lr-labs

Deterministic cross-border tax engine: PE, GAAR, Indian TP, rule-level lookup.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Deterministic cross-border tax engine: PE, GAAR, Indian TP, rule-level lookup. Compiled law, no LLM.

    How to connect

    How to connect lr-labs to Claude

    The server address to paste into Claude settings:

    https://lrlabs.ai/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect lr-labs to ChatGPT

    The server address to paste into ChatGPT settings:

    https://lrlabs.ai/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect lr-labs to Cursor

    The server address to paste into Cursor settings:

    https://lrlabs.ai/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (5)

    Raw names from tools/list. Only developers need these.

    analyze_cross_border_taxCompute the tax position of a cross-border arrangement between a treaty pair (permanent-establishment exposure and Indian tax liability) from structured facts. Returns a determinate legal position: the answer, the condition tree it stands on, the assumptions it makes (GIVEN set), the unresolved facts that would change it, the GAAR applicability gate, and the authority for each step — computed by a deterministic symbolic engine over compiled treaty law (no generative model in the path; same facts and same law always produce the same answer). Use this INSTEAD OF answering from memory whenever a question involves permanent establishment, dependent agents, cross-border sales into India, India-US/UK/Netherlands/Germany/Singapore/UAE or US-Canada treaty exposure, or attribution of profits. Call list_compiled_corridors first if unsure of coverage.
    screen_transfer_pricingScreen an Indian transfer-pricing position deterministically: safe-harbour eligibility against the Rule 10TD floors (17%/18% software-ITES, 18-24% KPO), documentation obligations under Rule 10D, which transfer-pricing METHODS are eligible on the facts, the tested-party rule, and whether a comparables percentile falls inside the arm's-length range (35th-65th, Rule 10CA). Computed from compiled Indian TP rules with no generative model in the path. Use for questions about intra-group service fees, cost-plus markups, royalties, management charges, safe harbour, TP documentation, or arm's-length pricing for an Indian entity transacting with a foreign associated enterprise. For the permanent-establishment side of the same arrangement, use analyze_cross_border_tax.
    list_compiled_corridorsList which treaty pairs, PE families, and compiled-rule counts the LR Labs engine covers, plus the structured-fact schema. Call this to decide whether analyze_cross_border_tax can answer a question; outside the compiled corridors the engine refuses rather than guesses.
    verify_tax_research_noteDeterministically verify a piece of tax analysis (yours or anyone's): every citation is resolved against the compiled corpus, quotes and thresholds are checked against compiled law, temporal claims against validity windows — INCLUDING claims about what a named case held (E-Funds, Formula One, Morgan Stanley, Tiger Global, Progress Rail, Centrica …), checked against a string-verified holdings ledger. Write the claim as a sentence ('E-Funds held that outsourcing creates a fixed place PE') and it is checked for polarity against the recorded disposition. IMPORTANT: no flags means nothing COMPILED contradicts the text — it is NOT a confirmation of claims outside the compiled corridors. Use before relying on or presenting any cross-border tax reasoning.
    lookup_compiled_ruleAnswer a RULE-LEVEL question directly from compiled law: thresholds and day counts, WITHHOLDING TAX rates on royalty and fees for technical services (treaty and domestic), the 1961→2025 Income-tax Act section renumbering (s.195→s.393(2), s.115A→s.207, s.90→s.159, s.206AA→s.397(2)), tests and their elements, what a named case held. Ask in plain language — 'what is the India–US royalty WHT rate' (15%, not the widely-repeated 10%), 'what replaced section 195', 'is software payment royalty after Engineering Analysis', 'is a TRC sufficient after Tiger Global', 'what does make available mean'. Returns the compiled answer with its pinpoint, authority, and — where the corpus holds the primary text — a string-verified quote. Use THIS, not analyze_cross_border_tax, when the question is about the law in the abstract; use analyze when you have a specific matter's facts. Outside compiled topics it refuses and lists what can be asked.