LienDeadline

liendeadline-mcp

MCP server for US mechanics lien and preliminary notice deadlines, built on the LienDeadline API.

Give it a supplier's delivery dates and project facts, and it returns the preliminary notice and lien filing deadlines with their statute sources and warnings.

Coverage

• Lien guides: all 50 states and DC. No key needed.
• Calculated supplier deadlines: Florida and Kansas private projects, the states whose supplier rules have been reviewed so far. No key needed. For other states, public projects, or when a relevant Florida payment/termination or Kansas extension answer is missing or unknown, the affected deadline is review_required (needs legal review) instead of a guessed date.
• Customer invoice calculation: 51 jurisdictions, with a LienDeadline customer API key.

Tools

Tool	Key	What it does
calculate_supplier_deadlines	none	Supplier notice and lien filing baselines from explicit delivery-event answers (supplier-events-v2)
get_state_lien_guide	none	Editorial guide for one state or DC: rule summary, statute citations, deadline table, FAQs
list_state_lien_guides	none	Every available guide, by code and title
calculate_lien_deadline	customer	Customer API: deadlines for one invoice from its invoice date and state
list_supported_states	customer	Customer API: jurisdictions the invoice calculation accepts

Every tool is read-only: none of them sends notices, files liens or makes payments.

Install

Requires Node.js 22 or newer. The server runs locally over stdio. The package ships npm-shrinkwrap.json, so npx installs the exact dependency versions each release was tested with. It is listed in the official MCP Registry as io.github.LienDeadline/liendeadline-mcp.

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

Claude Code:

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

Claude Desktop, Cursor, Windsurf and other clients that use an mcpServers JSON config:

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

VS Code (.vscode/mcp.json):

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

OpenAI Codex CLI:

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

For agent instructions that pair with these tools, see the LienDeadline agent skill, which is also packaged as a Claude Code plugin that installs this server.

Example

calculate_supplier_deadlines with a Florida commercial project where a subcontractor ordered the materials, deliveries ran from 2026-08-03 to 2026-09-10, and the owner confirms neither final payment nor termination occurred:

{
  "state": "FL",
  "first_delivery_date": "2026-08-03",
  "last_delivery_date": "2026-09-10",
  "project_type": "commercial",
  "hired_by": "subcontractor",
  "deliveries_complete": true,
  "florida_final_payment_status": "no",
  "florida_termination_status": "no"
}

returns, abbreviated:

{
  "contract_version": "supplier-events-v2",
  "status": "calculated",
  "state_code": "FL",
  "preliminary_notice": { "name": "Notice to Owner", "deadline": "2026-09-17", "status": "calculated" },
  "lien_filing": { "name": "Claim of lien", "deadline": "2026-12-09", "status": "calculated" },
  "statute_citations": ["Fla. Stat. § 713.06(2)(a)", "Fla. Stat. § 713.08(5)"],
  "disclaimer": "This is an educational baseline, not legal advice ..."
}

The same facts with both Florida answers omitted return "status": "review_required" and no dates. An unknown final-payment answer holds the notice date; an unknown termination answer holds the lien date. For Kansas, kansas_extension_status: "no" permits the ordinary lien baseline, while "yes", "unknown", or omission requires review and yields no lien date. Supply a Florida event date only with the matching "yes" answer. A blanket special_events_reviewed flag is not accepted. Texas and public projects also need review. Ongoing deliveries return awaiting_final_delivery for the lien date when other facts permit it. The server checks that the result echoes exactly what was submitted and that unresolved events have no affected date; a mismatch is reported as an error, not as dates.

Customer API key (optional)

Only calculate_lien_deadline and list_supported_states need a key. Request API access through support@liendeadline.com or liendeadline.com/contact; keys are issued through the approved issuance process, not self-service. calculate_lien_deadline needs deadline:calculate; list_supported_states needs states:read. Set LIENDEADLINE_API_KEY in the MCP process environment using your local secret launcher. A browser session, QuickBooks/Procore token or legacy API key is not a customer credential. Rotation or revocation requires replacing the key and restarting the MCP process.

In a JSON config, the key goes in the server's env block:

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

The placeholder above is not a credential. Protect a configuration containing a real key as a secret; do not commit, share or include it in support logs. Keys must never appear in URLs, tool arguments or browser storage. Missing or malformed keys fail locally before an HTTP request; the public tools work without a key.

Notes

• Responses are trimmed. A state guide is ~16 KB of which roughly 7 KB is rendered HTML; it is collapsed to the structured fields, which takes it to ~4,300 characters. The customer calculate endpoint returns the same object three times and is collapsed to one.
• Guides are not calculations. Guide day counts are editorial summaries. Filing dates come only from calculate_supplier_deadlines; anything it does not calculate needs qualified review.
• API origin: customer tools send Authorization: Bearer <key> only to https://secure-api-v1.liendeadline.com, using POST /api/v1/calculate-deadline and GET /api/v1/supported-states. There is no anonymous demo fallback. LIENDEADLINE_API_URL accepts a bare HTTP(S) origin for the public tools; customer tools reject every other origin, including staging, alternate ports and insecure HTTP. URL credentials, paths, queries and fragments are rejected. All requests reject redirects. Public tools never send credentials.
• Denials: 401 means check expiry/rotation/revocation, 403 means check endpoint scope and current account access, 429 means retry later, and 503 means the customer API is unavailable. Tools return an MCP error with a safe message; denial bodies and network exception details are not echoed.

Privacy and data

The server has no telemetry and stores nothing. Each tool call makes at most one HTTPS request to https://secure-api-v1.liendeadline.com:

• calculate_supplier_deadlines sends the submitted project facts (state, delivery dates, project type, who hired the supplier and the review answers). The endpoint is stateless and does not save them.
• The guide tools send only the state code.
• The customer tools send the invoice facts and the customer key as a Bearer header.

LienDeadline's privacy policy covers the API.

Development

With Node 22.23 or newer, run npm ci --ignore-scripts, npm run typecheck, and npm test. Tests use synthetic credentials and mocked HTTP without API/provider access. Hosted CI also compiles the package. Pull requests and scheduled checks do not call the live API or require secrets.

npm run smoke is an explicit live stdio check against the production API. It requires LIENDEADLINE_RUN_LIVE_SMOKE=1, runs the public tools, and runs the customer tools only when LIENDEADLINE_API_KEY is also set. Do not use a real customer key for routine CI or unapproved live acceptance. Releases follow RELEASING.md.

Not legal advice

Results are calculated baselines from published state rules. Statutes change and facts vary between projects. Verify critical deadlines with counsel before relying on them. This is not a law firm and does not file anything on your behalf.

Licence

MIT