obsidian-learn

obsidian-learn is a command for Claude Code from eugeniughelbur/obsidian-second-brain. It costs 20 tokens per session (1,179 once invoked), scanned A, original, MIT.

A command for reviewing an Obsidian vault, a folder of linked notes, to find lessons, decisions, patterns, and mistakes. It can identify knowledge that is stale or replaced.

In plain words
What is it for?
Use it to review recent or all vault learnings, collect lessons from daily notes and development logs, and compare decisions with their outcomes. It can also surface recurring patterns and remove superseded knowledge.
Why use it?
It helps keep accumulated notes useful instead of letting outdated advice and repeated discoveries build up unnoticed.

Command for Claude Code

Written for Claude Code: $ARGUMENTS substitution. Also seen: mentions subagents.

Part of the obsidian-second-brain plugin — 1 skill, 47 commands, 3 hooks shipped together

Good fit Use it to review recent or all vault learnings, collect lessons from daily notes and development logs, and compare decisions with their outcomes. It can also surface recurring patterns and remove superseded knowledge.

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Install with agentmods
npx agentmods add commands/eugeniughelbur/obsidian-second-brain/obsidian-learn
About the project

obsidian-second-brain turns an Obsidian vault into persistent, searchable memory for Claude Code and other command-line coding agents, storing knowledge as linked Markdown notes. It is for developers, founders, writers, and researchers who want agents to retain project context across sessions. Its catalogue entries provide commands, hooks, a plugin, a skill, and instructions for capturing, finding, and maintaining that memory.

eugeniughelbur/obsidian-second-brain · 4,364 stars · on GitHub · eugeniughelbur.github.io

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.

Clone the repo
git clone --depth 1 https://github.com/eugeniughelbur/obsidian-second-brain

Made for: Claude Code.

Or install obsidian-second-brain, the plugin that ships this one along with the rest of its 1 skill, 47 commands, 3 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for obsidian-learn

README.md
[![agentmods](https://agentmods.dev/badge/commands/eugeniughelbur/obsidian-second-brain/obsidian-learn/github.svg)](https://agentmods.dev/commands/eugeniughelbur/obsidian-second-brain/obsidian-learn)
Your own site
<a href="https://agentmods.dev/commands/eugeniughelbur/obsidian-second-brain/obsidian-learn"><img src="https://agentmods.dev/badge/commands/eugeniughelbur/obsidian-second-brain/obsidian-learn/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for obsidian-learn

Your own site · 80×15
<a href="https://agentmods.dev/commands/eugeniughelbur/obsidian-second-brain/obsidian-learn"><img src="https://agentmods.dev/badge/commands/eugeniughelbur/obsidian-second-brain/obsidian-learn.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,179 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00020 $0.01179
Opus 5 $0.00010 $0.00589
Sonnet 5 $0.00004 $0.00236
Haiku 4.5 $0.00002 $0.00118

Measured 9d ago against content hash 5d5667d039ac, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

obsidian-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 9d ago.

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.

commands/obsidian-learn.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Use the obsidian-second-brain skill. Execute /obsidian-learn $ARGUMENTS:

The optional argument is a scope: recent (last 30 days, default), all (entire vault), or a topic name. Scope limits the review LIST only - the Stale and Superseded classifications always scan the entire vault, since a 6-months-old learning cannot appear inside a 30-day window.

  1. Read _CLAUDE.md first if it exists in the vault root

  2. Read index.md and recent operation log for vault context (if Logs/ exists: read the last 2-3 Logs/YYYY-MM-DD.md files; otherwise read log.md)

  3. Spawn parallel subagents to gather learnings:

    • Lessons agent: scan all daily notes for "Lesson learned" sections, "What didn't" sections, evening review insights
    • Decisions agent: read all ADRs in the decisions folder (resolved per references/folder-map.md - wiki-style wiki/decisions/, Obsidian-style Knowledge/ with ADR- filename prefix) - extract the rationale and outcome of each
    • Reports agent: read recent emerge/synthesize/connect/challenge reports in the concepts folder (resolved per references/folder-map.md) - the auto-generated pattern reports
    • Mistakes agent: scan dev logs and daily notes for "what didn't work", "wasted time on", "next time", "lesson", phrases indicating learning from failure
    • Wins agent: scan for patterns that worked - "this saved time", "this approach worked", recurring success patterns
  4. For each learning found, classify:

    • Active: still relevant, recurring, reinforced by recent activity
    • Stale: 6+ months old with no recent reinforcement, or contradicted by newer evidence
    • Superseded: explicitly replaced by a newer ADR or pattern
    • Promoted: appeared 3+ times - should become a permanent rule in _CLAUDE.md
  5. Generate the Learnings Report:

    Active Learnings (still applies)

    • List learnings reinforced in the last 90 days
    • Cite the original source and most recent reinforcement

    Stale Learnings (consider archiving)

    • List learnings with no recent reinforcement
    • Suggest: keep, archive, or convert to history note

    Superseded Learnings (already replaced)

    • Old position → New position with ADR reference

    Promotion Candidates (appeared 3+ times)

    • Learnings strong enough to become permanent rules in _CLAUDE.md
    • Suggest exact wording for the operating manual

    Top 5 Lessons of the Period

    • Most impactful learnings ranked by frequency × recency × consequence
  6. Save the report to the concepts folder (resolved per references/folder-map.md) as YYYY-MM-DD - Learnings Review.md (type: learnings-review, schema in references/ai-first-rules.md)

  7. Append to the operation log: if Logs/ exists write **HH:MM** - learn | X active, Y stale, Z superseded, N promotion candidates to Logs/YYYY-MM-DD.md; otherwise append ## [YYYY-MM-DD] learn | X active, Y stale, Z superseded, N promotion candidates to log.md

  8. Update today's daily note with a brief summary

  9. Offer to:

    • Promote candidates to _CLAUDE.md (with user confirmation)
    • Archive stale learnings (with user confirmation)
    • Export top 5 as a shareable markdown for content/journaling

Lessons that aren't reviewed don't compound. This command turns scattered notes into a living rulebook.


AI-first rule: Every note created or updated by this command MUST follow references/ai-first-rules.md - ## For future agent preamble, rich frontmatter (type, date, tags, ai-first: true, plus type-specific fields), recency markers per external claim, mandatory [[wikilinks]] for every person/project/concept referenced, sources preserved verbatim with URLs inline, and confidence levels where applicable. If that path does not resolve from your working directory, search upward for it; if you still cannot read it, say so before writing rather than producing a note that silently skips the rule. The vault is for future agent retrieval - not human reading.

Read the full file on GitHub · 66 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. 9d ago First seen · 66 lines · 20 tokens per session scan A 5d5667d039ac

Subscribe to this mod's changes

obsidian-learn is a command published in the GitHub repository eugeniughelbur/obsidian-second-brain (4,364 stars, last pushed 2d ago), licensed MIT. It adds 20 tokens to every session and 1,179 once invoked, about $0.0001 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 2026-08-30.