top_level' from 'headroom.proxy.helpers' =========================== 1 error in 0.41s =============================== ``` **GREEN — production fix applied:** ```text tests/test_proxy_handler_helpers.py ... [100%] ======================= 3 passed, 26 deselected in 1.50s ======================= ``` ## Real Behavior Proof - Environment: Python 3.13, `uv run` in this repo, branch `fix/issue-765`. - Exact command / steps: ran the guard on a body in the exact #765 failure shape — `system: None` and a `role="system"` harness block at `messages[0]`: - Observed result: ```text BEFORE: messages[0].role = system (Anthropic 400 trigger) changed = True AFTER roles = ['user', 'assistant'] system param = [{"type": "text", "text": "You are Claude Code. <system-reminder>...</system-reminder>"}] OK: no role=system in messages[]; system content preserved in top-level param ``` The illegal `role="system"` entry is removed from `messages[]` and its content lands in the top-level `system` parameter — exactly the body Anthropic accepts. - Not tested: a full live 250k+-token Claude Code session against the real Anthropic API (needs a large live context + API key); the fix is validated at the request-shaping boundary the 400 is raised on. ## 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 - [x] I have commented my code, particularly in hard-to-understand areas - [x] 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 - [x] I have updated the CHANGELOG.md if applicable ## Additional Notes The guard intentionally fires at the forwarder boundary rather than in any single transform: the issue's captures show the relocation can originate from the compression path, and pipeline extensions / hooks can also mutate `messages` late. Enforcing Anthropic's wire contract once, at the point the body is serialized upstream, fixes the 400 regardless of which step introduced the stray entry and matches the architecture invariant "never produce a `system`-role entry within `messages[]`". --------- Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Co-authored-by: JerrettDavis <mxjerrett@gmail.com>
24 lines
662 B
Python
24 lines
662 B
Python
"""Helpers for optional live Gemini tests."""
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from __future__ import annotations
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from typing import Any
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import pytest
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GEMINI_QUOTA_STATUS = 429
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_GEMINI_QUOTA_MARKERS = (
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"quota",
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"rate limit",
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"rate-limit",
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"too many requests",
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)
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def skip_if_gemini_quota_exhausted(response: Any) -> None:
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"""Skip live Gemini tests when the configured key has no available quota."""
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if getattr(response, "status_code", None) != GEMINI_QUOTA_STATUS:
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return
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body = getattr(response, "text", "") or ""
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if any(marker in body.lower() for marker in _GEMINI_QUOTA_MARKERS):
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pytest.skip("Gemini live API quota/rate limit exhausted")
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