Conciseness

The body is lean throughout — a routing table, a terse five-step pattern, compact code, and table-formatted anti-patterns with no padding. The Overview earns its tokens by stating the non-obvious unifying insight ('ships the same hermetic-test mechanism under a different name'), not by explaining concepts Claude already knows.

Actionability

The routing table gives the exact offline switch and arm-pinning API for each vendor ('localMode: true', 'set_forced_decision', "authorizationKey: 'localhost'", 'bootstrap', 'is_development_mode'), and the worked Optimizely example is complete, executable Python covering the common case. Each anti-pattern row pairs a failure with a concrete fix.

Workflow Clarity

The shared pattern is a clearly sequenced five-step checklist with explicit validation built in ('Determinism - the same user ID gets the same arm', 'Distribution - across many user IDs, more than one arm actually occurs'), and the anti-patterns table maps each failure mode to its fix. Not 4: no validation gaps remain — the two integrity tests and assert-on-keys-not-IDs rule are explicit checkpoints.

Progressive Disclosure

SKILL.md is a genuine overview holding only the vendor-neutral pattern, with all seven bundle files verified to exist and directly linked one level deep (including the optimizely-recipes.md and split-io-example.md secondaries). Cross-links between references are lateral sibling links, so navigation never nests.

Specificity

'Initializes the SDK offline from a committed config fixture, pins each test to an arm and checks assignment integrity' lists multiple concrete actions covering the skill's full scope. Not 4: there are no minor gaps — init, pinning, and integrity checking are the complete workflow.

Completeness

'Use when code instrumented with ... needs tests' is an explicit when-clause with concrete trigger conditions, and the what is fully explicit in third person ('Initializes', 'pins', 'checks'). Both halves are answered clearly and concretely.

Trigger Term Quality

Vendor names (Statsig, Optimizely, Split.io, Amplitude Experiment, VWO) plus the natural phrase 'needs tests' give strong keyword coverage, but generic synonyms a user might say — 'feature flag', 'A/B test', 'experimentation' — are absent. Not 5: common natural variations are missing; not 3: the vendor terms are exactly what affected users say.

Distinctiveness Conflict Risk

Naming five specific experimentation SDKs carves out a clear niche with minimal conflict risk — a generic testing or analytics skill would not match these triggers. Not 4: no meaningful overlap with closely related skills; the vendor list plus 'offline from a committed config fixture' is unambiguous.