fuzz_targets/ — one binary per target; thin fuzz_target! wrappers (land with the wave-7 target tasks).
shared/ — the invariant logic, as a plain library so normal cargo test (stable toolchain) can replay the committed corpora through the same invariants (fuzz/shared/src/*.rs #[cfg(test)] modules; quinn's CI pattern). The fuzz binaries are nightly-only; the shared crate is stable-clean. It consumes alkstore's public API only and must never become a dependency of any workspace crate.
corpus/<target>/ — committed hand-made seeds (regenerate with python3 fuzz/gen_fuzz_seeds.py from the repo root). Grown corpora and artifacts are gitignored; each target task adds its !-negation line when its corpus lands.
run-detached.sh — mandatory runner for agent sessions: wraps cargo fuzz run in setsid + nohup + log redirection so an OOM in a target can never take down the agent host (research doc §5).
json.dict — JSON token dictionary for the structured targets.
gen_fuzz_seeds.py — deterministic seed generator (quiche pattern).

Targets

Target	Drives	Invariants
`payload_codec`	`encode_payload` / `payload_as::<T>` (`alkstore/src/payload.rs`)	no-panic on any byte sequence; every decode failure typed `Error::Codec`; deep nesting loud at serde_json's recursion limit; `Value` round-trip (serde_json canonicalization pinned); typed round-trip for a representative payload set
`every_parse`	the three `parse_every_interval` implementations (differential, through the engines' `#[doc(hidden)]` re-exports) + each engine's `skip_forward` boundary arithmetic	no-panic on any UTF-8-lossy string (each parser, each boundary path); typed rejection (`Error::InvalidSpec` on pg/mem, the substrate's error under its mapping on SQLite); three-way agreement on the Ok/Err partition and the `Ok` interval value (error identity not pinned — the SQLite `Result<i64, String>` vs `InvalidSpec` asymmetry is known); overflow posture: `skip_forward` over adversarial `(next_fire_at, now, interval)` triples rejects-or-saturates, never wraps or panics; the `n <= 0` and giant-`n` arms (leading zeros, digit overflow at exactly `i64::MAX/86400`, positive-zero rejection)
`name_validation`	`validate_name` / `validate_shared_name` / `validate_local_name` (`alkstore/src/validation.rs`)	no-panic on any byte sequence (lossy-decoded and `arbitrary`-structured strings); deterministic accept/reject (double-invocation-pinned); rejection only via the typed taxonomy — `Error::InvalidName` for empty/whitespace-only on both kinds, `Error::ReservedName` for the leading byte-exact `__alkstore_` prefix on the shared kind only (the local kind takes the non-empty rule only, so a leading reserved prefix is legal there); the reserved-prefix rule exact in every casing/boundary form (casing deviations, missing trailing underscore, embedded and whitespace-led forms accept); the rejection carries the supplied name verbatim (names are not trimmed); verdict-class length-independence across the probed neighborhoods (0↔1, 11↔12, 63↔64, 4095↔4096, 65536) — no length cap is pinned (ADR-008 §4), so no length is ever a rejection cause

Commands

cargo fuzz build and cargo fuzz run must be executed with fuzz/ (or deeper) as the working directory so rustup selects the pinned nightly toolchain — the detached runner handles that itself.

# build (nightly, pinned by rust-toolchain.toml inside fuzz/; run from fuzz/)
cargo fuzz build

# agent sessions: detached campaign (never foreground; CWD-independent)
FUZZ_RUNTIME_SECS=600 fuzz/run-detached.sh <target> [extra libfuzzer args...]

# corpus replay through the invariants (stable toolchain, no nightly)
cargo test --manifest-path fuzz/shared/Cargo.toml

# coverage
cargo fuzz coverage <target>

The fuzz workspace is excluded from the main workspace (exclude in the root Cargo.toml); it pins its own nightly toolchain via rust-toolchain.toml and does not affect the root workspace's stable toolchain or MSRV.