Conciseness

The 260-line body includes explanations Claude already knows — RPO/RTO definitions, the 3-2-1 rule, and object-store versioning/replication basics — and restates the same themes repeatedly (immutability against ransomware appears in Question 4, Step 3, File storage backups, and Failure patterns; 'untested backups' appears three times). Aphoristic filler lines ('If you can't list it, you can't protect it', 'Then you'll be busier during the disaster') add tokens without adding guidance. This fits anchor 3 ('mostly efficient but includes some unnecessary explanation or could be tightened') rather than 4, where over-explanation would be only minor.

Actionability

Concrete, specific instruction-only guidance: tiering definitions, an RTO-to-architecture mapping table, a 7-step workflow with explicit checklists (Step 3's frequency/retention/immutability list), named storage features to enable (versioning, replication, object lock), drill types with recommended cadence, a defined output format, and a fillable runbook template reference. Scored 4 rather than 5 because some guidance stays high-level (e.g., 'How to detect the disaster (cross-reference monitoring)') and restore commands are necessarily left system-specific, leaving minor gaps.

Workflow Clarity

The 7-step workflow (inventory, set targets, verify architecture, document runbook, run drill, document results, schedule next drill) is clearly sequenced with explicit validation checkpoints: the inventory's 'Tested?' column, 'Tested restore procedure' as a hard requirement, 'How to verify the restore worked' in the runbook, and Step 6's comparison of actual vs. target RPO/RTO. It closes a genuine feedback loop ('If the actual RTO was 6 hours when the target was 1 hour... Either fix the gap or revise the target') and provides checklists, matching the anchor-5 criteria; it is above anchor 4 because validation is explicit throughout, not just mostly present.

Progressive Disclosure

The body is well-sectioned and its single bundle file (references/restore-runbook-template.md) is real, one level deep, clearly signaled, and described ('Fillable template for a restore runbook, covering detection, authorization, steps, verification, and rollback') — the template is appropriately externalized. However, the 260-line body carries substantial material (Special topics, Failure patterns) that could live in references, so it is 'good structure; most content appropriately placed; minor organization gaps' (anchor 4) rather than the lean overview-plus-references split of anchor 5.

Specificity

Lists multiple specific concrete actions — 'Plan and run backups, set recovery objectives, and run disaster recovery drills', plus designing backup architecture, deciding backup frequency, and planning for full-region or platform outages. Coverage of the DR-planning domain is comprehensive, matching the anchor 'multiple specific concrete actions; comprehensive coverage'.

Completeness

Explicitly answers 'what' (first sentence enumerates the skill's actions) and 'when' ('Use this skill when defining RPO/RTO targets, designing backup architecture... or running a restoration drill') with concrete trigger phrases. This is a direct match for the anchor-5 example structure; it is above anchor 4 because both what and when are fully explicit rather than merely present.

Trigger Term Quality

Trigger coverage includes the core terms (backup, restore, RPO, RTO, disaster recovery), synonyms (DR, business continuity, recovery drill, ransomware planning), and natural user phrasings like 'what if the database is gone' and 'what if our hosting goes down'. This is comprehensive natural-term coverage including synonyms, matching the anchor for 5; it does not fit anchor 4 ('a few natural terms missing') since no common variation is absent.

Distinctiveness Conflict Risk

The RPO/RTO/DR-drill niche is clear and mostly distinct, but the clause 'Also triggers when an incident reveals a gap in restoration capability' and the bare trigger 'restore' create minor overlap risk with closely related skills such as incident-response and routine restore requests. This fits anchor 4 ('mostly distinct; minor overlap risk with closely related skills') better than 5, since a neighboring incident-response skill could plausibly fire on the incident-gap trigger.