Ask your AI assistant when your preliminary notice and mechanics lien deadlines fall, and get the statute behind every date. This MCP server connects Claude, ChatGPT, Cursor, VS Code and any other MCP client to LienDeadline, the deadline engine for US construction material suppliers. There is nothing to install: add one URL.

Why LienDeadline

Miss a preliminary notice or a lien filing deadline and a supplier can lose its lien rights on the job, and with them the leverage to get paid. The rules change with the state, the project type and who hired you. LienDeadline turns your delivery dates into those deadlines and shows its work.

• Deadlines from delivery dates. Preliminary notice and lien filing deadlines from your first and last delivery and a few yes, no or unknown questions.
• The statute behind every date. Each deadline cites its source, so your team and your counsel can check it.
• Never a guessed date. Missing facts and unsupported project scopes come back as "needs review", with the reason.
• Lien guides for all 50 states and DC. Rule summaries, deadline tables and common questions, with statute citations.
• Safe by design. Supplier discovery and calculations require a caller customer key; completed calculations consume plan allowance. Public guides need no account or key. Nothing sends notices, files liens or makes payments.

Quick start

Connecting to the hosted server and using public guides needs no install, account or key:

https://mcp.liendeadline.com/mcp

The no-authentication connection settings below cover the transport and public guides. Supplier discovery and calculations require the caller's dedicated customer key through the client's approved credential settings. Discovery does not consume calculation allowance; completed calculations do.

| Client | How to add it | | --- | --- | | Claude (web, desktop, mobile) | Open LienDeadline in Claude's Connectors directory and connect it. | | Claude Code | claude mcp add --transport http liendeadline https://mcp.liendeadline.com/mcp | | Cursor | | | VS Code | | | ChatGPT | Open Plugins, select + → Add custom MCP server, paste the URL above and choose No authentication. | | Codex CLI | codex mcp add liendeadline --url https://mcp.liendeadline.com/mcp | | Any MCP client | Streamable HTTP at the URL above. Public guides need no authentication; supplier tools need a customer key. |

Want your agent to ask the right questions too? The LienDeadline agent skill (GitHub) teaches it which facts to collect. The Claude Code plugin adds the skill and this server in one step:

claude plugin marketplace add LienDeadline/skills
claude plugin install liendeadline@liendeadline

The local server needs Node.js 22.22 or newer and serves every tool, including the two customer API tools. It ships npm-shrinkwrap.json, so npx installs the exact dependency versions each release was tested with.

Claude Desktop: download liendeadline-mcp-<version>.mcpb from the latest release and open it.

Claude Code:

claude mcp add liendeadline -- npx -y liendeadline-mcp

Codex CLI:

codex mcp add liendeadline -- npx -y liendeadline-mcp

Cursor, Windsurf and other mcpServers clients:

{
  "mcpServers": {
    "liendeadline": { "command": "npx", "args": ["-y", "liendeadline-mcp"] }
  }
}

VS Code (.vscode/mcp.json):

{
  "servers": {
    "liendeadline": { "type": "stdio", "command": "npx", "args": ["-y", "liendeadline-mcp"] }
  }
}

What you can ask

Try asking:

• "We delivered to a Florida commercial job for a subcontractor from Aug 3 to Sep 10, 2026. No final payment, no termination. When are our notice and lien deadlines?"
• "Same job, but I don't know whether the owner made final payment. What can you tell me?"
• "Walk me through Texas mechanics lien rules for a material supplier and cite the statutes."
• "Which states do you have lien guides for? Show me Georgia's."

Coverage

| What | Where | Needs | | --- | --- | --- | | Supplier discovery and calculations (v3) | Current jurisdiction-specific scope support from get_supplier_questions; start here for the state, project type and hiring relationship | Customer key; discovery uses no calculation allowance; completed calculations consume allowance | | Delivery-event baselines (v2) | Florida and Kansas private projects | Customer key; completed calculations consume allowance | | Lien guides | All 50 states and DC | Nothing | | Invoice-based deadlines | 51 jurisdictions | A customer API key |

The website calculator and v3 tools cover more jurisdictions than the v2 Florida/Kansas baseline. V3 discovery reports the current supported scope and its rule identities; a guide, research approval or state name alone does not establish a calculated date. When a scope or fact needs qualified review, the result explains why. An unavailable reviewed source returns an error with no date.

How it works

1. You ask your AI assistant about a job.
2. The assistant calls LienDeadline's tools over MCP with the state, the dates and your answers.
3. LienDeadline applies that state's rules and returns each deadline with its statute, or "needs review" with the reason.
4. Before showing a supplier deadline, the server checks that the result echoes exactly the facts you sent. A mismatch is reported as an error, never as a date.

Tools

| Tool | What it does | Key | | --- | --- | --- | | calculate_supplier_deadlines | Preliminary notice and lien filing deadlines from delivery dates and yes, no or unknown event answers | Customer | | get_supplier_questions | Whether v3 covers a state, project type and hiring relationship, with its questions, sources and rule versions | Customer | | calculate_supplier_deadlines_v3 | Deadlines from the facts gathered with get_supplier_questions | Customer | | get_state_lien_guide | One state's lien guide: rules, statute citations, deadline table and FAQs | None | | list_state_lien_guides | Every guide (50 states and DC) with its code, title and slug | None | | calculate_lien_deadline | Invoice-based deadlines (local server only) | Customer | | list_supported_states | Jurisdictions the invoice calculation accepts (local server only) | Customer |

Inputs, outputs and statuses are in the tool reference.

Privacy and safety

• Account usage. Supplier discovery and calculations require a customer key. Discovery uses no calculation allowance; completed calculations consume plan allowance. Hosted callers send their own Authorization: Bearer <key> on each request; local callers set LIENDEADLINE_API_KEY. The hosted server never uses a service-wide key. State guides remain public.
• What's sent. The facts you give (state, dates, project type, who hired you and your yes, no or unknown answers) go to the LienDeadline API to calculate. Guide lookups send only a state code.
• Hosted server. Its logs record the method, status and response time of each request, never your inputs. Google Cloud's own request log also records the URL, client IP address and user agent. The server may count usage anonymously in PostHog: tool name, success, duration and client family, with no inputs, results or IP addresses.
• Local server. It has no telemetry of its own.

Details: LienDeadline privacy policy.

Not legal advice

Results are educational baselines calculated from published state rules. Statutes change and every project is different, so verify critical deadlines with counsel before relying on them. LienDeadline is not a law firm and does not file anything on your behalf.

Links

• Website: liendeadline.com, with a setup guide for this server
• Agent skill and plugins: liendeadline.com/agent-skill and LienDeadline/skills
• Support: [email protected] or liendeadline.com/contact
• Terms of service: liendeadline.com/terms
• Privacy policy: liendeadline.com/privacy
• Help center: liendeadline.com/help
• Security: report issues privately as described in SECURITY.md
• Contributing and development: CONTRIBUTING.md
• License: MIT