contextweaver: Instructions file for GitHub Copilot

Context Engine — Agent Instructions

Path-scoped guidance for src/contextweaver/context/. Read before modifying any file here.

Pipeline stage ordering (must not be reordered)

ContextManager.build() executes exactly these 8 stages in order:

1. generate_candidates (candidates.py) — phase + policy filter over event log
2. resolve_dependency_closure (candidates.py) — pull in parent items via parent_id
3. apply_sensitivity_filter (sensitivity.py) — drop/redact by sensitivity level
4. apply_firewall_to_batch (firewall.py) — intercept raw tool_result text
5. score_candidates (scoring.py) — recency + Jaccard token overlap + kind priority + token penalty
6. deduplicate_candidates (dedup.py) — near-duplicate removal
7. select_and_pack (selection.py) — budget-aware token selection
8. render_context (prompt.py) — final prompt assembly

Never reorder these stages. Stages 2 and 4 have hard ordering constraints: dependency closure must run before scoring (ancestors must be scoreable), and the firewall must run before scoring (summaries, not raw text, must be scored).

Firewall invariants

• Raw tool_result text never reaches the prompt. apply_firewall replaces item.text with a summary and stores the raw bytes in ArtifactStore.
• The artifact handle is always f"artifact:{item.id}".
• item.artifact_ref is set on every firewall-processed item.
• Do not bypass apply_firewall_to_batch or move raw text past stage 4.
• See firewall.py and docs/agent-context/invariants.md for full rationale.

Async-first pattern

• The core pipeline runs in _build(), which is synchronous. Both build() (async) and build_sync() (sync) delegate directly to _build().
• build() is async def so callers can await it today; true async I/O will be added if pipeline stages gain await-able steps in the future.
• Do not wrap _build() in asyncio.run() — build_sync() calls it directly.
• The same pattern applies to _build_call_prompt() → build_call_prompt() / build_call_prompt_sync().
• When the manager is async-backed (an async store was passed), the async entry points build() and build_call_prompt() offload the synchronous pipeline body to a worker thread (issue #495) so the awaited store I/O does not block the caller's event loop. _build() holds self._build_lock so concurrent builds on one manager serialize and never race on the thread-unsafe in-memory stores. Keep the lock around the pipeline body if you touch _build(), and offload any new async pipeline entry point the same way.
• The private store loop thread is released via weakref.finalize, not a close() method — do not add ContextManager.close() (or other public lifecycle methods) until the #73/#69 decomposition lands. For deterministic teardown call the finalizer (mgr._store_loop_finalizer()).