Obsidian Canvas Boards
AgriciDaniel/claude-obsidian
Creates, inspects and updates Obsidian JSON Canvas boards in a vault, with text, file, link, group and edge nodes, using safe recoverable edits.
Import a large archive into the vault in controlled batches: triage what is worth ingesting, process oldest first, checkpoint after every batch, and keep cost visible.
Install Second Brain Backfill
$ npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install undefined-ui/second-brain-os second-brain-backfill --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/second-brain-backfill .claude/skills/second-brain-backfill && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "second-brain-backfill" agent skill from https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfill into .claude/skills/second-brain-backfill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "second-brain-backfill", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfillType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install undefined-ui/second-brain-os second-brain-backfill --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/second-brain-backfill .agents/skills/second-brain-backfill && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "second-brain-backfill" agent skill from https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfill into .agents/skills/second-brain-backfill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "second-brain-backfill", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install undefined-ui/second-brain-os second-brain-backfill --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/second-brain-backfill .cursor/skills/second-brain-backfill && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "second-brain-backfill" agent skill from https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfill into .cursor/skills/second-brain-backfill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "second-brain-backfill", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/undefined-ui/second-brain-os.git --path skills/second-brain-backfill--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install undefined-ui/second-brain-os second-brain-backfill --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/second-brain-backfill .gemini/skills/second-brain-backfill && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "second-brain-backfill" agent skill from https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfill into .gemini/skills/second-brain-backfill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "second-brain-backfill", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install undefined-ui/second-brain-os second-brain-backfillInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/second-brain-backfill .github/skills/second-brain-backfill && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "second-brain-backfill" agent skill from https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfill into .github/skills/second-brain-backfill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "second-brain-backfill", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install undefined-ui/second-brain-os second-brain-backfill --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/undefined-ui/second-brain-os.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/second-brain-backfill .opencode/skills/second-brain-backfill && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "second-brain-backfill" agent skill from https://github.com/undefined-ui/second-brain-os/tree/main/skills/second-brain-backfill into .opencode/skills/second-brain-backfill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "second-brain-backfill", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
second-brain-backfill- GitHub stars
- 999
- Token cost
- ~504 tokens
- SKILL.md length
- 211 words
- Files
- 1
- Skills in repo
- 23
- Repo updated
- First seen
- Licence
- MIT
At a glance
Import a large archive into the vault in controlled batches: triage what is worth ingesting, process oldest first, checkpoint after every batch, and keep cost visible.
- Works in 6 steps: Triage before ingesting. Read titles and… → Order by date, oldest first. Run it the… → Batch of ten. Ingest following… → …
- The user wants to import years of bookmarks
- SKILL.md covers Core rule, Workflow, Output format and Calibration
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Second Brain Backfill is an agent skill from undefined-ui/second-brain-os. Import a large archive into the vault in controlled batches: triage what is worth ingesting, process oldest first, checkpoint after every batch, and keep cost visible. Use this skill whenever the user wants to import years of bookmarks, an export from another notes app, a downloads folder, a chat history dump, or says "backfill", "bulk import", "process my archive". Do NOT use for ingesting one or a few new sources, which is second-brain-ingest.
Its SKILL.md is about 500 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Knowledge Management, covering Second brain, Note-taking and File organization. The repository describes itself as: An AI second brain that maintains itself. Full guide, starter vault, agent skills and scripts for a self-organizing knowledge base in Claude Code and Obsidian. The licence is MIT.
When your agent uses it
- The user wants to import years of bookmarks
- An export from another notes app
- A downloads folder
- A chat history dump
Example prompts
- “backfill”
- “bulk import”
- “process my archive”
- “/second-brain-backfill”
Workflow steps
6 steps, taken from the first numbered list in SKILL.md.
- Triage before ingesting. Read titles and first paragraphs. Sort into
- Order by date, oldest first. Run it the other way and every old source
- Batch of ten. Ingest following second-brain-ingest.
- Checkpoint: update index.md, append to log.md, commit with the batch
- Stop and wait before the next batch.
- Full lint at the end. Large imports always leave orphans and duplicates.
What it can do on your machine
Read from SKILL.md and the folder at commit d6861cc. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Second Brain Backfill loads about 504 tokens when it runs. Until then it costs about 118 tokens; SKILL.md has 211 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from undefined-ui/second-brain-os at commit d6861cc, republished under its MIT licence (© undefined-ui). 211 words, ~504 tokens.
Download SKILL.mdSave it as
.claude/skills/second-brain-backfill/SKILL.md (or your agent's skills folder).- name
- second-brain-backfill
- description
- Import a large archive into the vault in controlled batches: triage what is worth ingesting, process oldest first, checkpoint after every batch, and keep cost visible. Use this skill whenever the user wants to import years of bookmarks, an export from another notes app, a downloads folder, a chat history dump, or says "backfill", "bulk import", "process my archive". Do NOT use for ingesting one or a few new sources, which is second-brain-ingest.
Backfill an archive
A backfill is where cost and quality both go wrong quietly. Done in the wrong order it also inverts the vault's history, because later sources should update pages that earlier ones created.
Core rule
Oldest first, ten sources per batch, stop for a go-ahead between batches.
Workflow
- Triage before ingesting. Read titles and first paragraphs. Sort into worth-ingesting, keep-in-raw, and delete. Most archives are half dead links and things saved but never opened.
- Order by date, oldest first. Run it the other way and every old source arrives as a contradiction against a page that already has the final answer.
- Batch of ten. Ingest following
second-brain-ingest. - Checkpoint: update
index.md, append tolog.md, commit with the batch range in the message, report counts. - Stop and wait before the next batch.
- Full lint at the end. Large imports always leave orphans and duplicates.
Output format
Batch <n>/<total>: <range>
Ingested: <n> sources -> <n> new pages, <n> updated, <n> links
Skipped: <n> (reason)
Running total: <n> of <n>
Next batch: <what it contains>Calibration
Read every page the first batch produced, all of them. A flaw you let through in batch one is a flaw in four hundred pages by the end, and fixing it afterwards costs more than the original run.
If the archive is over about two hundred sources, propose a filter before starting rather than quoting the full cost.
© undefined-ui, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/second-brain-backfill of undefined-ui/second-brain-os.
Open the folder on GitHubat commit d6861cc
Compare with similar skills
Second Brain Backfill next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Second Brain Backfill this skillundefined-ui/second-brain-os | 999 | — | ~504 | Automated safety check: Pass | MIT | |
| Obsidian Canvas BoardsAgriciDaniel/claude-obsidian | 15k | — | ~1.4k | Automated safety check: Pass | MIT | |
| Icm ArchitectRinDig/icm-architect | 1.8k | — | ~3.2k | Automated safety check: Pass | MIT | |
| Obsidian Bases EditorAgriciDaniel/claude-obsidian | 15k | — | ~1.2k | Automated safety check: Pass | MIT | |
| My LLM WikiMartinLwx/dotfiles | 140 | — | ~2.7k | Automated safety check: Pass | None | |
| Obsidian Knowledge BuilderMichael-OvO/obsidian-knowledge-agent | 205 | — | ~917 | Automated safety check: Pass | MIT |
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Design any process, idea, problem, or body of knowledge into an ICM (Interpretable Context Methodology) workspace — folder structure as agent architecture — or restructure an existing folder, repo…
Obsidian Bases Editor
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Explains, drafts and validates Obsidian Bases .base files, building filters, formulas and table, card or list views, and applying edits only through one inspected transaction.
My LLM Wiki
MartinLwx/dotfiles
Provides access to the user's personal wiki, including notes, research, project documentation, decisions, and archived knowledge.
Obsidian Knowledge Builder
Michael-OvO/obsidian-knowledge-agent
Turns PDFs, slides, syllabi, papers and transcripts into structured, teaching-quality Obsidian notes, matching how much structure is built to how much the material needs.
Second Brain Audit
coleam00/skills
Audit any second brain, notes folder, or agent memory for facts that have quietly stopped being true, then fix the worst one so it stops recurring.
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Related
Categories
Questions about Second Brain Backfill
What does Second Brain Backfill do?
Import a large archive into the vault in controlled batches: triage what is worth ingesting, process oldest first, checkpoint after every batch, and keep cost visible. Second Brain Backfill is an agent skill from undefined-ui/second-brain-os. Import a large archive into the vault in controlled batches: triage what is worth ingesting, process oldest first, checkpoint after every batch, and keep cost visible.
When should I use Second Brain Backfill?
Second Brain Backfill fits situations like: the user wants to import years of bookmarks; an export from another notes app; A downloads folder; A chat history dump.
How do I install Second Brain Backfill in Claude Code?
Run `npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a claude-code`. Or copy the skill folder (skills/second-brain-backfill in undefined-ui/second-brain-os) into .claude/skills/second-brain-backfill in your project. Claude Code loads it when a task matches its description.
How do I install Second Brain Backfill in Codex?
Run `npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a codex`. Or copy the skill folder (skills/second-brain-backfill in undefined-ui/second-brain-os) into .agents/skills/second-brain-backfill in your project. Codex loads it when a task matches its description.
Can I use Second Brain Backfill in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add undefined-ui/second-brain-os --skill second-brain-backfill -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/second-brain-backfill, .gemini/skills/second-brain-backfill, .github/skills/second-brain-backfill and .opencode/skills/second-brain-backfill in your project.
What does Second Brain Backfill need to run?
SKILL.md names no scripts, command-line tools or credentials: Second Brain Backfill is instructions for the agent only.
Does Second Brain Backfill access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Second Brain Backfill safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Second Brain Backfill use?
Second Brain Backfill is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Second Brain Backfill use?
About 504 tokens (SKILL.md is roughly 2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Second Brain Backfill?
Skills that share tags, products or a category with Second Brain Backfill: Obsidian Canvas Boards (AgriciDaniel/claude-obsidian, 15k stars), Icm Architect (RinDig/icm-architect, 1.8k stars), Obsidian Bases Editor (AgriciDaniel/claude-obsidian, 15k stars) and My LLM Wiki (MartinLwx/dotfiles, 140 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Second Brain Backfill?
undefined-ui (a GitHub user) maintains it in undefined-ui/second-brain-os, which has 999 GitHub stars. The repository holds 23 skills in this directory. The repository was last updated on September 29, 2026.
Source: undefined-ui/second-brain-os on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.