| name | brain-hydrate |
| description | Use when users want to bootstrap the brain with existing project knowledge -- reading ADRs, feature specs, UX docs, commit history, and error patterns to seed institutional memory on a project that already has artifacts on disk. Also use for incremental re-hydration after significant work outside the pipeline. Triggers on "hydrate brain", "bootstrap brain", "seed memory", "brain init", "populate brain", "import history". |
Atelier Brain -- Hydrate
This skill reads existing project artifacts and git history, extracts reasoning and decisions, and captures them as brain thoughts with proper types, importance scores, and relations. Run this conversationally -- present the scan results, get approval, then execute.
- Brain configured via `/brain-setup`: `.claude/brain-config.json` (or personal equivalent) present with valid `database_url`, `openrouter_api_key`, and `scope`.
- Brain reachable: `atelier_stats` returns successfully and `brain_enabled: true`.
- Brain MCP tool schemas pre-loaded via ToolSearch (Phase 1 Step 0) before any `atelier_*` / `agent_*` call.
- Pipeline installed: `scout` agent persona present in `.claude/agents/` (required for the Phase 2a fan-out).
- At least one extractable source on disk: ADRs, feature specs, UX docs, `error-patterns.md`, `context-brief.md`, or git history.
- Brain thoughts captured via `agent_capture` (types: `decision`, `rejection`, `preference`, `lesson`, `correction`, `insight`) — no per-run cap.
- Brain relations created via `atelier_relation` (`evolves_from`, `triggered_by`, `supports`, `contradicts`).
- Phase 3 progress and final-summary report on the main thread (counts per source type, breakdown, top themes).
Core Principle
Extract the WHY, never the WHAT. Artifacts on disk are the source of truth for current state. Git is the source of truth for what changed and when. The brain captures reasoning, rejected alternatives, evolution context, and lessons -- the knowledge layer that no file or commit preserves.
Never duplicate artifact content. A decision thought references the ADR it came from but does not restate the ADR. A lesson thought captures the insight, not the code that was fixed.
Phase 1: Scan & Inventory
Before extracting anything, scan the project and present an inventory.
Step 0: Pre-load Brain MCP Tool Schemas
Brain MCP tool schemas are deferred — the first call to any atelier_* or agent_* tool without its schema loaded fails with InputValidationError. Run ToolSearch once before any brain call to load the schemas up front:
ToolSearch query: select:mcp__plugin_atelier-pipeline_atelier-brain__atelier_stats,mcp__plugin_atelier-pipeline_atelier-brain__agent_capture,mcp__plugin_atelier-pipeline_atelier-brain__agent_search,mcp__plugin_atelier-pipeline_atelier-brain__atelier_relation,mcp__plugin_atelier-pipeline_atelier-brain__atelier_browse,mcp__plugin_atelier-pipeline_atelier-brain__atelier_trace
Proceed to Step 1 only after ToolSearch returns.
Step 1: Verify Brain is Live
-
Call atelier_stats to confirm the brain is reachable and brain_enabled: true.
- Not reachable: "Brain is not running. Run
/brain-setup first."
- brain_enabled: false: "Brain is disabled. Enable it with
PUT /api/config { brain_enabled: true } or run /brain-setup."
-
Check current thought count. If thoughts already exist, warn:
"Brain already has [N] thoughts. This hydration will ADD to existing knowledge, not replace it. Duplicate detection will prevent exact re-imports. Proceed?"
Step 2: Scan Artifacts
Scan the project for extractable sources. Use Glob and Bash to inventory:
| Source | How to find | What to count |
|---|
| ADRs | ls docs/adrs/*.md or ls docs/architecture/*.md | Number of ADR files |
| Feature specs | ls docs/product/*.md | Number of spec files |
| UX docs | ls docs/ux/*.md | Number of UX files |
| Error patterns | cat docs/pipeline/error-patterns.md | Number of entries |
| Context briefs | cat docs/pipeline/context-brief.md | Exists or not |
| Git history | git log --oneline --since="6 months ago" (or full history if <500 commits) | Number of significant commits |
Step 3: Present Inventory
Present the scan results to the user:
Brain Hydration Scan
====================
ADRs: [N] files in docs/adrs/
Feature specs: [N] files in docs/product/
UX docs: [N] files in docs/ux/
Error patterns: [N] entries
Context brief: [exists/none]
Git commits: [N] commits (last 6 months)
Estimated thoughts: [low]-[high]
Estimated relations: [low]-[high]
Ready to hydrate?
The user may exclude sources ("skip git history", "only ADRs") or adjust the time window. Respect their scope.
See scout-fanout.md for the Phase 2a scout fan-out protocol: invocation pattern, scout categories, content format, invocation template, skip conditions, file-count gate, dry-run mode, failure handling, and completeness check.
See extraction.md for the Phase 2b Extract & Capture protocol: Sonnet subagent invocation, failure handling, and extraction rules for each source type (ADRs, feature specs, UX docs, error patterns, context brief, and git history).
Phase 3: Progress & Summary
The Sonnet subagent produces a progress report per source type. Eva reads this output and presents the summary on the main thread.
During Extraction
The Sonnet subagent reports progress after each source type:
[ADRs] Captured 12 decisions, 5 rejections, 3 insights. Created 4 relations.
[Specs] Captured 8 decisions, 3 preferences. Created 6 cross-references to ADR thoughts.
[UX] Captured 4 decisions, 2 preferences.
[Error patterns] Captured 7 lessons.
[Git history] Scanned 187 commits, captured 11 significant insights/lessons.
Final Summary
After all sources are processed, call atelier_stats and present:
Brain Hydration Complete
========================
Thoughts captured: [N] (was [M] before hydration)
Relations created: [R]
Breakdown:
decisions: [n]
rejections: [n]
preferences: [n]
lessons: [n]
corrections: [n]
insights: [n]
Top themes (by thought density):
1. [theme] — [count] thoughts
2. [theme] — [count] thoughts
3. [theme] — [count] thoughts
The brain now has institutional memory of your project's
decisions, rejected alternatives, lessons learned, and
user preferences. Agents will surface this context
automatically during pipeline runs.
Incremental Re-Hydration
If the user runs /brain-hydrate on a project that was previously hydrated:
- The scan phase is identical.
- The Sonnet subagent performs dedup before each capture by calling
agent_search with the candidate thought text (threshold 0.85):
- Match found (>0.85 similarity): Skip — this knowledge is already in the brain. Log: "Skipped (already captured): [summary]"
- Partial match (0.7-0.85): Capture as a new thought and create an
evolves_from relation to the existing thought.
- No match (<0.7): Capture normally.
- The Sonnet subagent reports skip count in its progress output: "Skipped [N] thoughts already in brain."
If all candidates are already captured, the Sonnet subagent completes normally with captured=0 and reports the full skip count. Eva presents this in the Phase 3 summary.
This makes re-hydration safe to run multiple times. The brain's write-time conflict detection provides a second safety net.
Scope Controls
The user can narrow scope at any point:
| User says | Behavior |
|---|
| "only ADRs" | Skip all other sources |
| "skip git history" | Process artifacts only |
| "since January" | Adjust git log window |
| "just docs/product/feature-x.md" | Single-file extraction |
| "dry run" | Scan and show what WOULD be captured, but don't write |
Guardrails
These rules are mandatory:
-
Never capture artifact content verbatim. The thought must be a synthesized reasoning statement, not a copy-paste. If you find yourself capturing more than 2 sentences from a single source paragraph, you're copying, not synthesizing.
-
Never capture code. No function signatures, no SQL schemas, no config snippets. The brain stores reasoning about code decisions, not the code itself.
-
Never overwrite existing thoughts. Hydration is additive. If the brain already has thoughts, hydration adds to them. It never deletes or modifies existing thoughts.
-
Respect the write-time conflict detection. If agent_capture returns a conflict warning (duplicate or candidate), log it and move on. Do not force-write.
-
Run to completion. Hydration has no per-run cap. Extract every extractable thought from the collected scout content. Dedup via agent_search (0.85 threshold) handles re-runs safely — already-captured thoughts are skipped automatically.
-
Always verify at the end. Call atelier_stats after hydration to confirm thought count increased as expected.
-
Use the correct scope format for agent_capture. agent_capture takes scope as an array of dot-separated ltree strings, e.g. ["pipeline.adr-0006", "project.atelier"] — not a bare string. Each array element is one ltree path; segments are dot-separated (org.product.feature). Labels may contain ASCII letters (case-sensitive), digits, underscores, and hyphens (hyphens require PostgreSQL >= 16 / ltree 1.2). Do NOT use PostgreSQL brace syntax ({a,b}) — that is the wire format, not the input format.
agent_search and atelier_browse take scope as a bare string (a single ltree path), not an array. Pass "pipeline.adr-0006", not ["pipeline.adr-0006"].
Important Notes
- This skill is conversational. Present the scan, get approval, then execute. Do not auto-run extraction without user confirmation.
- First hydration on a new project is the primary use case. Incremental re-hydration is the secondary use case for catching up after work done outside the pipeline.
- Quality over quantity. 30 high-signal thoughts are worth more than 200 noisy ones. When in doubt, skip the extraction — the brain should be a curated reasoning ledger, not a dump.
- The user can abort at any time. Thoughts already captured remain (they're individually valid). The brain is append-only — partial hydration is fine.
Model Assignment
| Component | Model | Rationale |
|---|
| Phase 1 (scan) | opus (main thread) | Lightweight, conversational -- just Glob, shell inventory, stats |
| Phase 2a (scouts) | haiku (scout subagent — pinned via frontmatter) | File reading only, no reasoning needed |
| Phase 2b (extraction) | sonnet (subagent) | Synthesis quality sufficient for structured extraction rules |
| Phase 3 (summary) | opus (main thread) | Format and present results |
Scouts are invoked as Agent(subagent_type: "scout") with no model parameter; per ADR-0048 the model pinning (claude-haiku-4-5-20251001) is owned by the scout frontmatter at source/{claude,cursor}/agents/scout.frontmatter.yml. The Phase 2b extraction subagent (which calls agent_capture directly per ADR-0027) is invoked as Agent(model: "sonnet") and is intentionally distinct from the post-scout synthesis subagent registered by ADR-0048 — synthesis is read-only filter/rank/trim and cannot call agent_capture.
