Ar9av Session Brain
Builds a searchable topic graph over your agent session history. The output is a sidecar
at ~/.claude/session-brain/ — the vault is never touched.
All the heavy lifting is deterministic Python in the obsidian-wiki CLI. Your only job is to
name the clusters, which takes exactly one turn and requires reading no transcripts.
When to use which skill
| Goal | Skill |
|---|---|
| Build or refresh the graph; survey topics | session-brain (this one) |
| Find and load a specific past session | session-search |
| Distil sessions into permanent vault pages | wiki-history-ingest / claude-history-ingest |
Step 1: Build
obsidian-wiki sessions-build --json
Roughly 3 seconds cold on ~1000 sessions, well under a second incrementally — it re-reads only transcripts whose size or mtime changed. Useful flags:
| Flag | When |
|---|---|
--full |
Ignore all caches and re-read everything |
--mutual |
Tighter, smaller clusters (mutual-kNN edges only) |
--half-life N |
Change the recency half-life (default 90 days) |
--min-sim 0.15 |
Fewer, stronger edges — use if the graph is too dense to read |
--skip name |
Exclude a project. Match is substring-based; pass the bare name, because cache dirs start with - and argparse reads that as a flag |
Report the headline numbers: total sessions, how many have transcripts vs. are history-only, edges, and cluster count.
Step 2: Name the unnamed clusters
obsidian-wiki sessions-clusters --unnamed --json
Each cluster comes with top_terms and exemplars (its three highest-degree sessions, whose
titles are already in graph.json). That is all you need. Do not open transcripts to name a
cluster — the whole design goal is that naming costs one turn regardless of corpus size.
Write a 3–5 word name and a one-sentence summary per cluster, then:
obsidian-wiki sessions-name --from - <<'EOF'
[{"id": 3, "name": "warden telemetry pipeline", "summary": "Building and debugging the redacted telemetry chain."}]
EOF
Names are stored in names.json keyed by the cluster's dominant vocabulary, not its id — so they
survive rebuilds even though cluster ids are positional and shift as the corpus grows. On repeat
runs --unnamed is usually empty and this step is free.
If a cluster's terms are genuinely incoherent, name it honestly ("mixed — short sessions")
rather than inventing a theme.
Step 3: Report the map
Read clusters.json and tell the user:
- Biggest topics — by
size - What's hot — highest
momentum(activity in the last 30 days vs. the 60 before it) - What's gone quiet —
dormant: true(low recency and nothing in 60 days) - Where topics meet —
bridges, the sessions that connect two otherwise separate topics. These are often the most interesting sessions in the graph.
Then offer the visualisation:
open ~/.claude/session-brain/graph.html
Node size is session length, brightness is recency, hollow rings are history-only sessions, and gold borders are bookmarked ones. The time slider and search box filter together.
Notes
- Never write to the vault from this skill. If the user wants session knowledge in the vault,
that is
wiki-history-ingest. - History-only sessions are real. Roughly 40% of a long-lived cache exists only as prompts in
history.jsonl; those get graph nodes and are findable, but can never be loaded. Say so plainly rather than implying they are missing. - The graph is derived data. If it looks wrong,
--fullrebuilds from scratch; nothing is lost.