moltline-mcp

A thin, dependency-free stdio bridge to Moltline Studio's fleet of 14 hosted MCP servers.

Most modern MCP clients can connect to the fleet directly over Streamable HTTP — no install needed (see Direct connection below). This bridge exists for clients that only speak the stdio transport: it proxies newline-delimited JSON-RPC between your client and the hosted server, verbatim, with no telemetry and no dependencies beyond the Python 3.9+ standard library.

• Free tier: no registration, no account, no credentials — connect and call tools immediately.
• Premium tools are unlocked with a Moltline license, presented only as a tool argument (never in URLs or headers). See auth.md.
• Fleet is independently audited: MCPize Verified A on direct endpoints.

The fleet

Server	Tools	What it does
catalog	10	Search and browse the Moltline catalog: 138 skill bundles and all 14 servers.
codereview	7	Code review helpers: diff checklists, smell checks, review summaries.
timeops	5	Time operations: business days, meeting overlap, recurrence, deadlines, SLA due dates.
data	7	Data transforms: parsing, conversion, cleanup, and formatting utilities.
business	8	Small-business operations: invoices, follow-ups, everyday workflows.
creator	8	Content creation: hooks, outlines, captions, repurposing.
educator	7	Education: lesson planning, quizzes, and study aids.
govern	7	Governance checks: policy, compliance, and review gates.
humanizer	5	Text humanizing: tone, clarity, natural rewrites.
merchant	6	Commerce: product copy, listings, storefront helpers.
outbound	8	Outreach: sequences, personalization, reply drafting.
personal	9	Personal productivity: planning, routines, life admin.
research	8	Research: citations, summaries, source organization.
skillmd-lint	6	SKILL.md linting: validate and improve agent skill files.

Machine-readable discovery: api-catalog · per-server card at https://mcp.moltlinestudio.com/<server>/.well-known/mcp/server-card.json · fleet health.

Direct connection (preferred)

If your MCP client supports Streamable HTTP (Claude Desktop, Claude Code, Cursor, and most current clients do), point it straight at the hosted endpoint — nothing to install:

{
  "mcpServers": {
    "moltline-timeops": {
      "type": "http",
      "url": "https://mcp.moltlinestudio.com/timeops"
    }
  }
}

Swap timeops for any slug in the table above.

The stdio bridge (for stdio-only clients)

Install

Run directly (recommended) — the bridge is a single stdlib-only file, so a clone is all you need:

git clone https://github.com/GarphenGate/moltline-mcp.git
python3 moltline-mcp/moltline_mcp.py timeops   # any of the 14 slugs; default: catalog

Docker — see Docker below if you prefer a container.

A PyPI package is planned; until then, use the methods above.

Client configuration

Point your MCP client at the script with an absolute path:

{
  "mcpServers": {
    "moltline-timeops": {
      "command": "python3",
      "args": ["/absolute/path/to/moltline-mcp/moltline_mcp.py", "timeops"]
    }
  }
}

Or run it through Docker (after docker build -t moltline-mcp .):

{
  "mcpServers": {
    "moltline-timeops": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "moltline-mcp", "timeops"]
    }
  }
}

CLI

python3 moltline_mcp.py [server] [--timeout SECONDS] [--list] [--version]

• server — one of the 14 slugs (default catalog); anything else fails fast with the valid list.
• --timeout — per-request timeout in seconds (default 300, or env MOLTLINE_TIMEOUT).
• --list — print the server slugs and exit.
• Env MOLTLINE_BASE_URL — override the fleet base URL (for testing).
• Env MOLTLINE_DEBUG=1 — diagnostic logging on stderr (stdout stays protocol-clean).

Docker

The bridge also runs containerized (stdio in, network egress to the fleet required):

docker build -t moltline-mcp .
docker run -i --rm moltline-mcp timeops   # any of the 14 slugs; default: catalog

See Client configuration for the matching mcpServers entry.

How it works

One process per server connection. Each JSON-RPC message read from stdin is POSTed to https://mcp.moltlinestudio.com/<server>; JSON and SSE-framed responses are relayed back to stdout as newline-delimited JSON. The bridge tracks the server-assigned Mcp-Session-Id and echoes the negotiated MCP-Protocol-Version, per the Streamable HTTP transport spec. It never inspects, stores, or reports your traffic.

Tests

The bridge ships with an offline test suite - no network, no dependencies:

python -m unittest -v

Twenty-two tests cover the parts that actually break in a transport bridge: newline-delimited framing, SSE event splitting (multiple events, multi-line data: payloads, a trailing event with no blank line, comments and named events), session-id capture and reuse, protocol-version negotiation on initialize only, and error relay - a JSON-RPC error document is passed through verbatim, anything else becomes a well-formed -32603. CI runs them on Python 3.9, 3.12 and 3.13, plus a Docker build and container smoke test.

Access and licensing

• Free tier — anonymous. No registration or credentials; all free tools work immediately.
• Premium — unlocked with a Moltline license purchased (human-in-the-loop) at moltlinestudio.com. The license is passed as a tool argument where a premium tool asks for it — never as a bearer header, never in URLs. Details: auth.md.

Links

• Website: https://moltlinestudio.com
• Agent access guide: https://moltlinestudio.com/auth.md
• API catalog: https://moltlinestudio.com/.well-known/api-catalog
• Agent protocol reference (x402, AP2, ACP, UCP, MPP, A2A): https://moltlinestudio.com/protocols.html
• Community: https://community.moltlinestudio.com
• Issues and security reports: see SECURITY.md

License

MIT © 2026 Moltline Studio