# Mutation

- [Overview](/docs/mutation/overview/) — What mutation testing is and why it exists, explained without jargon
- [Introduction](/docs/mutation/testing/) — What mutation testing is and why it matters
- [Smallest Example](/docs/mutation/smallest-example/) — The simplest possible mutation-testing example: one function, one test, one mutant
- [Golden path](/docs/mutation/workflow/) — Step-by-step guide from weak tests to strong ones
- [Lie detection](/docs/mutation/lie-detector/) — Find tests that pass but never actually check anything
- [Designing for mutation](/docs/mutation/design-guide/) — How to write Vary code that mutation testing can measure well
- [Oracles](/docs/mutation/oracles/) — How tests decide whether program output is correct
- [Contracts](/docs/mutation/contracts/) — How contracts kill mutants automatically and how contract adequacy measures specification strength
- [Operators](/docs/mutation/operators/) — All 33 mutation operators: 27 AST operators (17 classic + 10 semantic) and 6 bytecode operators
- [Lie detection: deep dive](/docs/mutation/lie-detector-deep/) — Ledger demo showing how contracts and exact assertions interact with lie detection
- [Observability](/docs/mutation/observability/) — Runtime tracing, differential detection, and assertion groups for understanding why mutants survive
- [Advanced overview](/docs/mutation/advanced/) — Six pillars that turn mutation scores into actionable quality signals
- [Oracle analysis](/docs/mutation/oracle-analysis/) — Oracle graph structure, determinism classification, and oracle quality validation
- [Effects & integrity](/docs/mutation/effects/) — Effect classification, nondeterministic mutant filtering, runtime sealing, and integrity scoring
- [Signatures & manifest](/docs/mutation/signatures/) — Stable mutant identities, expression IDs, and the mutation manifest for CI and tooling
- [Infrastructure](/docs/mutation/infrastructure/) — Caching, quarantine, policy gates, certificates, result storage, and CLI reference
- [Equivalent mutants](/docs/mutation/equivalent-mutants/) — Detecting and handling mutants that cannot be killed because they are semantically identical to the original
- [Strict mode](/docs/mutation/strict-mode/) — Evidence-based test selection, kill-first scheduling, warm workers, and the hot-swap backend
- [Benchmark](/docs/mutation/benchmark/) — Cross-mode parity benchmark that validates strict-mode optimizations preserve correctness
- [Fast mode](/docs/mutation/fast-mode/) — Heuristic test-filter narrowing with a continuous validation pass that auto-falls back when miss rate is too high
- [Incremental inference](/docs/mutation/incremental-inference/) — Per-mutant reuse of prior outcomes when source, tests, compiler, and operators are unchanged
- [Parity gate](/docs/mutation/parity-gate/) — Cross-backend parity validation: every performance backend must match the fresh-loader reference
- [Survivor tail](/docs/mutation/survivor-tail/) — Per-file accounting that separates the main mutant loop from the flake-detection rerun pass