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.
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.
git clone --depth 1 https://github.com/eugeniughelbur/obsidian-second-brainWrote 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.
[](https://agentmods.dev/commands/eugeniughelbur/obsidian-second-brain/obsidian-save)<a href="https://agentmods.dev/commands/eugeniughelbur/obsidian-second-brain/obsidian-save"><img src="https://agentmods.dev/badge/commands/eugeniughelbur/obsidian-second-brain/obsidian-save/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.
<a href="https://agentmods.dev/commands/eugeniughelbur/obsidian-second-brain/obsidian-save"><img src="https://agentmods.dev/badge/commands/eugeniughelbur/obsidian-second-brain/obsidian-save.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00010 | $0.00950 |
| Opus 5 | $0.00005 | $0.00475 |
| Sonnet 5 | $0.00002 | $0.00190 |
| Haiku 4.5 | $0.00001 | $0.00095 |
Grade A, and why
obsidian-save 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 10d 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.
What it actually says
Use the obsidian-second-brain skill. Execute /obsidian-save:
- Read
_CLAUDE.mdfirst if it exists in the vault root - Scan the entire conversation and identify all vault-worthy items: decisions, tasks, people mentioned, projects started, ideas, learnings, deals, mentions/shoutouts, AND content-worthy items (hooks, data points, swipe-file material, research findings)
- Group items by type: people, projects, tasks, decisions, ideas, deals, content
- Spawn parallel subagents - one per group - so all note types are handled simultaneously:
- People agent: search for each person, create or update notes, log interactions
- Projects agent: search for each project, create or update notes. If the conversation was a substantial dev/work session (code written, problems solved, decisions made on a project), also write a dev-log note for it - the same artifact
/obsidian-logproduces - to the logs folder (resolved perreferences/folder-map.md: wiki-stylewiki/logs/, Obsidian-styleDev Logs/), namedYYYY-MM-DD - Project Name.md, and link it from the project's Recent Activity and today's daily note. This is why/obsidian-saveabsorbs/obsidian-log: a full save already captures the work, so you do not need to run both. If a dev-log for this project and date already exists, update it rather than creating a second. - Tasks agent: parse tasks, add to the right kanban columns
- Decisions agent: find relevant project notes, append to Key Decisions sections
- Ideas agent: search Ideas/ for related notes, create or append
- Content agent (if a
social-media/folder exists in the vault): scan for content-worthy items and route them:- Hooks, angles, contrarian takes → append to
social-media/ideas.md(dated bullet) - Specific numbers, stats, reusable data points → append to
social-media/data-points.md(with source) - External posts that hit + why → append to
social-media/swipe-file.md(link + reason) - Research findings, frameworks, methodologies → create
social-media/research/YYYY-MM-DD - topic.md
- Hooks, angles, contrarian takes → append to
- After all agents complete: update today's daily note with links to everything saved
- Report back: a clean list of what was saved and where
Search before creating anything - duplicate notes are vault rot. Propagate every write to boards, daily note, and linked notes. Never create an orphaned note.
The content agent only runs if social-media/ exists in the vault. If it doesn't exist, skip silently - don't create the folder unprompted.
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.
Anti-fabrication: Search exhaustively before claiming any note, person, or file is absent - false absence is the most common failure mode - and never invent facts, entities, or dates (mark unknowns as TBD). See the anti-fabrication and search-completeness hard rules in references/ai-first-rules.md.
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.
- 10d ago First seen · 39 lines · 10 tokens per session scan A ff18c3bc6801
obsidian-save is a command published in the GitHub repository eugeniughelbur/obsidian-second-brain (4,376 stars, last pushed 3d ago), licensed MIT. It adds 10 tokens to every session and 950 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.
Other commands, from other repositories
patterns
Scan recent sessions for recurring patterns and turn them into captures (rules, concept notes, writing seeds).
second-brain-mapping
Map your vault: extract structured metadata from every typed file, surface cross-doc insights, optionally build a knowledge graph.
cierre
A sales call just ended: turn its transcript into the full follow-up (CRM, tasks, email draft, reminder, coaching).
daily-journal
Daily journal interview and entry creator with emotional floor tagging.
deconstruct
First-principles analyst: surface hidden assumptions, find foundational truths, rebuild from scratch.
diagnose
Run a self-check on your AI Brain Starter install (CLAUDE.md, Meta folder, skills, hooks, MCPs).