DSAIL MCP server

dsail

<!-- mcp-name: ai.jaxon/dsail -->

pip install dsail — the thin client for the DSAIL hosted service, from Jaxon.

Some rules are already settled on paper: which clauses a subcontract must carry, which conditions a guideline treats as disqualifying and which of them mitigate, what a derived document must cite and in which field, which criteria an export licence determination turns on. Nobody needs a model's opinion on those. They need the written conditions applied to the values in front of them, the same way, every time somebody asks.

DSAIL is for exactly that. Turn a written policy into rules a program can check, and get the same answer every time. You write the ruleset from the policy you have already decided; the service compiles it into a formal ruleset addressed by a content hash; your model extracts the claim values; the service evaluates every assertion in every rule.

Results come back per assertion — TRUE, FALSE, UNKNOWN or AMBIGUOUS. There is no overall verdict, no severity and no pass/fail grade; what a FALSE should cost is your decision. A FALSE carries the solver's counterexample, so you can show the rule that decided, with a counterexample. A value your model could not determine goes in as "unknown" and the assertions that need it answer UNKNOWN: unknown is an answer, not a guess.

No model in the loop on our side. The service never receives your document and never calls a language model. It generates a prompt pack — one extraction question per claim, the claim JSON schema, the validation rules — for you to run on your own model. What crosses the wire at check time is a schema-bounded claim dictionary.

Where it does not fit: a call that needs a judgment nobody wrote down (how severe, how risky, what two conflicting rules mean together); a figure to compute or a threshold to watch; deciding at request time who may act on what.

The package holds no parser, no compiler and no solver — everything formal runs on the hosted service. It gives you dsail.Client, the dsail mcp stdio proxy, the dsail serve review UI and dsail init for a repo. Docs, every page also served as markdown: https://docs.agents.jaxon.ai

Install

pip install dsail
dsail version

Python 3.10 or newer. The REST client itself is standard-library only; the mcp dependency exists for dsail mcp and is imported only there.

Sixty seconds, end to end

dsail init                                    # once per repository; commit what it writes
cat > policies/expenses.dsail <<'EOF'
version 1.3;
// @ask amount What is the total amount of this expense claim, in USD?
// @unit amount USD
declare amount as numeric;
// @ask has_receipt Is an itemised receipt attached?
declare has_receipt as boolean;
assert receipt_over_75 { Implies(amount > 75 "USD", has_receipt) };
assert within_cap { amount <= 5000 "USD" };
EOF
dsail compile policies/expenses.dsail --review   # what a person would be signing
dsail prompt-pack policies/expenses.dsail --render
echo '{"amount": "120 USD", "has_receipt": false}' > claims.json
dsail check policies/expenses.dsail --claims claims.json --summary
dsail serve policies/expenses.dsail              # hand the reviewer the printed link

The client, in a production service

import dsail

client = dsail.Client()                                  # DSAIL_URL, DSAIL_CREDENTIAL honoured
compiled = client.compile(open("policies/expenses.dsail").read())
pack = client.prompt_pack(ruleset_hash=compiled.ruleset_hash)

claims = pack.empty_claims()                             # every claim "unknown" to start
for prompt in pack.prompts:                              # run each on YOUR model
    claims[prompt.claim] = my_model.extract(document, prompt.render())

Shortened. The full README is on GitHub.