Conciseness

The ~30-line body is lean and directive with zero filler: every step ("Project outputs after consuming them: retain decisions, evidence, errors..."), anti-pattern, and reference earns its place, and nothing explains concepts Claude already knows. Not a 4 because there are no over-explanation instances to trim.

Actionability

As an instruction-only skill it gives specific, executable guidance — exact lists of what to carry ("goal, active slice, authority, decisions, blockers, evidence links, and next action"), what to measure ("cache reads, replayed input, and total actor cost"), and explicit prohibitions. It falls short of 5 because steps like "Inspect host capabilities" and "Bound context at host-supported boundaries" state what to do without any method for doing it.

Workflow Clarity

The five steps (Inspect → Project → Bound → Compact → Measure) are clearly sequenced with guardrail conditions ("Compact only when useful and supported", "never discard source evidence") and a measurement/verification step. It is not a 5 because there is no explicit error-recovery feedback loop (e.g., what to do when measurement reveals replayed input or a compaction failure).

Progressive Disclosure

The body is a clear overview whose details are appropriately split into three real, one-level-deep reference files (verified: references/compaction.md, references/masking.md, references/implementation.md all exist, contain substantive content, and reference no further files), listed with descriptive labels for easy navigation.

Specificity

"Manage context and prompt-cache costs without losing task state" names the domain and one governing action with a concrete constraint, but does not enumerate several distinct concrete actions the way the anchor-4 example does ("Extracts text..., fills forms, converts pages...").

Completeness

It explicitly answers both "what" ("Manage context and prompt-cache costs without losing task state") and "when" ("Use for context management, orchestration cost, token budgets, large tool outputs, cache misses, or long-running conversations") with concrete trigger phrases, matching the anchor-5 example structure. It is not a 4 because the 'when' clause is explicit and specific rather than vague.

Trigger Term Quality

"context management, orchestration cost, token budgets, large tool outputs, cache misses, long-running conversations" gives good natural-keyword coverage, but common variations users would say ("reduce tokens", "trim context", "summarize history") are absent from the description itself.

Distinctiveness Conflict Risk

The prompt-cache/orchestration-cost niche is mostly distinct with domain-specific triggers, but "context management" and "large tool outputs" are broad enough to overlap with summarization or output-management skills, so it does not reach the minimal-conflict anchor 5.