Rust Review

Rust Security Review

Runs in the main conversation (invoke via /rust-review:rust-review). Orchestrator owns the Task* ledger as bookkeeping for retries; workers and judges have no Task tools. Workers and judges are named plugin subagents (rust-review:rust-review-worker, rust-review:rust-review-dedup-judge, rust-review:rust-review-fp-judge); tool sets are declared in plugins/rust-review/agents/*.md. Findings are exchanged via markdown-with-YAML files in a shared output directory.

When to Use

Rust application/library security review: safe/unsafe boundary auditing, memory safety in unsafe blocks, concurrency hazards, panic-induced DoS on servers, FFI safety, async-runtime mistakes.

When NOT to Use

• Pure-C / pure-C++ codebases — use c-review instead.
• Smart contracts (Solana programs / NEAR contracts / Ink!) — use solana-vulnerability-scanner or the contract-specific skill.
• Kernel-mode Rust drivers without userspace allocator — coverage is incomplete; flag as advisory only.
• Secrets/key memory hygiene (zeroization, Zeroize/ZeroizeOnDrop/secrecy usage, lingering stack/heap copies) — use the zeroize-audit skill; rust-review does not cover memory zeroization.

Subagents

Tools come from each agent's frontmatter at spawn time. The orchestrator's Task*/Agent/Bash/etc. come from this skill's allowed-tools. Search-tool / Bash interaction: in current Claude Code, an agent granted Bash is not also granted the dedicated Glob or Grep tools (the calls return No such tool available; the harness expects find/grep/rg via Bash instead). So only the dedup-judge — the one agent that holds no Bash — uses Glob; the worker, fp-judge, and the orchestrator resolve and search paths with Read / Bash find / rg / grep / test -f instead. Because the cluster/finder prompt seeds are written in ripgrep regex syntax (\s, \d, \b), Bash-holding agents must run them with rg. If rg is not installed its call fails loudly (command not found) — fall back to grep -E with POSIX classes (\s→[[:space:]], \d→[[:digit:]], drop \b), never a raw-\s grep whose silent empty becomes a bad cleared. Do not reintroduce Glob/Grep into a Bash-holding agent's protocol.

Architecture

coordinator: write context.md → build_run_plan.py → TaskCreate × M
          → spawn primer (foreground) → spawn M workers (parallel)
          → classify Phase-7 outcomes + write findings-index.txt
          → dedup-judge → fp-judge → report safety net (SARIF + REPORT.md) → return REPORT.md

Output directory contains: context.md, plan.json, worker-prompts/, findings/, findings-index.d/ (per-worker shards), findings-index.txt, coverage/ (per-worker coverage-gate files), run-summary.md, dedup-summary.md, fp-summary.md, REPORT.md, REPORT.sarif.

Path convention: every later phase shells out to ${RUST_REVIEW_PLUGIN_ROOT}/scripts/*.py, so resolve that variable first to the plugin directory that contains prompts/clusters/unsafe-boundary.md (and scripts/build_run_plan.py). Try in order, first hit wins:

1. Native Claude Code — ${CLAUDE_PLUGIN_ROOT}, accepted if Bash: ls "${CLAUDE_PLUGIN_ROOT}/prompts/clusters/unsafe-boundary.md" resolves.
2. Codex — ${CODEX_PLUGIN_ROOT} (set it the same way if that var is present and resolves the marker).
3. Fallback search — covers Codex installs under ~/.codex, Claude installs under ~/.claude, and a local checkout / repo run: Bash: find ~/.claude ~/.codex . -path '*/plugins/rust-review/prompts/clusters/unsafe-boundary.md' -print -quit 2>/dev/null. Take the match and strip the trailing /prompts/clusters/unsafe-boundary.md to get the root (the home dirs are searched before . so an installed copy wins over any vendored copy in the audited repo).

Set RUST_REVIEW_PLUGIN_ROOT to the resolved root. If all three fail, abort with a message naming the roots searched — do not enter Phase 4 with an empty variable (every python3 "${RUST_REVIEW_PLUGIN_ROOT}/scripts/..." call would fail with a confusing path error).

Scope convention: keep two scopes separate throughout the run:

• finding_scope_root — the user-requested audit subtree. Workers may only file findings whose vulnerable location is inside this subtree.
• context_roots — read-only repo roots/files workers and judges may inspect to verify reachability, callers, wrappers, build flags, mitigations, and threat-model details. Default to . unless the user explicitly forbids broader context. Reading context outside finding_scope_root is allowed; filing findings there is not.

Rationalizations to Reject

• "unsafe is rare, so hand-skip the memory-safety cluster." Don't edit the cluster list — set has_unsafe accurately in Phase 1 and let build_run_plan.py decide. Every memory-safety bug class (UAF, double-free, uninitialized reads, Vec::set_len, union UB) requires unsafe, so the planner runs the whole memory-safety cluster when has_unsafe=true and correctly omits it when false — there is no "run it anyway." The unsafe-boundary cluster is different: it has no requires and always runs (consolidated; its safety-doc and repr(C) hygiene apply to FFI declarations even without visible unsafe { } blocks).
• "The compiler caught it." The borrow checker proves absence of safe-code data races; it proves nothing about unsafe blocks, panic reachability, ABBA deadlocks, atomic-load/store sequencing, or FFI ABI mismatch.
• "unwrap() is fine if it's // SAFETY: documented infallible." // SAFETY: documents unsafe operations, not infallibility claims. An unwrap() on documented-infallible input is still risky if the documentation is wrong — file as low severity and let the FP judge decide.
• "has_unsafe=false so skip the run." Pure safe-Rust crates still have panic-DoS, atomic races, drop-panics, and trait-implementation hazards. Run the always-on clusters.
• "Background spawns parallelize the workers." They do not — Agent calls in a single assistant message already run concurrently. run_in_background=true defeats the Phase 6a primer cache, so every worker pays full cache-creation (cache_read_input_tokens=0) and the ~15 K-token primer is wasted M times. Default: omit run_in_background from worker spawns.
• "I'll re-derive the cluster list / paths / pass prefixes inline instead of running build_run_plan.py." The script is the only authority for selection and rendering. Paraphrasing it drops fields that the worker self-check requires, producing worker-N abort: spawn prompt malformed. Always run the script and Read plan.json.
• "The run partially succeeded — I'll just write REPORT.md from what completed." Hiding partial runs behind a successful report is a correctness bug. If any Phase-5 cluster task is not completed, surface it prominently in run-summary.md and the final response.
• "Zero findings — skip Phase 8." Always run both judges and Phase 8b: dedup-judge writes a minimal no-op dedup-summary.md on an empty index, fp-judge writes empty REPORT.md/REPORT.sarif, and Phase 8b's SARIF generator emits results: [] for the empty case. SARIF consumers depend on a stable artifact set.
• "Bash: ls README* is fine for the preflight." Under zsh, an unmatched glob aborts the whole compound command before 2>/dev/null runs. Use find (never fails on no-match) — and not Glob, which is unavailable to an agent that also holds Bash.

Orchestration Workflow

Run these phases in the main conversation.

Phase 0: Parameter Collection

Entry: skill invoked. Exit: threat_model, worker_model, severity_filter resolved; scope_subpath resolved or set to "."; finding_scope_root=scope_subpath; context_roots resolved.

The skill is invoked directly (no command wrapper). Parse any free-text arguments the user passed on the /rust-review:rust-review line (e.g. flamenco only, high severity only, use haiku) and pre-fill the answers they imply — then ask for any missing required parameters with one AskUserQuestion call. Never silently default the required parameters.

Required parameters:

Call AskUserQuestion exactly once with only unresolved required parameters (threat_model, worker_model, severity_filter) plus scope_subpath only when the user explicitly requested a narrowed scope but it is ambiguous. If the required parameters were all pre-filled and scope is absent or resolved, skip the question.

After resolving scope_subpath, set finding_scope_root="${scope_subpath:-.}". Set context_roots="." by default so workers can verify callers/build settings outside a narrowed subtree without filing out-of-scope findings. If the user explicitly asks to forbid broader context, set context_roots="${finding_scope_root}" and note that reachability confidence may be lower.

Phase 1: Prerequisites

Entry: Phase 0 complete. Exit: has_unsafe, has_ffi, has_concurrency, has_async, has_packed_repr, has_fs_io flags determined. Abort with a clear message if no *.rs files exist under ${finding_scope_root}.

Probe within ${finding_scope_root:-.} with the Bash commands below (non-empty output ⇒ flag true). The dedicated Grep/Glob tools are unavailable to this orchestrator because it holds Bash — use grep/rg/find via Bash. (The probe regexes use \s/\b; if your grep lacks GNU \s support, run them with rg -uu — which honors \s and still searches ignored files — or, if rg is not installed either, replace \s→[[:space:]] and drop \b. Widening is safe here: a false-positive capability flag only adds a harmless extra worker, whereas a missed match would skip a whole pass.)

# Rust source presence (precondition)
find "${finding_scope_root:-.}" -name '*.rs' -print -quit

# has_unsafe
grep -rlE '\bunsafe\s+(extern|fn|impl|trait)\b|\bunsafe\s*\{' --include='*.rs' "${finding_scope_root:-.}" | head -1

# has_ffi
grep -rlE 'extern\s+"(C|system|stdcall|cdecl|win64|sysv64|aapcs|fastcall|thiscall|vectorcall|efiapi)(-unwind)?"|\bextern\s+fn\b|extern\s+\{|#\[repr\((C|transparent)\b|\b(CString|CStr)\b|use\s+(libc|core::ffi|std::ffi|std::os::raw|cty)|\blibc::|\b(bindgen|cbindgen)\b|\bc_void\b' --include='*.rs' "${finding_scope_root:-.}" | head -1

# has_concurrency
grep -rlE '\b(std::(thread|sync)|parking_lot::|crossbeam|rayon::|tokio::sync|core::sync::atomic|std::sync::atomic|Atomic[A-Za-z0-9_]*|UnsafeCell|static\s+mut|unsafe\s+impl\s+(Send|Sync)|memmap2::|Mmap(Options|Mut)?|MAP_SHARED|shm_open|mmap\s*\(|memfd_create|shared_memory|raw_sync|CreateFileMapping|MapViewOfFile|once_cell|sigaction|signal_hook|nix::sys::signal|libc::signal|libc::sigaction)' --include='*.rs' "${finding_scope_root:-.}" | head -1

# has_async
grep -rlE '\basync\s+(fn|move|\{)|\.await\b|tokio::|async_std::|futures::' --include='*.rs' "${finding_scope_root:-.}" | head -1

# has_packed_repr (outer #[repr(...packed...)] and inner #![repr(...packed...)])
grep -rlE '#!?\[repr\([^]]*packed' --include='*.rs' "${finding_scope_root:-.}" | head -1

# has_fs_io (path types / construction)
grep -rlE '\bPathBuf\b|\bPath\b' --include='*.rs' "${finding_scope_root:-.}" | head -1

# has_fs_io (fs module and file APIs)
grep -rlE '\bfs::|\bFile::(open|create)\b|OpenOptions|\.exists\(\)|\.metadata\(|symlink_metadata|read_dir|read_to_string' --include='*.rs' "${finding_scope_root:-.}" | head -1

As with the other flags, non-empty output (from either probe) means the flag is true. These detectors are intentionally conservative: when in doubt they set the flag true, because a false-positive flag only costs a harmless extra worker while a false-negative would skip a real pass. has_fs_io keys on path types (PathBuf/Path, which also covers &Path parameters and bare Path:: calls) and filesystem anchors (fs::/File::/OpenOptions/read_dir/…) rather than the bare .join(/.push( calls — path construction is reached via the path-type anchors, so leaving join/push out of the gate avoids matching unrelated iterator/JoinHandle joins and Vec::push that would make the gate fire on nearly every crate.

Note for Cargo.toml: also probe for [dependencies] tokio, async-std, etc., to set has_async=true even if the scope subpath has no .await yet (library crates often re-export).

Also probe Cargo.toml presence (informational — note in run-summary.md whether the audit was over a Cargo workspace, single crate, or loose .rs files):

# context_roots may be comma-separated (build_run_plan.py treats it as a list),
# so probe each root rather than passing "a,b" as one (nonexistent) path.
echo "${context_roots:-.}" | tr ',' '\n' | while IFS= read -r root; do
  find "${root:-.}" -name 'Cargo.toml' -print -quit
done | head -1

Phase 2: Output Directory

Entry: Phase 1 flags set. Exit: absolute output_dir resolved; ${output_dir}/findings/ and ${output_dir}/coverage/ exist.

Resolve an absolute path for output_dir (default: $(pwd)/.rust-review-results/$(date -u +%Y%m%dT%H%M%SZ)/):

mkdir -p "${output_dir}/findings" "${output_dir}/coverage"

The coverage/ subdirectory holds per-worker coverage-gate audit files (coverage/worker-{N}.md). Workers write to it instead of embedding the table in their reply — see agents/rust-review-worker.md step 5.

Phase 3: Codebase Context

Entry: ${output_dir} exists. Exit: ${output_dir}/context.md written.

Skim README.{md,rst,txt} and any build/manifest file (Cargo.toml, Cargo.lock, rust-toolchain.toml, build.rs) — preflight with find (via Bash) before any Read (a Read on a missing file aborts the turn; Glob is unavailable to this orchestrator because it holds Bash). Do not use Bash: ls README* for the preflight: under zsh, an unmatched glob aborts the whole compound command before 2>/dev/null runs. Use find . -maxdepth 2 -name 'README*' -o -name 'Cargo.toml' -o -name 'rust-toolchain.toml' -o -name 'build.rs', which never fails on no-match.

Write ${output_dir}/context.md with: YAML frontmatter (threat_model, severity_filter, scope_subpath, finding_scope_root, context_roots, has_unsafe, has_ffi, has_concurrency, has_async, has_packed_repr, has_fs_io, output_dir, cargo_manifest as workspace/single-crate/absent plus path when present), then a short markdown body with five sections — Purpose (1-3 sentences), Scope (what's in finding_scope_root, and that findings outside it are out of scope), Entry points (where untrusted data enters: network, files, CLI, IPC, serde deserialization, FFI inputs), Trust boundaries (sandboxed vs trusted peers vs arbitrary remote), Existing hardening (fuzzing harnesses, MIRI runs, clippy::pedantic, cargo-deny, cargo-audit).

Phase 4: Build Run Plan (deterministic)

Entry: capability flags + threat_model known; ${output_dir}/findings/ exists. Exit: ${output_dir}/plan.json and ${output_dir}/worker-prompts/*.txt written; M = worker_count known.

Selection, filtering, path resolution, and spawn-prompt rendering are delegated to the script to keep spawn prompts complete and consistent:

python3 "${RUST_REVIEW_PLUGIN_ROOT}/scripts/build_run_plan.py" \
  --plugin-root "${RUST_REVIEW_PLUGIN_ROOT}" --output-dir "${output_dir}" \
  --threat-model "${threat_model}" --severity-filter "${severity_filter}" \
  --scope-subpath "${finding_scope_root:-.}" --context-roots "${context_roots:-.}" \
  --has-unsafe "${has_unsafe}" --has-ffi "${has_ffi}" \
  --has-concurrency "${has_concurrency}" --has-async "${has_async}" \
  --has-packed-repr "${has_packed_repr}" --has-fs-io "${has_fs_io}" \
  --max-passes-per-worker 4

The script writes plan.json + worker-prompts/worker-N.txt + (if --cache-primer=true, the default) worker-prompts/cache-primer.txt, and prints a JSON summary on stdout. Exits non-zero on any missing prompt — surface the message and stop. With the default --max-passes-per-worker 4 the planner selects ~8 clusters → M ≈ 13 workers for pure safe Rust (no FFI / concurrency / async; info-disclosure is always on), ~10 clusters → M ≈ 15 for concurrent safe Rust, and ~15 clusters → M ≈ 23 for full Rust (unsafe + FFI + concurrency + async, plus input-os-safety when has_fs_io and layout-safety when has_packed_repr). M is the post-chunk worker count (plan.workers.length), so it runs above the cluster count — chunking splits multi-pass non-consolidated clusters (e.g. panic-dos, memory-safety), while the two consolidated clusters (unsafe-boundary, concurrency-locking) are never chunked: one worker each builds the shared inventory once and runs all its phases. recursion-dos is one pass per worker. After it returns, Read plan.json for the structured selection — never re-derive filtering or paths.

--max-passes-per-worker N caps the per-worker pass count. The planner deterministically splits any non-consolidated cluster with more than N passes into ceil(K/N) contiguous chunks; each chunk becomes its own rust-review-worker spawn with a -{i}-suffixed cluster_id (e.g. panic-dos-1, panic-dos-2). Consolidated clusters (unsafe-boundary, concurrency-locking) are exempt — never chunked, regardless of pass count or override — so one worker builds their shared Phase-A inventory once and runs every phase (chunking a consolidated cluster would force each chunk to rebuild that inventory, which workers skip in practice). The shared prompt-cache prefix and Cluster prompt: path are byte-identical across chunks, so the cache primer still warms every worker. Default 4 is calibrated against the heavy-tail clusters in manifest.json. Some output-heavy non-consolidated clusters declare a smaller manifest-level max_passes_per_worker override so each expensive pass gets its own worker (e.g. recursion-dos). Pass --max-passes-per-worker 0 to disable all chunking, including manifest overrides (one worker per cluster).

Phase 5: Create Bookkeeping Tasks (orchestrator-internal)

Entry: ${output_dir}/plan.json exists; M = plan.workers.length. Exit: cluster_task_ids[] created (1:1 with plan.workers), all pending.

The task ledger is orchestrator bookkeeping only (TUI visibility + Phase-7 retry tracking) — workers never read or write it. One TaskCreate per worker, populating metadata with kind="cluster", worker_n, cluster_id, spawn_prompt_path, pass_prefixes, attempt=1 — all values copied verbatim from plan.workers[i]. Track cluster_task_ids[] in plan.workers order.

Phase 6: Spawn workers (optional cache-primer first, then M in parallel)

Entry: cluster_task_ids[] populated; per-worker spawn prompt files exist at ${output_dir}/worker-prompts/worker-N.txt. Exit: all M Agent calls — across every wave — have returned (the parallel spawn block(s) completed).

Phase 6a: Cache primer (gated on plan.run.cache_primer)

A parallel batch from cold start cannot share cache (all M requests dispatch simultaneously, none has finished writing). To warm the prefix, spawn a tiny primer first — foreground (background spawns don't share cache with subsequent foreground spawns).

If plan.run.cache_primer == true, build_run_plan.py has written ${output_dir}/worker-prompts/cache-primer.txt. Spawn it in its own assistant message: Read the file, pass verbatim as Agent prompt with subagent_type=rust-review:rust-review-worker, model=${worker_model}, description="Rust review cache primer", no run_in_background. The script wrote the prefix byte-identical to worker-1.txt through the <context> block — that byte-identity is what gives the parallel workers their cache hit. The primer trailer contains Cache primer: true, which the worker system prompt treats as a first-class mode and returns exactly worker-PRIMER abort: cache primer (no analysis performed) in one text response with zero tool calls. Discard the abort line — Phase 7 ignores it (no worker-N id).

Foreground spawn already serializes — no sleep needed before Phase 6b. Skip Phase 6a entirely if plan.run.cache_primer == false.

Phase 6b: Spawn M real workers in parallel (one message per wave of ≤16)

STOP — read this before composing the spawn message.

Workers MUST be spawned foreground (no run_in_background field, or run_in_background=false). "Parallel" here means one assistant message containing the wave's Agent calls — that already runs them concurrently. (For large M, split into consecutive waves of ≤16 calls, one message per wave — see "Required spawn shape" below.) Background spawns are NOT how you parallelize this skill.

Background spawns defeat Phase 6a's primer cache: every worker pays full cache-creation on its first turn (cache_read_input_tokens=0), and the primer's ~15 K tokens are wasted M times over. Two real runs had exactly this symptom — every worker started with first_cr=0.

Before sending the spawn message, audit your draft: every Agent call must have no run_in_background key. If you wrote run_in_background=true, delete it.

Required spawn shape: emit a single assistant message containing the wave's Agent tool invocations — that one message is what runs them concurrently. Sequential spawning (one Agent call per message) serializes the review and is also wrong, but that failure is loud (timing); the background-spawn failure is silent (cost).

Waves when M exceeds the per-message cap. The harness caps the number of Agent calls it will dispatch from a single assistant message (observed: ~20 in Claude Code — a real 25-worker run silently kept only the first 20 and had to spawn the remaining 5 in a second message). So when M > 16, plan the waves up front: split the workers into consecutive waves of ≤16 Agent calls, each wave its own single assistant message. Rules:

• Within a wave: all Agent calls in one message, foreground (no run_in_background) — identical shape to a single-wave run.
• Across waves: wave k+1 is a separate message that can only be sent after wave k's Agent calls all return (a tool-use message ends the turn). Waves are therefore serialized with respect to each other — that is correct and loud; accept it. Do not try to overlap them.
• Never reach for run_in_background=true to fit more workers in one message. More waves, never background — background defeats the primer cache (see the STOP box) and is the cardinal error this skill guards against.
• Cache across waves: the primer prefix has a ~5-minute cache TTL that refreshes on every hit, so back-to-back waves keep hitting it (the 25-worker run confirmed cache_read≈14 K on its second wave). If a later wave will start more than ~5 minutes after the previous one (very large M or slow workers), re-spawn the Phase-6a primer in its own message first to re-warm the prefix before that wave.
• Balance the waves (e.g. M=25 → 13+12, not 20+5) so no wave hugs the cap and the last wave isn't a tiny straggler.
• After every wave has returned, proceed to Phase 7 with the full set of M worker results.

For each worker N ∈ [1..M] (in its assigned wave):

1. Read: ${output_dir}/worker-prompts/worker-N.txt
2. Pass the file contents verbatim as the Agent tool's prompt argument:

The spawn prompt is the single authority. Pass it verbatim — every field is required by the worker's self-check; any deviation triggers worker-N abort: spawn prompt malformed.

Anti-patterns to reject:

• Passing run_in_background=true (see warning above).
• Cramming more than ~16 Agent calls into one message when M is large — the harness silently keeps only the first ~20 and drops the rest. Use balanced waves of ≤16, never background spawns, to cover all M.
• Hand-typing the spawn prompt instead of reading worker-N.txt.
• Inserting Task-related instructions ("first call TaskList", "Assigned task id: "). Workers have no Task tools.
• Editing the rendered prompt before passing it (trimming "redundant" fields, collapsing pass lists).

Phase 7: Wait for Workers and Classify Outcomes

Entry: all M Phase-6 Agent calls have returned. Exit: every cluster has either succeeded or been retried up to the cap; ${output_dir}/findings-index.txt written.

The Phase-6 Agent invocations block until each worker returns. Inspect each worker's return text and apply this classifier in order — first match wins:

If any non-retryable, stop. Otherwise, before re-spawning, clear each retryable worker's prefix-space on disk — the Phase-7 index is built from disk, so a crashed attempt's higher-id stragglers (files the replacement never re-emits) would otherwise be resurrected into the report. Loop over the worker's actual pass_prefixes (from its task metadata), substituting each real prefix for ${pfx} — do not run the command with a literal PREFIX:

# zsh-safe: `find … -delete` never aborts on no-match (an `rm PREFIX-*.md` glob would).
# Replace `PREFIX1 PREFIX2` with the worker's actual space-separated pass_prefixes.
for pfx in PREFIX1 PREFIX2; do
  find "${output_dir}/findings" -maxdepth 1 -type f -name "${pfx}-*.md" -delete
done

Then re-spawn each pending retryable with attempt <= 2 in one parallel block (cap = 2 attempts per cluster). attempt was just incremented to 2 on the first failure, so the guard must admit 2 to allow the single retry — attempt < 2 would block every retry. A second failure increments to 3, which fails <= 2 and ends retries. Replacement workers reuse deterministic finding IDs per prefix, so a cleared prefix-space plus a fresh write yields a consistent shard / coverage / disk set.

Sanity-check + write index

For every provisional complete: cluster, validate the worker-owned shard, coverage file, coverage rows, filed IDs, and claimed finding count against plan.json before marking the task completed. Run one command per completed worker, or validate multiple workers in one command. Both claimed-count forms below are valid; do not pass bare worker-N=N values without either grouping them after a --claimed-count flag or repeating the flag.

python3 "${RUST_REVIEW_PLUGIN_ROOT}/scripts/validate_artifacts.py" "${output_dir}/plan.json" \
  --worker worker-N --claimed-count worker-N=<claimed_count_from_complete_line>

python3 "${RUST_REVIEW_PLUGIN_ROOT}/scripts/validate_artifacts.py" "${output_dir}/plan.json" \
  --worker worker-1 --worker worker-2 \
  --claimed-count worker-1=0 worker-2=3

python3 "${RUST_REVIEW_PLUGIN_ROOT}/scripts/validate_artifacts.py" "${output_dir}/plan.json" \
  --worker worker-1 --worker worker-2 \
  --claimed-count worker-1=0 --claimed-count worker-2=3

If validation exits non-zero, treat the completion as malformed and retryable (classifier row #4): mark the task pending, store the validator output in metadata.abort_reason, set needs_respawn=true, and increment attempt. Missing findings-index.d/worker-N.txt, missing coverage/worker-N.md, missing coverage rows, invalid skipped: rows, filed IDs absent from the shard or disk, and claimed-count mismatches are all malformed completions. After the retry cap, leave the cluster task incomplete and surface the validator output in run-summary.md and the final response. Only validation-clean provisional completions may be TaskUpdated to completed.

Then build the index. The canonical index is the set of finding files actually on disk, not the shard union — building from disk guarantees that a finding written without a matching shard entry (a worker that crashed between its Write and its shard-append, or the single-prefix empty-shard trap the worker prompt warns about) is still picked up by dedup → fp-judge → REPORT/SARIF instead of silently vanishing, and that every index entry resolves to a real file:

# Canonical index = every finding file on disk. `find` never fails on no-match
# (an empty findings/ yields an empty index — the unambiguous "zero findings"
# signal). `sort -u` collapses Phase-7 retry duplicates: replacement workers reuse
# deterministic ids, so the same path appears once.
find "${output_dir}/findings" -maxdepth 1 -type f -name '*.md' 2>/dev/null \
  | sort -u > "${output_dir}/findings-index.txt"

# Reconcile against the per-worker shards: any path on disk but in NO shard is an
# orphan whose worker failed to record it. It is already in the index above (so it
# is NOT dropped) — print it so the bookkeeping gap can be surfaced. Non-fatal.
if [ -d "${output_dir}/findings-index.d" ]; then
  # Reconcile by basename (finding ids are unique), so a path-format difference
  # between the worker `find` and this one (trailing slash, /var↔/private/var)
  # cannot manufacture false orphans. Any basename on disk but in no shard is an
  # orphan whose worker failed to record it.
  comm -13 \
    <(find "${output_dir}/findings-index.d" -maxdepth 1 -type f -name 'worker-*.txt' -exec awk 1 {} + 2>/dev/null | sed 's#.*/##; /^[[:space:]]*$/d' | sort -u) \
    <(find "${output_dir}/findings" -maxdepth 1 -type f -name '*.md' 2>/dev/null | sed 's#.*/##' | sort -u)
fi

The shards stay the per-worker audit trail (validate_artifacts.py checks them) and the dedup-judge's crash-recovery fallback, but they no longer gate what reaches the pipeline. For each orphan basename the reconcile prints, map its <PREFIX> to the owning worker via plan.json and note in run-summary.md that that worker's shard was incomplete — the finding is already in the index (so it is not lost), but the bookkeeping gap should be visible. Still cross-check the index line count against the sum of wrote N worker claims; log mismatches but don't abort.

After task updates and index creation, run TaskList and write ${output_dir}/run-summary.md with:

• resolved parameters (threat_model, severity_filter, finding_scope_root, context_roots, capability flags has_unsafe/has_ffi/has_concurrency/has_async, Cargo manifest status)
• worker outcome table (worker_n, cluster_id, claimed finding count, shard line count, coverage-file path (coverage/worker-{N}.md), task status, retry/abort state)
• findings-index.txt line count and any mismatch against worker claims
• judge status once Phase 8 finishes, or the reason a judge was skipped/failed

If any Phase-5 cluster task is not completed — or any worker returned a complete: line carrying the truncated at hard cap token (it hit the tool-call cap before searching every pass; its coverage file will show one or more cleared (NOT SEARCHED — truncated at hard cap) rows) — include it prominently in run-summary.md and the final response. A hard-cap-truncated worker is marked completed for ledger purposes but is a partial result: do not let that completed status hide the incomplete coverage behind a successful report.

Always run Phase 8 even on zero findings — both judges short-circuit on an empty index: dedup-judge writes a minimal no-op dedup-summary.md, and fp-judge writes empty REPORT.md/REPORT.sarif so SARIF consumers get a stable artifact set.

Phase 8: Judge Pipeline (sequential, dedup → fp+severity)

Entry: findings-index.txt exists. Exit: dedup-judge and fp-judge have returned; dedup-summary.md, fp-summary.md, REPORT.md, and ideally REPORT.sarif are written.

Each judge's full protocol is its system prompt (agents/rust-review-{dedup,fp}-judge.md); spawn prompts pass only per-run variables. Do not reference prompts/internal/judges/ — those files don't exist.

STOP — these two judges run in SEQUENCE, not in parallel. Unlike the Phase-6b workers (which you spawn as M Agent calls in one message precisely because that runs them concurrently), the judges have a hard data dependency: fp-judge must see the merged_into / also_known_as annotations dedup-judge writes, and it only skips files already carrying merged_into. If you emit both Agent calls in one message they run concurrently — fp-judge reads findings before any merge annotations exist, judges every duplicate as a separate primary, and (because dedup-summary.md doesn't exist yet) trips its "dedup did not run" fallback, producing an inflated, duplicated REPORT.md/SARIF.

Spawn dedup-judge in its own assistant message, wait for its dedup-judge complete: (or abort:) return, then spawn fp-judge in a separate message. Before composing the fp-judge spawn, confirm dedup finished — Bash: test -f ${output_dir}/dedup-summary.md must succeed (or you saw the dedup complete: token). Never put both judge Agent calls in the same message.

1. First message — Agent(subagent_type="rust-review:rust-review-dedup-judge", description="Dedup judge", prompt=f"output_dir: {output_dir}"). Wait for its return and classify it (below) before continuing.
2. Then, in a separate message — Agent(subagent_type="rust-review:rust-review-fp-judge", description="FP + severity judge", prompt=f"output_dir: {output_dir}\nsarif_generator_path: {sarif_generator_path}") — resolve sarif_generator_path to ${RUST_REVIEW_PLUGIN_ROOT}/scripts/generate_sarif.py.

Judge failure handling. Same shape as Phase 7's classifier, applied to judge return text:

• … complete: → success.
• … abort: → non-retryable for that judge. Surface the abort line plus ls -l ${output_dir}/findings-index.txt, then still run Phase 8b (its SARIF + REPORT.md safety net guarantees the artifact set even when a judge aborts — see Phase 8b's "fp-judge returned, or the run aborted early" entry), and stop without spawning further judges. "Stop" means do not continue the judge pipeline — it does not mean skip Phase 8b.
• No complete: (help message / error / question) → retryable once. SendMessage(to=<agentId>, …) rather than a fresh spawn (the agent already paid the protocol-parse cost). Include the explicit finding paths from findings-index.txt. If the second try still fails, surface the transcript and continue to Phase 8b.

Phase 8b: Report safety net (SARIF + REPORT.md)

Entry: fp-judge returned, or the run aborted early. Exit: ${output_dir}/REPORT.sarif and ${output_dir}/REPORT.md both exist.

test -d "${output_dir}/findings" && python3 "${RUST_REVIEW_PLUGIN_ROOT}/scripts/generate_sarif.py" "${output_dir}"

Run the SARIF generator unconditionally whenever findings/ exists — it is idempotent (full overwrite), emits results: [] for zero-survivor runs, and handles partial runs (findings without fp_verdict are emitted as LIKELY_TP, exempt from the severity_filter since their severity was never judge-validated, and marked unjudged: true / severity_validated: false with an [UNVALIDATED SEVERITY — not judged] message prefix — so an inferred severity guess can never silently drop them under a medium/high filter). Always overwriting protects against an fp-judge that crashed mid-write and left a corrupt REPORT.sarif on disk.

If the generator prints a WARNING: skipped N … line on stdout (it also records invocations[].properties.skipped_findings in the SARIF and a warning notification per dropped file), one or more finding files were unreadable or had no parseable frontmatter and were excluded from the report. This is a dropped result — surface it prominently in run-summary.md and the final response with the count and paths, the same way a non-completed cluster task is surfaced. Do not let the otherwise-clean SARIF hide the loss.

Then guarantee REPORT.md exists. Unlike SARIF (mechanical), REPORT.md is the fp-judge's curated artifact, so do not overwrite a judge-written one. (The fp-judge writes REPORT.md with a Bash heredoc, not the Write tool, because the harness blocks the Write tool for subagent report files — do not "fix" the judge by re-mandating Write. The orchestrator is the main agent and is not subject to that block, so its own Write below works.) Check for it, and if it is missing (the judge crashed, even its Bash-heredoc write failed, or it returned the report as chat text instead of writing the file), the orchestrator writes REPORT.md itself rather than failing the run:

• If the fp-judge returned the report body in its transcript, Write that text verbatim to ${output_dir}/REPORT.md.
• Otherwise synthesize it from the on-disk findings: take the survivor primaries (fp_verdict ∈ {TRUE_POSITIVE, LIKELY_TP}, no merged_into; if the judge never ran, treat a finding with no fp_verdict as a survivor) listed in findings-index.txt, apply severity_filter from context.md to judged survivors only — unjudged findings (no fp_verdict) are included regardless of filter and rendered under an Unvalidated (severity not judged) section with a [UNVALIDATED SEVERITY — not judged] label, mirroring the SARIF behavior so a strict filter never silently drops them — and Write a REPORT.md mirroring the fp-judge template — YAML frontmatter (stage: final-report, threat_model, severity_filter, total_primaries, reported_findings), a severity-distr

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