# blazingly-contract
Runtime-neutral, canonical API contracts for Blazingly.
The crate owns the semantic source of truth shared by HTTP, MCP, AI
documentation, internal RPC, and future mesh tooling:
- versioned canonical encoding independent of declaration order;
- model, input, output, typed-error, dependency, and security metadata;
- aliases, nested validation, and stable custom-validator identities;
- pull-based streaming request-body inputs without a runtime dependency;
- MCP discovery and agent risk, confirmation, and idempotency policies;
- SHA-256 contract fingerprints;
- semantic compatibility reports.
It intentionally does not depend on Tokio, an HTTP server, an MCP transport,
proc macros, or runtime dependency injection. The default `std` feature can be
disabled for `no_std + alloc` consumers.
```rust
use blazingly_contract::{Compatibility, OperationContract};
fn verify_upgrade(previous: &OperationContract, current: &OperationContract) {
let report = Compatibility::compare(previous, current);
assert!(report.is_backward_compatible());
println!("{}", current.fingerprint());
}
```
The Rust API follows Semantic Versioning. Canonical bytes and fingerprints are additionally
versioned by `CURRENT_CONTRACT_FORMAT_VERSION`; changing the crate version does
not silently change a contract fingerprint.
Version `0.4` uses canonical format `1.3`, which carries value-type constraints
on `TypeDescriptor`, including collection items and nested values, while
preserving deterministic ordering and compatibility classification. Every
operation fingerprint changes across the `1.2` to `1.3` move, so recorded
compatibility baselines have to be recaptured. The new public `constraints`
field breaks a struct literal that names every `TypeDescriptor` field: use
`TypeDescriptor::scalar`/`model`/`new`, or add `constraints: Vec::new()`.
## Install
```toml
[dependencies]
blazingly-contract = "0.4"
```
Licensed under the MIT License.