obsidian-wiki is a framework that helps AI agents build and maintain an interconnected knowledge base from text-based material in an Obsidian vault. It is for people who want their agents to remember discoveries, connect related information, and answer questions with wiki-link citations. Catalogue add-ons provide the agent skills, instructions, agents, and configuration used to create and maintain these wikis.
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.
npx skills add Ar9av/obsidian-wiki --skill code-understandgit clone --depth 1 https://github.com/Ar9av/obsidian-wikiWrote 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/skills/ar9av/obsidian-wiki/code-understand)<a href="https://agentmods.dev/skills/ar9av/obsidian-wiki/code-understand"><img src="https://agentmods.dev/badge/skills/ar9av/obsidian-wiki/code-understand/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/skills/ar9av/obsidian-wiki/code-understand"><img src="https://agentmods.dev/badge/skills/ar9av/obsidian-wiki/code-understand.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00055 | $0.01086 |
| Opus 5.5 | $0.00022 | $0.00434 |
| Sonnet 5.5 | $0.00011 | $0.00217 |
| Haiku 4.5 | $0.00006 | $0.00109 |
Grade A, and why
code-understand 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.
How it starts
The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Code Understand — On-Demand Architecture Focus Map
You are about to work in a codebase you don't fully know yet. Instead of grepping around or
reading files at random, ask the local extractor for a focus map: the ranked symbols the
architecture hangs on, each with a file:line citation and evidence type. Read only what it
points at — this is a map, not a substitute for reading the actual code it cites.
When to reach for this
- Before editing an unfamiliar module — see what calls it and what it calls before changing its shape.
- The user asks "how does X work", "what's the impact of changing Y", "who else uses this function" for a codebase, not the wiki.
- You're about to do a large refactor and want a ranked list of load-bearing files instead of reading the whole tree.
- You already have a diff or a set of changed files and want to know their blast radius before finishing the change.
Not for: summarizing what a project does for the wiki (that's wiki-update Step 3b, which
calls this same command as part of a bigger sync flow) — use this skill directly only when you
need the focus map for your own immediate work, not to persist knowledge.
Running it
obsidian-wiki code-understand --project <dir> [--backend auto|builtin|codegraph] \
[--changed <file>...] [--since <sha>] [--max-symbols N] [--pretty]
--project— defaults to the current directory.- No
--changed/--since— seeds from every tracked file (full-project scan). --changed <file>(repeatable) — seed from specific files you already know are relevant (e.g. files in the diff you're about to make).--since <sha>— seed from everything changed since a git ref (e.g.--since HEAD~5or a base branch).--backend—auto(default) uses CodeGraph when installed, falls back to the builtin extractor otherwise; forcebuiltinfor the dependency-free path, orcodegraphto require the enhanced backend (fails loudly if it's not installed rather than silently degrading).--max-symbols— cap the focus map size (default 50); keep this small for a quick orientation pass, raise it for a thorough one.
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.
- 9d ago Changed · -9 lines · -120 tokens per session 83e0031dee52
- 1mo ago Changed 28fff0aaa027
- 1mo ago First seen · 91 lines · 175 tokens per session scan A 3d37f30d1ca4
code-understand is a skill published in the GitHub repository Ar9av/obsidian-wiki (3,576 stars, last pushed 3d ago), licensed MIT. It adds 55 tokens to every session and 1,086 once invoked, about $0.0002 per session on Opus 5.5. 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 skills, from other repositories
llm-wiki
Maintain a personal team knowledge base using the LLM Wiki pattern — incremental ingest, query, and lint operations on a layered wiki architecture.
llmwiki
Build and use a persistent, citation-traceable knowledge wiki from documents, research papers, notes, or project documentation. Use for llmwiki projects, retrieving reusable evidence for an agent task, or compiling a corpus for repeated questions. A one-off file read or live web search does not need a wiki.
llm-wiki
Build and maintain a persistent, interlinked Obsidian-compatible markdown wiki using Karpathy's LLM Wiki pattern. Extension-backed with auto-generated metadata, guardrails, and 14 custom tools (+3 opt-in agent-trajectory tools).
api-errors
McpError constructor, JsonRpcErrorCode reference, and error handling patterns for @cyanheads/mcp-ts-core. Use when looking up error codes, understanding where errors should be thrown vs. caught, or using ErrorHandler.tryCatch in services.
report-issue-framework
File a bug or feature request against @cyanheads/mcp-ts-core when you hit a framework issue. Use when a builder, utility, context method, or config behaves contrary to the documented API — not for server-specific application bugs.
report-issue-local
File a bug or feature request against this MCP server's own repo. Use for server-specific issues — tool logic, service integrations, config problems, or domain bugs that aren't caused by the framework.