cc-second-brain

What this skill does

# CC Second Brain

Three-tier memory: **engram (working)** + **Obsidian vault (durable)** + **plugin rules (baseline)**. Full separation-of-concerns in [conventions.md](../../memory/conventions.md) and [topic-key-taxonomy.md](references/topic-key-taxonomy.md).

## Tier routing — decision tree

```
Did work just conclude?
│
├─ Is it a one-off observation, decision, or discovery?
│   └─ YES → engram (tier 1) — mem_save with CC topic_key (see taxonomy)
│
├─ Is it a reusable pattern (used or useful in ≥ 2 repos)?
│   └─ YES → Obsidian (tier 2) — Research/Claude-Code/Patterns/{slug}.md
│            with frontmatter auto_generated: false if user-curated
│
├─ Is it repo-specific durable knowledge?
│   └─ YES → Obsidian (tier 2) — Repositories/{org}/{repo}.md
│            or Decisions/NNNN-title.md for ADRs
│
└─ Is it a rule every consumer-repo Claude should follow?
    └─ YES → plugin rules (tier 3) — memory/rules/cc-always.md
             (only the plugin maintainer edits this)
```

## Engram — tier 1 write pattern

Call `mem_save` with CC topic_key. See [topic-key-taxonomy.md](references/topic-key-taxonomy.md) for full prefix table.

**Required:** `title`, `content` (**What/Why/Where/Learned** format).
**Recommended:** `topic_key` starting with `cc/*`, `type` (decision/bugfix/architecture/discovery/pattern/config/preference), `scope` (project or personal).

**Examples:**

```
mem_save({
  title: "Chose protect-sensitive-files hook for all new setups",
  type: "decision",
  topic_key: "cc/hooks/protect-sensitive-files",
  content: "**What**: Default install on every /cc-setup run\n**Why**: Prevents writes to .env / credentials / keys\n**Where**: memory/rules/cc-always.md\n**Learned**: Hook matcher Write|Edit is correct — don't also match MultiEdit, it inherits"
})
```

## Obsidian — tier 2 write pattern

**Preferred**: use Obsidian MCP tools (`mcp__obsidian__*`) if loaded — they append/update via the Local REST API.

**Fallback**: direct Write tool at vault paths.

**Auto-generated note frontmatter (consolidator only):**

```yaml
---
auto_generated: true
source: engram
topic_key: cc/patterns/{slug}
reinforcement_count: 7
first_seen: 2026-04-09
last_updated: 2026-04-16
tags: [claude-code, pattern, auto]
---
```

**User-curated note frontmatter:**

```yaml
---
title: {short title}
created: {YYYY-MM-DD}
tags: [claude-code, type/pattern]
---
```

**Durability invariant:** notes WITHOUT `auto_generated: true` are user-curated. Consolidator never overwrites them. If you're writing a note on behalf of the user, use `auto_generated: false` explicitly.

## Plugin rules — tier 3 write pattern

`memory/rules/cc-always.md` — user-only (edit via `/cc-memory edit-always`).
`memory/rules/cc-patterns.md` — consolidator-only.
`memory/rules/DRAFT.md` — consolidator-only (conflicts).

Do NOT hand-edit `cc-patterns.md` or `DRAFT.md` — the consolidator owns them.

## Querying the tiers

| Need | Tool |
|---|---|
| "Have we solved this before?" | `mem_search` with cc/ prefix hint → `mem_context` for recent history |
| "What's the current rule for X?" | Read `memory/rules/cc-always.md` and `memory/rules/cc-patterns.md` |
| "What patterns exist for Y?" | Obsidian MCP search or Grep on `Research/Claude-Code/Patterns/` |
| "What does this repo know?" | Read `Repositories/{org}/{repo}.md` first |

## /cc-memory subcommands

| Subcommand | Action |
|---|---|
| `search <query>` | engram `mem_search` scoped to `cc/*` keys |
| `export [--domain ...]` | write human digest to `memory/digests/{date}.md` |
| `consolidate` | run consolidator: engram → Obsidian + cc-patterns.md |
| `edit-always` | open `memory/rules/cc-always.md` |
| `review` | open `memory/rules/DRAFT.md` (conflicts) |
| `status` | show: last consolidation, pattern count, draft count, cc/* observation count |

## MCP tools the consolidator uses (READ-ONLY on engram)

| Tool | Used for |
|---|---|
| `mem_search` | Find cc/* observations |
| `mem_get_observation` | Fetch full content of a match |
| `mem_context` | Recent session context for timing |

**NEVER** used by the consolidator: `mem_save`, `mem_update`, `mem_delete`. Those are Claude-in-session or user-manual operations only.

## Common anti-patterns

- Saving to engram without a topic_key for CC work → consolidator can't group observations → pattern never promotes.
- Writing to `Repositories/{org}/{repo}.md` with `auto_generated: true` when it's actually hand-curated → consolidator will overwrite it later.
- Editing `memory/rules/cc-patterns.md` by hand → consolidator will clobber your edits on next run. Put hand-curation in `cc-always.md`.
- Skipping `mem_session_summary` at end of session → next session starts blind; consolidator has less to work with.