obsidian-mcp

Read and write an Obsidian vault via MCP (Model Context Protocol), gated by OAuth-issued JWT bearer tokens.

This server pairs with any OAuth 2.1 + PKCE authorization server that can mint JWTs containing aud, iss, sub, scope claims. Two signing modes:

HS256 (default) — shared symmetric key between AS and this server. Use for self-built minimal AS.
RS256 — fetches JWKS automatically via OIDC discovery from <Issuer>/.well-known/openid-configuration. Use with any standard provider: Logto, ZITADEL, Keycloak, Auth0, etc.

See Choosing an AS below for setup guidance.

Architecture

MCP client (Claude.ai, etc.)
    │
    │ ① GET /.well-known/oauth-authorization-server  (RFC 8414)
    │ ② OAuth Authorization Code + PKCE  (against your AS)
    │ ③ Bearer JWT (aud=obsidian, scope=read:obsidian | write:obsidian)
    │
    ▼
obsidian-mcp /mcp
    │  JWT verify (HS256, shared key with AS)
    │  VaultPathResolver — chroot + blacklist
    │  VaultWriteGuard   — whitelist for writes
    │
    ▼
/vault  (mounted directory — local folder, WebDAV sync target, etc.)

MCP tools

| Tool | Scope required | Description | |---|---|---| | list_vault_tree | read:obsidian | Depth-limited directory tree of the vault | | list_files | read:obsidian | Files and subdirs in a directory | | read_file | read:obsidian | File content (UTF-8), with optional byte-range params | | search | read:obsidian | Literal substring search, glob-filterable | | get_metadata | read:obsidian | Size, modified_at, has_frontmatter | | write_file | write:obsidian | Overwrite a whitelisted file | | append_file | write:obsidian | Append to a whitelisted file |

Configuration

All settings are bound from configuration with Vault__, Jwt__, Mcp__OAuthDiscovery__ prefixes (double underscore = nested section). Production values must be injected via env vars.

| Variable | Default | Required | Description | |---|---|---|---| | Vault__Root | /vault | yes | Vault root directory inside the container | | Vault__Blacklist__0 | — | no | Extra path segments to deny (.obsidian, .trash, .git are always denied) | | Vault__WriteWhitelist__0 | — | for write tools | Writable path entries (see below) | | Jwt__Algorithm | HS256 | no | HS256 or RS256 | | Jwt__Issuer | — | yes | Expected iss claim — your AS's issuer URL | | Jwt__Audience | obsidian | no | Expected aud claim | | Jwt__SigningKey__Current | — | HS256 only | HS256 signing key, shared with your AS | | Jwt__SigningKey__Previous | — | no | Previous HS256 key during rotation window | | Mcp__OAuthDiscovery__Issuer | — | yes | /.well-known/oauth-authorization-server issuer field | | Mcp__OAuthDiscovery__AuthorizationEndpoint | — | yes | Your AS's /authorize URL | | Mcp__OAuthDiscovery__TokenEndpoint | — | yes | Your AS's /token URL | | Mcp__OAuthDiscovery__RegistrationEndpoint | — | no | Your AS's /register URL (DCR) | | Mcp__OAuthDiscovery__ResourceUrl | request host | no | RFC 9728 resource identifier for this MCP server | | AuditLog__Directory | /app/logs | no | Directory for audit log files | | ASPNETCORE_ENVIRONMENT | Production | no | Development for verbose logs |

Write whitelist format

Vault__WriteWhitelist__N entries gate every write/append operation:

Ending with / (or \) → prefix match. Example: Notes/ allows any path under Notes/.
Otherwise → exact path match. Example: todo.md allows only that one file.

Always forbidden regardless of whitelist: any path whose filename is AGENTS.md, README.md, or CLAUDE.md (these are common agent-context files; mutating them tends to confuse downstream tooling).

If WriteWhitelist is empty, all writes are denied.

Local development

# 1. Create a test vault
mkdir -p test-vault/Notes
echo "# Test" > test-vault/Notes/test.md

# 2. Set required env vars
export Vault__Root=./test-vault
export Vault__WriteWhitelist__0=Notes/
export Jwt__Issuer=https://your-auth-server.example.com
export Jwt__Audience=obsidian
export Jwt__SigningKey__Current=dev-secret-key-at-least-32-chars-long
export Mcp__OAuthDiscovery__Issuer=https://your-auth-server.example.com
export Mcp__OAuthDiscovery__AuthorizationEndpoint=https://your-auth-server.example.com/authorize
export Mcp__OAuthDiscovery__TokenEndpoint=https://your-auth-server.example.com/token

# 3. Run
dotnet run

# 4. Generate a test JWT (requires dotnet user-jwts)
dotnet user-jwts create \
    --issuer https://your-auth-server.example.com \
    --audience obsidian \
    --name tester \
    --claim sub=tester \
    --claim scope="read:obsidian write:obsidian"

# 5. Test with MCP Inspector
npx @modelcontextprotocol/inspector
# Transport: Streamable HTTP
# URL: http://localhost:5000/mcp
# Bearer Token: <paste JWT from step 4>

Docker

A multi-stage Dockerfile is included. Build locally with:

docker build -t obsidian-mcp .

Run with a mounted vault:

docker run --rm -p 8080:8080 \
  -v /path/to/vault:/vault \
  -e Jwt__Issuer=https://your-auth-server.example.com \
  -e Jwt__SigningKey__Current=$JWT_SIGNING_KEY \
  -e Mcp__OAuthDiscovery__Issuer=https://your-auth-server.example.com \
  -e Mcp__OAuthDiscovery__AuthorizationEndpoint=https://your-auth-server.example.com/authorize \
  -e Mcp__OAuthDiscovery__TokenEndpoint=https://your-auth-server.example.com/token \
  -e Vault__WriteWhitelist__0=Notes/ \
  obsidian-mcp

The included .gitea/workflows/build-image.yml is a Gitea Actions workflow that builds and pushes the image. It expects these repository Variables / Secrets:

vars.REGISTRY — registry hostname (e.g. ghcr.io)
vars.IMAGE_OWNER — registry owner/namespace
secrets.PACKAGES_TOKEN — registry push token

Choosing an AS

Claude.ai chat enforces the full OAuth Authorization Code + PKCE flow against your MCP server's /.well-known/oauth-authorization-server endpoint — there is no bearer-token shortcut. Pick one of these paths:

Hosted (fastest start, recommended for new setups) — RS256 mode:

| Provider | Free tier | Notes | |---|---|---| | Logto Cloud | 5000 MAU | Lightest, ~30 min setup | | ZITADEL Cloud | 25k auths/month | More featureful, slightly heavier docs |

Set Jwt__Algorithm=RS256 and Jwt__Issuer=<your-tenant-issuer-URL>. Public keys are fetched automatically from <Issuer>/.well-known/openid-configuration.

Self-hosted, full-featured — RS256 mode: Keycloak, ZITADEL, Logto, Authentik.

Self-hosted, minimal — HS256 mode: Write your own ~500 LoC AS that issues HS256 JWTs with the right claims. The MCP server's Jwt__SigningKey__Current and the AS's signing key must match.

Required AS features regardless of choice:

OAuth 2.1 + PKCE (RFC 7636)
Dynamic Client Registration (RFC 7591) — so Claude.ai can self-register
resource parameter support (RFC 8707) — for audience-bound tokens
Custom scope support (read:obsidian, write:obsidian)

Running tests

cd obsidian-mcp.Tests
dotnet test

License

MIT

MCP Servers