fmeca

The deterministic, offline kernel for structured FMECA (Failure Modes, Effects & Criticality Analysis).

The caller supplies observations — never scores. This kernel owns the structure and the arithmetic: a typed failure-mode / mitigation ledger over an append-only event log, a fixed evidence→score map, a locked S×P criticality matrix (swappable between a 3×3 qualitative default and the NASA GSFC-HDBK-8004 5×5), the prevent→detect→fail-fast mitigation discipline, computed residual risk, issue detection, and a readiness gate. Criticality, residual, and standing are computed by a fold over the log — never stored. No LLM, no network.

Stateless one-shot

use fmeca::{analyze, AnalyzeInput, Domain, EntityRef, MatrixStrategy};

let failure_modes = vec![AnalyzeInput {
    id: "fm-1".into(),
    component: EntityRef::new("checkout-service"),
    description: "Payment double-charge on retry".into(),
    cause: None,
    effect: None,
    domain: Domain::Runtime,
    scope: None,
    severity_observations: vec!["data_loss".into()],
    probability_observations: vec!["happens_in_normal_use".into()],
    mitigations: vec![],
}];

let report = analyze(MatrixStrategy::default(), &failure_modes).unwrap();
println!("risk ranking: {:?}", report.risk_ranking);

Long-lived sessions

For multi-turn analyses, use Engine over a StateStore (a FilesystemStore is provided). It persists an append-only event log and replays it to compute state, so restart survival is free:

use std::sync::Arc;
use fmeca::{Engine, FilesystemStore};

let store = Arc::new(FilesystemStore::new("./fmeca-state"));
let engine = Engine::new(store);
let state = engine.open_session("design-review").unwrap();
println!("ready: {}", state.readiness.ready);

See the root README for the MCP server and the full design rationale.

License

Apache-2.0.