obsidian-mcp-server AGENTS.md

Project instructions for building and maintaining an Obsidian MCP server, a service that lets coding agents work with Obsidian notes through the Model Context Protocol.

In plain words
What is it for?
Use it when setting up the server, designing or adding tools, resources, prompts, and services, writing tests, or deciding what to do next.
Why use it?
It gives the agent the server's rules, patterns, available tools, and suggested next steps, reducing guesswork when changing the code.

Instructions file for CodexOpenCode

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 instructions/cyanheads/obsidian-mcp-server/agents-md
Clone the repo
git clone --depth 1 https://github.com/cyanheads/obsidian-mcp-server

Made for: Codex, OpenCode.

Per session 6,725 This file is loaded in full into every session.
When invoked 6,725 The same file — it is already loaded in full.
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 $0.06725 $0.06725
Opus 5 $0.03363 $0.03363
Sonnet 5 $0.01345 $0.01345
Haiku 4.5 $0.00673 $0.00673

Measured yesterday against content hash c702851e6bc6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

obsidian-mcp-server AGENTS.md 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.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

AGENTS.md · 419 lines

How it starts

The opening of the file, as written. The whole thing — 419 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Protocol

Server: obsidian-mcp-server Version: 3.5.0 Framework: @cyanheads/mcp-ts-core ^0.12.3 Engines: Bun ≥1.3.0, Node ≥24.0.0 MCP SDK: @modelcontextprotocol/server ^2.0.0 Zod: ^4.4.3

Read the framework docs first: node_modules/@cyanheads/mcp-ts-core/CLAUDE.md contains the full API reference — builders, Context, error codes, exports, patterns. This file covers server-specific conventions only.


What's Next?

When the user asks what to do next, what's left, or needs direction, suggest relevant options based on the current project state:

  1. Re-run the setup skill — ensures CLAUDE.md, skills, structure, and metadata are populated and up to date with the current codebase
  2. Run the design-mcp-server skill — if the tool/resource surface hasn't been mapped yet, work through domain design
  3. Add tools/resources/prompts — scaffold new definitions using the add-tool, add-app-tool, add-resource, add-prompt skills
  4. Add services — scaffold domain service integrations using the add-service skill
  5. Add tests — scaffold tests for existing definitions using the add-test skill
  6. Field-test definitions — exercise tools/resources/prompts with real inputs using the field-test skill, get a report of issues and pain points
  7. Run devcheck — lint, format, typecheck, and security audit
  8. Run the security-pass skill — audit handlers for MCP-specific security gaps: output injection, scope blast radius, input sinks, tenant isolation
  9. Run the polish-docs-meta skill — finalize README, CHANGELOG, metadata, and agent protocol for shipping
  10. Run the maintenance skill — investigate changelogs, adopt upstream changes, and sync skills after bun update --latest

Tailor suggestions to what's actually missing or stale — don't recite the full list every time.


Core Rules

  • Logic throws, framework catches. Tool/resource handlers are pure — throw on failure, no try/catch. Plain Error is fine; the framework catches, classifies, and formats. Use error factories (notFound(), validationError(), etc.) when the error code matters.
  • Use ctx.log for request-scoped logging. No console calls.
  • Confirm destructive ops with ctx.requestInput. obsidian_delete_note reads ctx.inputs first and return ctx.requestInput(...) when the answer is missing; the handler is re-entered with it. Never await user input mid-handler.
  • All Obsidian access goes through getObsidianService(). No direct fetch() calls to the Local REST API in tools/resources — the service centralizes auth, TLS, timeouts, and ctx.signal propagation.
  • Secrets in env vars only. OBSIDIAN_API_KEY is required; never hardcoded.
  • Command-palette tools are opt-in. obsidian_list_commands and obsidian_execute_command are callable only when OBSIDIAN_ENABLE_COMMANDS=true — Obsidian commands are opaque and can be destructive. When the flag is unset, the entry point wraps both with disabledTool() so they're absent from tools/list (LLM can't invoke) but visible in the operator-facing manifest with a hint to enable them.
  • Path-policy gating goes through PathPolicy. Every path-taking method on ObsidianService calls policy.assertReadable / assertWritable before the upstream HTTP call; obsidian_search_notes post-filters hits via svc.policy.filterReadable. Don't bypass this — OBSIDIAN_READ_PATHS / OBSIDIAN_WRITE_PATHS / OBSIDIAN_READ_ONLY are the single chokepoint, and path_forbidden is declared on every path-taking tool's errors[] contract.
  • Close the loop on issues. When implementing work tracked by a GitHub issue, comment on the issue with what landed and close it. Do both — a comment without a close leaves stale issues open; a close without a comment leaves no record of what shipped. The comment is for future readers — state the concrete changes, not the conversation that produced them.

Read the full file on GitHub · 419 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 · 419 lines · 6,725 tokens per session scan A c702851e6bc6

Subscribe to this mod's changes

obsidian-mcp-server AGENTS.md is an instructions file published in the GitHub repository cyanheads/obsidian-mcp-server (672 stars, last pushed 9d ago), licensed Apache-2.0. It adds 6,725 tokens to every session, about $0.0336 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.

Related

Other instructions, from other repositories

hippocampus CLAUDE.md

Instructions for sturlese/hippocampus, covering layout, frontmatter schema, conventions, answering questions from the vault (read order) and contradictions.

sturlese/hippocampus · 1,570 tokens

hippocampus AGENTS.md

Instructions for sturlese/hippocampus: Read and follow CLAUDE.md in the repository root completely before doing any work. It is the canonical project contract, written for Claude Code as the native host; its vault rules and workflows apply unchanged to Codex.

sturlese/hippocampus · 54 tokens

obsidian-pkm-plugin CLAUDE.md

Instructions for AdrianV101/obsidian-pkm-plugin, covering pkm: 01-projects/obsidian-mcp, claude.md, project overview, commands and install dependencies.

AdrianV101/obsidian-pkm-plugin · 4,656 tokens

Hatchdoor AGENTS.md

AGENTS.md instructions for BatterWorks/Hatchdoor, covering agent instructions, local-only instructions, running dev servers, dev vault fixtures and codegraph.

BatterWorks/Hatchdoor · 1,374 tokens

llm-wiki-agent GEMINI.md

Instructions for SamurAIGPT/llm-wiki-agent, covering llm wiki agent — schema & workflow instructions, how to use, directory layout, page format and ingest workflow.

SamurAIGPT/llm-wiki-agent · 1,590 tokens

obsidian-llm-wiki AGENTS.md

Instructions for green-dalii/obsidian-llm-wiki, covering llm wiki plugin project development standards, 🛡️ six-gate quality closure, gate 1: five-gate automated, gate 2: no side effects and gate 3: no breaking changes.

green-dalii/obsidian-llm-wiki · 7,700 tokens