YunoHost MCP

yunohost-mcp

Secure MCP server for YunoHost: Nostr-authenticated, policy-controlled, auditable administration, diagnostics, and _ynh package development for AI clients (Codex, Claude, OpenCode, ChatGPT-compatible MCP clients).

See PLAN.md for the full design and phased roadmap, and PHASE0_INVESTIGATION.md for how it maps onto YunoHost's actual Python API.

Running the server

yunohost-mcp --transport stdio   # local development, fully trusted (no NIP-98 handshake)

yunohost-mcp --transport http --host 127.0.0.1 --port 8765 # NIP-98-authenticated, remote-capable

By default fake_yunohost is off (real mode) — set YUNOHOST_MCP_FAKE_YUNOHOST=true to run against canned data on a machine without YunoHost installed. See identity.example.toml for identity.toml's shape (pubkey → role mapping; required before any HTTP request can do anything).

Optional local Polypack memory

The server can act as an authenticated façade for a separately installed Polypack MCP service. Set YUNOHOST_MCP_POLYPACK_URL to that service's loopback /mcp/ endpoint; the URL must resolve to 127.0.0.1, ::1, or localhost, and Polypack remains the sole owner of its database. The YunoHost MCP HTTP endpoint is still the only endpoint agents should expose publicly.

The initial integration exposes bounded memory_get, memory_list_contexts, memory_recall, memory_context, memory_thread, memory_store, and memory_feedback tools. Memory reads, writes, and feedback have separate memory.read, memory.write, and memory.feedback scopes; writes are locked and audited, while content is represented in the audit log only by length and hash. Provenance is added by this server, and user metadata cannot forge its reserved _yunohost_* fields. The integration is optional and core YunoHost tools continue to work when Polypack is not installed or not configured.

Installing the client tools

The recommended client-side path is uvx, which creates an isolated environment for the command without requiring users to manage a Python virtual environment:

uvx --from yunohost-mcp-connect yunohost-mcp-connect --help

For a persistent command-line installation, use:

uv tool install yunohost-mcp-connect

The package is also installable with python3 -m pip install yunohost-mcp-connect; that path is mainly useful for development or systems where uv is not available.

Agent-assisted setup

The setup wizard is designed to be run by an AI agent on the user's local machine. It generates a fresh client identity, writes the selected MCP client configuration, and prints the one remaining security-sensitive step: granting the generated npub an appropriate role on the YunoHost server.

uvx --from yunohost-mcp-connect yunohost-mcp-connect setup \

--server https://your-yunohost-domain/mcp \ --client codex \ --format json

Supported clients are codex, claude-desktop, claude-code, gemini, hermes, and opencode. Setup is safe to rerun, refuses conflicting server definitions, backs up an existing configuration before changing it, and never prints the private key. Use --print-only when the agent should display configuration without writing it. After granting the npub and restarting the client, diagnose the connection:

uvx --from yunohost-mcp-connect yunohost-mcp-connect doctor \

--server https://your-yunohost-domain/mcp \ --key-file ~/.config/yunohost-mcp/codex.key \ --format json

Connecting a client: yunohost-mcp-connect

Mainstream MCP clients (Claude Desktop, a plain Codex install, etc.) have no way to sign a NIP-98 Authorization header — that's specific to this server. yunohost-mcp-connect bridges the gap: a small local process that speaks plain MCP over stdio to your actual client, and forwards every request to the remote --transport http server, signed with your own Nostr key.

yunohost-mcp-connect --remote-url https://your-yunohost-domain/mcp --key-file ~/.config/yunohost-mcp/key

• --key-file (or $YUNOHOST_MCP_CLIENT_KEY_FILE) points at a file holding a hex or nsec1... private key — preferred over --key/$YUNOHOST_MCP_CLIENT_KEY, which put the key in argv/environment where other processes on the same machine can read it.
• --generate-key PATH writes a fresh private key to PATH (0600; refuses to overwrite an existing file), prints its npub, and exits without connecting anywhere — the way to get a --key-file in the first place. Use a distinct PATH per client; see "Give each client its own key file" below.
• --delegation-file (or $YUNOHOST_MCP_CLIENT_DELEGATION_FILE) presents a delegation event (PLAN.md Phase 11) alongside your own signature, for a disposable agent identity an owner granted a subset of their access to.
• Point your MCP client's config at this command (not the server directly) — tools/list, tools/call, resources/list, and resources/read are forwarded verbatim; authorization, policy, and audit still happen on the remote server.

Each connector starts its local MCP endpoint independently of the remote YunoHost handshake. If one configured YunoHost instance is offline, that connector stays alive, reports no discovered tools until the instance returns, and retries on later requests; other configured MCP servers can still start and remain usable.

Incident introspection

The server includes bounded, read-only diagnostics for intermittent outages:

• web_logs parses Nginx access/error logs, including HTTP and upstream status.
• journal_query reads allowlisted service, SSH, firewall, kernel, OOM, and systemd journals.
• system_snapshot, service_history, ssh_diagnose, and network_snapshot expose host, restart, access-control, and socket state.
• http_probe tests an HTTP(S) endpoint, while incident_snapshot collects the main evidence for a time window.

Log paths, output limits, command timeouts, and whether private HTTP targets are permitted are configurable with YUNOHOST_MCP_* settings. All of these tools are read-only and enforce bounded output.

Connecting Claude Desktop or Codex

Both point at yunohost-mcp-connect, not at the server directly — the bridge is what signs each request with your Nostr key. Use the full path to yunohost-mcp-connect in whatever environment you installed yunohost-mcp into (e.g. ~/.local/pipx/venvs/yunohost-mcp/bin/yunohost-mcp-connect, or a venv's bin/ directory — which yunohost-mcp-connect after activating it will tell you).

Give each client its own key file. YUNOHOST_MCP_CLIENT_KEY_FILE *is* the identity — whichever key signs a request determines its role and scopes on the server, nothing else. Point two different clients (or two different config files for the same client — a project-local .codex/config.toml shadows ~/.codex/config.toml) at the same key file and the second one silently authenticates as the first, with its exact permissions - no error, nothing to notice. Generate a fresh key per client rather than copying one that already works:

yunohost-mcp-connect --generate-key ~/.config/yunohost-mcp/claude-desktop.key

yunohost-mcp-connect --generate-key ~/.config/yunohost-mcp/codex.key

Each prints the new key's npub - grant it whatever role is appropriate for that specific client (see "Granting a disposable agent identity access" below, or identity.toml directly), not the role you already gave a different one. --generate-key refuses to overwrite a file that already exists.

Claude Desktop (claude_desktop_config.json — Settings → Developer → Edit Config):

{

"mcpServers": { "yunohost-mcp": { "command": "/full/path/to/yunohost-mcp-connect", "env": { "YUNOHOST_MCP_CLIENT_REMOTE_URL": "https://your-yunohost-domain/mcp", "YUNOHOST_MCP_CLIENT_KEY_FILE": "/home/you/.config/yunohost-mcp/claude-desktop.key" } } } }

Codex CLI (~/.codex/config.toml):

[mcp_servers.yunohost-mcp]

command = "/full/path/to/yunohost-mcp-connect"

[mcp_servers.yunohost-mcp.env] YUNOHOST_MCP_CLIENT_REMOTE_URL = "https://your-yunohost-domain/mcp" YUNOHOST_MCP_CLIENT_KEY_FILE = "/home/you/.config/yunohost-mcp/codex.key"

Run yunohost-mcp-connect --key-file once per new key to see its npub (yunohost-mcp-connect: signing as npub1...), then grant that npub whatever role is actually appropriate for that client in identity.toml - not the role you already gave a different one.

For a delegated (disposable) identity instead of your own key, add YUNOHOST_MCP_CLIENT_DELEGATION_FILE pointing at the file yunohost-mcp-delegate produced (see below). Restart the client after editing its config — both read this file once, at startup.

Granting a disposable agent identity access: yunohost-mcp-delegate

An identity.toml entry grants access to one specific pubkey, permanently (until edited). A delegation (PLAN.md Phase 11) is the other way to grant access: an owner signs a short-lived, scoped grant to an agent's own disposable key, without ever adding that key to identity.toml or handing over any private key. yunohost-mcp-delegate is what an owner runs to create one:

yunohost-mcp-delegate --key-file ~/.config/yunohost-mcp/key \

--delegate npub1... \ --remote-url https://your-yunohost-domain/mcp \ --role readonly --ttl 24h \ --out agent-delegation.json

• --delegate is the agent's own pubkey (it must sign its own NIP-98 requests as always — a delegation never replaces that, it only adds standing).
• --remote-url fetches the server's pubkey and this owner's own current scopes automatically — no need to type the server's pubkey by hand, and an over-broad --scope/--role request is flagged (the server can never grant more than the delegator's own current scopes; see auth/delegation.py). Pass --server instead if you'd rather supply the server's pubkey directly.
• --scope/--role (repeatable, combinable) choose what to grant; --ttl (e.g. 24h, 7d) how long — the server rejects anything over 30 days.
• The output is a signed delegation event: a bearer credential once issued. Hand the file to the agent to use with yunohost-mcp-connect --delegation-file agent-delegation.json, over a channel you trust (the same as you'd hand over an API key).
• To take a delegation back before it expires, add its id (printed after signing) to revoked_delegations.toml — this is independent of, and finer-grained than, removing the delegator's own identity.toml entry (which revokes every delegation they've ever issued).

Approving high-risk operations: yunohost-mcp-approve

Some operations (system_upgrade, backup_restore, backup_delete, system_migrate, user_delete, permission changes, firewall changes) require owner co-signature on top of the requester's own confirmation (PLAN.md Phase 13, solo profile - see docs/owner-approval-plan.md in the packaging repo for the full design). The requester's call pauses with a confirmation_id; the configured owner reviews and approves it with yunohost-mcp-approve, signing through their own NIP-46 remote signer app (Amber, nsec.app, ...) - their private key never touches this server or the requesting agent's machine.

DNS publishing, catalogue publication, and package-test lifecycle operations also require owner co-signature. Package-test writes must first use package_test_prepare; the returned short-lived session binds the operation to one requester, candidate source, and app id. Treat package testing as privileged because candidate package scripts execute with YunoHost privileges.

For reverse-proxy deployments, set YUNOHOST_MCP_PUBLIC_BASE_URL to the exact public origin used in NIP-98 signatures (for example https://mcp.example.org). Requests with an unexpected Host header are rejected. Keep the local stdio transport restricte