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Second Brain Write

CommunityPopular
undefined-ui
second-brain-write

Draft from the vault: outline from concept pages, keep citations to the user's own sources, and surface where their material disagrees. Use this skill when the user wants to write an article, post, essay or newsletter based on what they have collected, or asks what they could write about a topic. Do NOT use for research reports, for writing with no grounding in the vault, or for editing text the user wrote themselves unless asked.

Overview

Publisherundefined-ui
Repositorysecond-brain-os
Skill namesecond-brain-write
Stars
1K
Forks
166
Bundled files
Instructions only
LicenseMIT
Links
Skill sourceRepositoryHomepage
  • Markdown instructions

    A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.

  • Works with any LLM

    AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.

  • Self-contained

    Everything the model needs lives in the instructions — no extra files to sync.

  • Open source

    Published by undefined-ui on GitHub. Read the source before you install it.

Installation

Install the Second Brain Write AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

1

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

  1. Open the app and go to Plugins → Skills.
  2. Choose "Install from GitHub".
  3. Paste the skill folder URL below and confirm.
    https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-write
  4. Enable the skill in any chat where you want it available.
Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.
2

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills
git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git /tmp/second-brain-os
mkdir -p .claude/skills
cp -r /tmp/second-brain-os/skills/second-brain-write .claude/skills/second-brain-write
Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable Second Brain Write in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads Second Brain Write on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so Second Brain Write is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

  • Loaded only when it is needed

    The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.

  • Switch models mid-chat

    Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

Write from the vault

The research is already done, cited and connected. What is left is the argument, and that is the part the user should keep.

Core rule

Assemble structure and evidence. Do not hand back finished prose as if it were theirs.

Workflow

  1. Find the relevant concept pages and say what they collectively argue.
  2. Surface the disagreements. These are where the user has something to say that is not the consensus view, and they are the most useful part of the outline.
  3. Build the outline from pages, each point tied to the page behind it.
  4. Mark the weak points: claims resting on one source, self-reported figures, anything the vault flags as unverified.
  5. Draft only if asked, and say plainly that the phrasing is a first pass to be rewritten in their voice.
  6. Offer to ingest the finished piece back as a source once published.

Output format

Angle: <what this piece argues that the sources do not individually>
Outline:
  1. <point> - [[page]], [[page]]
Weak points: <claims with thin support>
Missing: <what would strengthen it>

Calibration

If every point in the outline comes from one page, this is a summary of that page, not an article. Say so.

Never introduce a specific number or quote that has no source page behind it. That is the failure mode of writing with a model, and in a cited piece it is the one that costs the most.

Frequently asked questions

What does the Second Brain Write AI skill do?

Draft from the vault: outline from concept pages, keep citations to the user's own sources, and surface where their material disagrees. Use this skill when the user wants to write an article, post, essay or newsletter based on what they have collected, or asks what they could write about a topic. Do NOT use for research reports, for writing with no grounding in the vault, or for editing text the user wrote themselves unless asked.

Why use Second Brain Write on TypingMind?

Because you install it once and use it with any model. Second Brain Write is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Second Brain Write in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-write. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Second Brain Write?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Second Brain Write?

As many as you like. As long as a model supports skills, you can use Second Brain Write with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Second Brain Write AI skill free?

Yes. It is published on GitHub by undefined-ui under the MIT license. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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