Open second brain

Skill itechmeat/open-second-brain/skills/open-second-brain

Use Open Second Brain to read, write, and maintain an agent-owned second brain in an Obsidian-compatible Markdown vault. The agent owns one top-level directory (`Brain/`). User-authored notes live wherever the operator names them and are read-only inputs when listed in `notes.read_paths`.From its SKILL.md

Install

npx -y skills add itechmeat/open-second-brain --skill open-second-brain

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

SKILL.md

3.8 KB, as published. Nobody here has run it

Open Second Brain

Use this skill when a user asks an agent to use, configure, inspect, or maintain Open Second Brain.

Layout

Open Second Brain owns one top-level directory in the vault: Brain/. Everything the agent generates on its own lives under it. The exception is the note-lifecycle family (brain_note_lifecycle, brain_scaffold_stub), which acts on a user-note path the caller names and can move a note to a second top-level directory, Archive/.

Brain/ - agent-writable observing memory. Taste signals, accreted preferences (unconfirmed → confirmed → retired), evidence log, snapshots. Operations go through MCP tools brain_feedback, brain_apply_evidence, brain_dream, brain_brief, brain_query, brain_doctor - see the brain-memory skill for the calling protocol. CLI counterparts: o2b brain *.
User-authored notes - the operator's daily journal, weekly notes, project notes, etc. Folder names are operator-chosen. The agent reads these paths only when they appear under notes.read_paths in Brain/_brain.yaml; the agent never writes to them.

Core principles

Treat the vault as user-owned durable knowledge.
Write only into Brain/. Never write to user-authored note folders.
Keep raw operational evidence separate from synthesized knowledge: per-event records go to Brain/log/, preferences live in Brain/preferences/.
Never write secrets, tokens, passwords, private keys, or credential-bearing connection strings.
Prefer deterministic CLI commands (o2b brain ..., o2b doctor, o2b status) over guessing file paths.

Default workflow

Check whether Open Second Brain is configured: o2b status or second_brain_status MCP tool.
Read the machine-local config if available (vault path, agent identity, timezone).
Read the vault-local operating manual Brain/_BRAIN.md - this is the per-vault contract for agents.
Record taste signals as they arrive in dialogue via brain_feedback (see the brain-memory skill).
After producing a durable artifact, check applicable preferences and record evidence via brain_apply_evidence (see the brain-memory skill).
For read access to vault pages by title, use second_brain_query.

Search surfaces

Name the surface a question is shaped for, and route to it explicitly:

Generic recall - brain_search runs hybrid keyword + semantic search over raw chunks. Use it for open-ended, topical, or exploratory questions.
Summary surface - for a question that targets a specific source or an artifact kind (a summary, digest, or other declared schema.page_types type), reach for the summary surface: search by source or filter by artifact kind rather than running a generic search over raw chunks. brain_search detects this structurally and returns surface: "summary" on the response as an advisory route hint; a source-targeted query uses a source:<path> token and an artifact-kind query uses a kind:<type>/type:<type> token whose value is a declared page type. The hint never changes ranking - it names the intended surface so the agent asks the right way.

Safety

If a write operation might affect anything outside the Brain/ directory, ask for explicit confirmation. When in doubt, prefer Brain/.