### wai-quantum: bring your own quantum

People bring their own quantum hardware, provider accounts, on-premises devices or simulators; WAI gives the engine, the free job service and the verifier, and never pays for or resells hardware time. A run on a person's provider is planned, its cost shown before it is submitted, checked, and sealed like any other job.

- **The open provider protocol** (`extensions/quantum-providers.md`, `wai.quantum.provider/1`): JSON messages over HTTP or to a local process on its standard input and output; `describe` (native gates, connectivity, qubits, durations, a calibration snapshot id with optional per-qubit and per-pair errors, the billing unit and price or free), `estimate`, `submit`, `status`, `result` (counts keyed by classical bits, the highest first) and `cancel`; a program in the device's own gates, every angle an exact fraction of a turn, with its OpenQASM 3 beside it; error codes; what the receipt proves and what it does not.
- **wai-quantum-qpu:**
  - `open_provider`: the client over either transport (a credential only over https or to this machine; in a process's environment, never its command line), and `OpenProvider`, a `Provider` over it;
  - `reference`: the reference provider, the protocol around the exact simulator, served both ways (`wai-qpu reference`); free or priced per shot or job in exact decimals, with status polls, a readout error and a credential checked by its hash; the template to copy;
  - `conformance`: the checker and its vectors (`conformance/provider-v1.json`), the reference's counts pinned; jobs run only when every one is free or the person allows the spend;
  - `registry`: the person's list (`~/.config/wai/quantum-providers.json`), holding no credential; credentials in the keychain (the system `security` tool, or `secret-tool`), else a 0600 file, labelled so in every listing; environment variables still work;
  - `job`: the dry run (the exact native compile, the check by simulation, the provider's estimate and billing unit), the refusal of a run that is not free (or of unknown cost) until it is confirmed, and the seal of its counts;
  - `Provider` gains `details`, `estimate`, `submit_seeded` and `cancel`, each with a default.
- **The engine** (`engine::provider`): what a provider job may ask (counts of a program measured at the end, every angle dyadic), the measured result labelled `measured` with the circuit's exact distribution beside it (total variation distance, Hellinger fidelity, and what the shots alone leave), and its seal, which `job::verify` checks. `catalog::read` refuses a job that names a provider, so the job service never runs one on its own methods.
- **The command line:** `providers add|list|remove|describe|test|free|reference`, and `run --provider NAME [--dry-run] [--yes]` (a run that is not free exits 3 without `--yes`). The stdio MCP server gains `providers_list`, `provider_estimate` and `run_on_provider`; the last says it can spend the person's money and refuses without `confirm_cost: true` when the run is not free.
- **The desktop app:** `providers_list`, `provider_estimate` and `run_on_provider` commands; the Studio's **Your hardware** switch lists the providers, asks for the estimate and shows a dialog before a run that is not free. In a browser tab the switch says such runs go through the desktop app or the command line, since a tab must not hold a credential.
- **The job service** never routes to a provider and never takes a credential (its README says so; a job naming one is refused).
- **Docs:** `wai-quantum-qpu/bring-your-own-quantum.md` (adding a provider, the protocol, the reference as a template, what the receipt proves and what it does not, and what a person does to connect a real device).
- **CI:** `wai-quantum-qpu.yml` pins its three test binaries and the new tests by name, with a macOS leg for the keychain in a keychain file the test makes; `wai-quantum-cli.yml` follows the crate and pins the five end-to-end tests; `wai-quantum-studio.yml` runs the hardware switch's logic test. Nothing in them spends money.

