IX-Decriel

Decriel is a research programming language for explicit effects and capabilities. This v0.2.0 release implements a small checked language and a mediated Rust execution interface. It does not ship an operating system sandbox, a real network/file/process adapter, authenticated human approvals, or a production audit store.

What works

• A lexer, parser, AST, source spans, and diagnostics for modules and declarations.
• Checked function bodies containing read, write, network, or execute operations against exact symbolic targets.
• Semantic rejection when an operation lacks a matching capability or effect, targets a policy deny symbol, or uses an unsupported security form.
• A mediated execution API that requires an external grant independently of source declarations and a human review provider when policy requires it. An approval interface is not an authentication service by itself.
• Source SHA-256 passed to grant, review, and host callbacks for revision binding. A configured evidence policy blocks effects when the host's pre-action record callback fails. Failure after an effect is reported without claiming rollback.
• A simulation CLI with a synthetic grant, no real effects, and no human approval. Denials exit nonzero.

Try it

Requires Rust 1.98.1. The repository pins the toolchain and Cargo.lock.

cargo check --workspace --all-targets --locked
cargo fmt --all -- --check
cargo clippy --workspace --all-targets --locked -- -D warnings
cargo test --workspace --all-targets --locked
cargo run --locked -- check examples/secure_service.dcr
cargo run --locked -- simulate examples/simulated_network.dcr request

For an intentional compile-time policy denial:

cargo run --locked -- check examples/invalid/denied_shell.dcr

For an intentional runtime review denial in the no-op simulation:

cargo run --locked -- simulate examples/secure_service.dcr review_gate

The latter two commands return exit status 2. ast <file> displays parsed syntax, inspect <file> reports source metrics, and --help lists commands.

Language and boundary

module example {
    capability network vendor;
    effect network vendor;
    effect evidence evidence_trace;
    policy requires human_review;
    policy ensures evidence_trace;

    fn request {
        network vendor;
    }
}

The vendor identifier is a symbolic binding. It is not a destination or a permission granted by the source author. The trusted host must bind it to a specific resource. To perform a real effect, an integrator calls check and CheckedModule::run with implementations of GrantAuthority, ReviewAuthority, and OperationHost. The grant and review providers must authenticate and scope their decisions to the digest, function, operation, target, and execution context. The host must isolate and audit real effects.

Legacy fn name; syntax is still recognized by ast but fails check. The same is true of unsupported security declarations such as capability secret and policy allow; the compiler does not silently treat them as enforcement.

Read the checked language subset and the threat model before building an adapter. The validation report records the local checks and their limits. Handoff instructions cover Windows validation and an existing GitHub clone.

Project status

The original archive's CI failure was formatting drift. This handoff pins rustfmt through the Rust toolchain file and passes local formatting, Clippy, build checking, and 61 tests. Remote GitHub CI has not run for this handoff until it is committed and pushed. Security claims are limited to the checked subset and its trusted-host interface. Independent security review remains necessary before using it to protect real resources.

Decriel stands for Declarative Effects and Capabilities for Runtime Integrity, Evidence, and Least-Authority. Copyright 2026 Bryce Lovell. Apache-2.0; see LICENSE and NOTICE.