Conciseness

Nearly every sentence is task-specific policy (tool calls, paths, dispositions) with no padding explaining concepts Claude already knows, which keeps it above the verbose anchors. However, the same rules are restated repeatedly — compact-mode 'no per-finding reports / every candidate gets a disposition' appears in four sections (workflow step 9, Output Contract, Hard Rules, and the compact-mode section), and the large-repository proportionality rules appear in overlapping variants three times — so it could be tightened considerably. This matches 'Mostly efficient but includes some unnecessary explanation or could be tightened', not a 2, since nothing is generic filler.

Actionability

Guidance is fully specified to copy-paste readiness: exact tool call signatures ("list_codex_security_candidates({ scanId, cursor?, limit? })", "record_codex_security_candidate_validations({ scanId, validations: [{ candidateId, validation }] })"), exact debugger invocations (gdb: "-q -batch -ex run -ex bt -ex quit"; lldb: "-b -o run -o bt -o quit"), concrete artifact paths ("<discovery_dir>/validation_artifacts/<candidate_id>/"), exact disposition enums, and a complete output field list. Per the rubric's instruction-skill note, concrete specific guidance substitutes for code, and it is fully executable.

Workflow Clarity

The 9-step workflow is clearly sequenced with explicit checkpoints: a per-candidate validation rubric created before work, a condition-gated method cascade in step 3, proof-gap documentation when validation fails (step 7), and mandated per-candidate receipts in step 9. Error-recovery loops are present ('diagnose the failure enough to know whether a targeted build... can still exercise the original code'; 'check process status, recent logs... before stopping or weakening validation'), and checklists are required in both input (rubric with up to five criteria) and output ('rubric checklist with `- [x]` or `- [ ]` items'). This matches the 5 anchor; the only blemish — steps 4-5 partially restating step 3's cascade — is a redundancy issue scored under conciseness, not a sequence gap.

Progressive Disclosure

The one bundle reference is real, well-signaled, one level deep, and substantive: 'references/validation-guidance.md' (122 lines) contains exactly the three sections the body promises (instance-preserving validation rules, validation checklist, confidence guidance), and the body delegates storage policy and static assessment to clearly-described shared family files. Minor gaps keep it at the 4 anchor rather than 5: the `../../references/scan-artifacts.md`, `artifact-storage.md`, and `static-finding-assessment.md` citations (repeated several times) resolve outside this bundle and cannot be verified from it, and the dense 20-line Hard Rules block is more policy detail inline than a true overview layer.

Specificity

The description names the domain ("validation phase of a security scan", "candidate security findings") and one concrete action — "determine whether one or more candidate security findings are valid" — but lists no supporting concrete actions (e.g., PoC reproduction, valgrind/ASan, source-to-sink tracing). This matches the anchor 'Names domain and 1-2 concrete actions, but not comprehensive'; it is above a 2 because the stated action is concrete rather than generic, and below a 4 because no additional specific actions or outputs are named.

Completeness

Both parts are explicit: the 'when' is concrete and two-pronged ("Use when Codex is already in the validation phase of a security scan or the user explicitly asks to determine whether one or more candidate security findings are valid") plus a negative trigger, and the 'what' is stated clearly but thinly — a single action with no mention of validation methods or outputs. It sits between the 4 anchor ('when' could be more specific) and the 5 anchor (comprehensive what AND when), closer to 5 on 'when' but pulled down by the minimal 'what'.

Trigger Term Quality

Natural phrases a user in this workflow would say are present: "security scan", "validation phase", "determine whether... findings are valid", plus scan-type variations ("PR, commit, branch, patch, or repository scans") that aid routing. It falls just short of comprehensive because common synonyms such as "verify", "confirm", "triage", or "false positive" are absent.

Distinctiveness Conflict Risk

The description carves out a clear niche with an explicit exclusion — "Do not use as the primary trigger for full PR, commit, branch, patch, or repository scans" — which directly prevents mis-triggering for the sibling discovery/full-scan skills. This clearly matches 'Clear niche with distinct triggers; minimal conflict risk'.