# Second Brain Query

> >-

- **Type:** Skill
- **Install:** `agentstack add skill-undefined-ui-second-brain-os-second-brain-query`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [undefined-ui](https://agentstack.voostack.com/s/undefined-ui)
- **Installs:** 0
- **Category:** [AI & ML](https://agentstack.voostack.com/c/ai-and-ml)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [undefined-ui](https://github.com/undefined-ui)
- **Source:** https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-query
- **Website:** https://x.com/undefinedKi/status/2068306794116501544

## Install

```sh
agentstack add skill-undefined-ui-second-brain-os-second-brain-query
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Query the vault

A query that quietly falls back on general knowledge is the most damaging thing
this system can do. The owner built the vault so answers would be grounded in
what they actually read, and an answer that blends the model's priors with
their notes is worse than no answer, because it cannot be checked.

## Core rule

Every claim in the answer comes from a page in the vault and names that page.
Anything you know but the vault does not is labelled as outside knowledge or
left out.

## Workflow

1. **Start from `index.md`**, not from a full-text sweep. The index is the map;
   reading it first keeps the context budget for actual pages.
2. **Follow links outward** from the most relevant pages, one hop at a time.
   Stop when new pages stop adding anything.
3. **Answer in plain language**, with `[[page]]` references inline.
4. **Name the gaps.** If the question has three parts and the vault covers two,
   say which one it does not.
5. **Offer the next move** when there is an obvious one: a source worth
   ingesting, a synthesis page worth writing.

## Output format

Plain prose, then:

```
Read: 
Not covered: 
```

## Calibration

Reading too little is the common failure: answering from three pages when the
vault has fifteen relevant ones. Reading everything is the opposite failure and
burns the budget on pages that add nothing.

If the vault has nothing on the topic, say so in one sentence and stop. Do not
pad the answer with general knowledge to avoid an empty result.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [undefined-ui](https://github.com/undefined-ui)
- **Source:** [undefined-ui/second-brain-os](https://github.com/undefined-ui/second-brain-os)
- **License:** MIT
- **Homepage:** https://x.com/undefinedKi/status/2068306794116501544

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-undefined-ui-second-brain-os-second-brain-query
- Seller: https://agentstack.voostack.com/s/undefined-ui
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.