# "Quickstart: Claude Code"

Install the dsail package, run dsail init once, and let Claude Code compile and check a policy from the repository.

For a coding agent working in a repository. Turn a written policy into rules a program can check, keep the rules in the repo, and call the hosted service for every check.

## 1. Install

```bash
pip install dsail
dsail init
```

`dsail init` writes three things into the repository, all idempotent: a Claude
Code skill at `.claude/skills/dsail/SKILL.md` carrying the authoring sequence
and grammar, a `dsail` entry in `.mcp.json` that launches the stdio proxy
`dsail mcp`, and a marked stanza in `CLAUDE.md`. Commit them; every later
session, by anyone, finds DSAIL without being told.

The package name `dsail` is reserved on PyPI. Until the public release ships,
install from the distribution Jaxon gives you (`pip install ./dsail-*.whl`).

## 2. One command

Ask Claude Code, in the repository:

> Enforce our expense policy: receipts over 75 USD, nothing over 5,000 USD.

It restates the policy, asks you to confirm, writes `policies/expenses.dsail`,
compiles it through the `dsail_compile` tool (the proxy forwards to the hosted
REST door over HTTPS), and replays a few adversarial claim dictionaries against
its own draft before showing you anything. An evaluation credential is obtained
automatically on the first call; nothing to sign up for.

## 3. A result

```bash
dsail check policies/expenses.dsail --claims claims.json --summary
```

```text
receipt_over_75   FALSE   counterexample: amount = 120 USD, has_receipt = false
within_cap        TRUE
```

For review by a person, `dsail serve policies/expenses.dsail` prints a
localhost link to the same review widget the chat clients render; approval
there is recorded on the service against the exact hash.

## What the agent gets

- The same ten `dsail_*` tools the chat clients have, with the same
  descriptions — the proxy publishes the bundled definitions verbatim.
- Results per assertion in four words, `TRUE`, `FALSE`, `UNKNOWN`, `AMBIGUOUS`,
  and no overall verdict to invent. Unknown is an answer, not a guess.
- A structured error on every failure, each carrying the `docs` URL of the page
  that resolves it ([Errors](../reference/errors.md)).

If the first call fails saying outbound network access is blocked, the message
names the one-time organisation-level fix; relay it verbatim.

Next: [Quickstart: REST](rest.md) for the production integration, or the
[REST API reference](../reference/rest-api.md).