learn

An end-to-end command for turning a source into linked, checked notes in a personal research vault.

In plain words
What is it for?
Use it to extract claims from papers or other sources, connect them to existing notes, audit the links, archive the source, and print a summary.
Why use it?
It removes the need to run separate extraction, linking, checking, and archiving steps by hand.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/letrplb/second-brain/learn
Any agent
npx skills add letrplB/second-brain --skill learn
Clone the repo
git clone --depth 1 https://github.com/letrplB/second-brain

Made for: Claude Code, Codex.

Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,102 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00038 $0.01102
Opus 5 $0.00019 $0.00551
Sonnet 5 $0.00008 $0.00220
Haiku 4.5 $0.00004 $0.00110

Measured yesterday against content hash 6f313e52c976, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

learn scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/learn/SKILL.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/learn

Intent. End-to-end ingestion. The user-facing composite for "learn this source properly."

What it does (default mode)

Sequential, all inline:

  1. /extract <source>. Atomic claim notes written to notes/claims/. Paper note created in notes/papers/.
  2. For each new claim, /connect <claim>. Sequential pass. Forward + backward links + MOC membership.
  3. For each new claim, /audit <claim> (quick mode). Schema + link check. Skip cold-read in this loop.
  4. Move source. From inbox/<source> to archive/<YYYY-MM-DD>-<source-slug>/<source>. Untouched copy preserved.
  5. Print summary. Claims created, links added, MOCs touched, audit issues, archive path.

If extraction returns 0 claims, stop after step 1 and report.

Deep mode (--deep)

For papers and other dense sources where parallelism helps and the model genuinely needs full audit including cold-read.

  1. /extract <source>. Same as above — inline; the lead does extraction.
  2. Spawn one subagent per new claim. Each subagent does:
    • /connect <its-claim> (full forward + backward + MOC)
    • /audit <its-claim> --mode=full (schema + link + cold-read) Each subagent is fresh-context for its own claim. One claim, one subagent, end-to-endnot one subagent per phase.
  3. Lead waits for all subagents. Collects their summaries.
  4. Cross-connect pass (lead, inline). Walk the new claim set; for each claim, check whether it should link to another new claim whose note didn't exist when its sibling's connect ran. Add missed sibling links.
  5. Move source, print summary.

Subagent count cap: N (claims) × 1. Hard cap of 16 concurrent (Task tool platform limit). If extraction returned >16 claims, queue: spawn first 16, wait for all, then spawn next batch.

When to use which mode

Source class Mode
Tweet, single-paragraph note default. Often 0–1 claim; sequential is fine.
Blog essay (≤2K words) default. 3–8 claims; sequential takes < a minute.
Long essay / chapter (~3–8K words) default unless user wants thorough audit.
Paper (peer-reviewed, dense) --deep recommended.
Anything where the user said "thorough" or "deep" --deep.

Read the full file on GitHub · 98 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 98 lines · 38 tokens per session scan A 6f313e52c976

Subscribe to this mod's changes

learn is a skill published in the GitHub repository letrplB/second-brain (1 stars, last pushed 3mo ago), licensed MIT. It adds 38 tokens to every session and 1,102 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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