- Replace 18-line comment block with 3-line invariant statement
- Trim test docstrings from multi-paragraph to single-line summaries
- Trim assertion messages from 4-line to 2-line mismatch reports
- Replace 5-line WHAT comments in stubs with 1-line WHY comments
- Add ziliangdotme@gmail.com -> ziliangpeng to AUTHOR_MAP
## Summary
The background skill/memory-review fork constructed a child `AIAgent`
without propagating `enabled_toolsets` / `disabled_toolsets` from the
parent. When the parent narrowed its toolset (via `hermes tools
disable` or `config.yaml`), the fork's default `enabled_toolsets=None`
expanded to "all registered tools" — and the fork's outbound request
body sent a wider `tools[]` array than the parent's main-turn request.
Anthropic's prompt-cache key includes the `tools[]` array byte-for-byte,
so this divergence forked the cache lineage on every nudge and forced a
full prefix rewrite. On a captured ~4 hour Claude-via-Hermes session
this cost roughly 4.3 M cache-write tokens — about half of those
attributable to the per-nudge alternation between the main turn's
narrowed `tools[]` and the review fork's wider `tools[]`.
## Goal
Extend the byte-stability invariant established by PR #17276 (which
fixed `system`) to the `tools[]` slot of the request body, so the
review fork's outbound request hits the parent's warmed Anthropic
prefix cache regardless of how the parent's toolset is configured.
## Implementation
Two-line change in `agent/background_review.py`: pass
`enabled_toolsets=getattr(agent, "enabled_toolsets", None)` and the
matching `disabled_toolsets` kwarg into the `AIAgent(...)` call inside
`_spawn_background_review`. Adds an explanatory block comment that
calls out the cache-key dependency and the relationship to PR #17276.
The post-construction runtime whitelist
(`set_thread_tool_whitelist({memory, skills})`) is untouched — it
still gates which tools the model is allowed to *dispatch*. This
change aligns only what the request body *transmits*, not what the
review is allowed to do, so the safety contract from issue #15204
remains intact.
## Testing
- `tests/run_agent/test_background_review_cache_parity.py`: new
`test_review_fork_inherits_parent_toolset_config` asserts the
parent's `enabled_toolsets` and `disabled_toolsets` reach the
review-fork constructor as kwargs.
- `tests/run_agent/test_background_review_toolset_restriction.py`:
the existing `test_background_review_does_not_narrow_toolset_schema`
was inverted (its old "must NOT pass enabled_toolsets" rule was
built on the assumption that the parent always ran with the
registry default — wrong in practice when the parent is narrowed).
Renamed to `test_background_review_matches_parent_toolset_config`
and updated to assert the parent's value propagates verbatim.
- Verified the new positive test fails without the fix and passes
with it.
- Full suite for `test_background_review*`:
```
$ python -m pytest tests/run_agent/test_background_review.py \
tests/run_agent/test_background_review_summary.py \
tests/run_agent/test_background_review_toolset_restriction.py \
tests/run_agent/test_background_review_cache_parity.py -q
18 passed in 1.85s
```
## Scope
- `agent/background_review.py`: 2 added kwargs + explanatory comment.
- Two test files: one new positive test, one inverted existing test.
- No production code paths outside the review fork; no schema changes;
no public-API changes.
Refs: ziliangpeng/hermes-agent#1 (root-cause analysis with wire-level
cache-write measurements). Extends PR #17276's `system`-bytes
invariant to the `tools[]` slot.
- test_background_review_does_not_narrow_toolset_schema: review fork must
NOT pass enabled_toolsets to AIAgent (full parent schema = matching
Anthropic cache key on the 'tools' field).
- test_background_review_installs_thread_local_whitelist: the runtime
whitelist that replaces schema-level narrowing must contain memory +
skills tools and exclude terminal / send_message / delegate_task /
web_search / execute_code.
- test_review_fork_inherits_parent_cached_system_prompt: new test for
PR #17276's first root cause — the fork's _cached_system_prompt must
equal the parent's byte-for-byte.
- test_review_fork_pins_session_start_and_session_id: defensive belt-and-
suspenders for the cached-prompt inheritance.
Inverted the original test_background_review_agent_uses_restricted_toolsets
(which asserted the schema-level narrowing) — that narrowing was the
direct cause of #25322's cache miss, and the runtime whitelist replaces
its safety claim without breaking cache parity.
Refs #25322, #15204, PR #17276.
