reviewer-summarize-subsystems

name	reviewer_summarize-subsystems
description	Precompute concise per-subsystem summaries (GraphRAG community summaries) over the base code index, so ask / PR-walkthrough get a cheap high-level prior. Use when the user asks to build/refresh subsystem summaries ("просуммируй подсистемы", "построй обзоры модулей", "summarize subsystems"). Requires a built base index + the reviewer MCP server.

Summarize subsystems (community summaries)

Cluster the base code graph into subsystems (by module path) and write a short, grounded summary for each, persisted for ask / PR-walkthrough to use as a cheap high-level prior. This skill reads code and writes summaries to the reviewer store; it does NOT modify code or post to GitHub.

Always write summaries and answer the user in Russian (the project language), regardless of this file's language. Tool calls, code identifiers and path:line stay verbatim.

Tools

Plus list_subsystem_clusters, index_subsystem_summary and prune_subsystem_summaries (reviewer MCP), and the harness Read.

Pipeline

1. Resolve repo/branch.

2. List clusters. Call list_subsystem_clusters(repo, branch). Empty / note about an empty index → tell the user (in Russian) to run /reviewer_sync-codebase first, then stop. The response carries depth (the applied cluster depth), depth_source (env | .review.yml | arg), deferred (stale clusters held back this pass under the cost cap, env SUMMARY_REBUILD_CAP), orphans (stored summaries whose cluster_key is no longer a current cluster), and the (already cap-capped) clusters.

3. Preflight — echo the applied depth and ask for confirmation (gate the run). BEFORE summarizing, show the user (in Russian):

   • the applied depth and where it came from (depth_source: env SUMMARY_CLUSTER_DEPTH, the repo's .review.yml, or an explicit arg);
   • how many clusters there are and at what path level — e.g. «depth=2 → 15 кластеров уровня reviewer/index» — sampling a few cluster_keys from clusters;
   • how many are stale vs fresh, plus deferred (held back by the cap).
   • If orphans > 0, warn: the depth changed or modules were removed, so N summaries are orphaned; a full (uncapped) pass will rebuild and prune them.
   • State the invariant explicitly: cluster_key depends on depth, so changing depth triggers a full rebuild of every summary (old-depth summaries orphan and get pruned). Then ask the user to confirm before running. If they decline, stop without summarizing or pruning.

4. Choose the summary model (only if any cluster is stale == true). A subsystem summary is a coarse, high-level prior — a small/cheap model is appropriate, and reviewing on an expensive model burns tokens. Ask the user which model tier to use for writing summaries, defaulting to a cheap tier (e.g. Haiku/Sonnet/Fable). Remember the choice for this run. If nothing is stale, skip this step (nothing to generate).

5. Summarize only STALE clusters. For each cluster with stale == true (fresh ones are already up to date — skip them, this keeps the pass incremental and cheap):

   • Where your harness supports per-subagent model override, dispatch a subagent on the chosen model to read a few representative files (from files / top_symbols) and return {title, summary} (Russian, grounded — see Grounding below); the orchestrator then persists it. Where override is unavailable, write the summary inline on the session model and note this in the report. Either way:
     • title — one line: what this subsystem is.
     • summary — a compact paragraph: what it does, its key symbols (from top_symbols) and invariants. No path:line required; it is a high-level prior.
   • Persist: index_subsystem_summary(repo, branch, cluster_key, title, summary, source_hash) — pass back the cluster's own source_hash from step 2.

6. Prune orphaned summaries (only on a full pass). If the pass was full — deferred == 0 and you did NOT pass an explicit depth/cap override (so clusters covered every current cluster) — call prune_subsystem_summaries(repo, branch) to delete summaries whose cluster_key is no longer a current cluster (orphaned by a depth change or removed modules). On a partial pass (deferred > 0) skip pruning — deferred clusters are not orphans — and say so in the report (mirrors sync_board --limit).

6.5. Backfill summary embeddings (every pass). Call backfill_summary_embeddings(repo, branch) so any summaries still missing an embedding (older summaries written before vectorization, or where a prior pass's Voyage call failed) become searchable by proximity. It embeds from stored title+summary (no LLM), is idempotent (a warm corpus embeds nothing), and is fail-soft. Mention the embedded count in the report.

7. Report (Russian). The applied depth + depth_source; how many clusters summarized vs skipped-as-fresh vs deferred by the cap (deferred from step 2 — never silently truncate); how many summaries were pruned (step 6), or that pruning was skipped on a partial pass; how many embeddings were backfilled (embedded from step 6.5). If summaries were written inline (no model override), say so.

Grounding (hard rule)

Every summary must reflect real code you read. If a cluster is unclear, say so briefly rather than guessing.

Notes

• Precondition: base index built (reviewer index). Re-running is incremental: unchanged subsystems (matching source_hash) are skipped.
• Read-only on code and GitHub; only writes summaries to the reviewer store.