Conciseness

Lean and dense throughout: every token carries repo-specific knowledge Claude cannot infer — 'experiment: { mode: 'auto' }', 'IWorkbenchAssignmentService.getTreatment<T>(name)', 'experiments.override.<treatment name>', 'monacoworkbench/experimentTrigger', the once-per-window semantics, the agent-host forwarding caveat. No general concepts (what A/B testing is, how telemetry works) are re-explained, and the one rationale sentence ('Dilution only costs statistical power, while a biased trigger gives wrong results') directly justifies the decision rules that follow, so it earns its place.

Actionability

Fully concrete, executable guidance: exact schema properties to add, exact API calls with generic types, an exact user-settings override string, named helper functions with copy-paste-ready call signatures ('logSettingExperimentTrigger(telemetryService, MY_SETTING_ID)'), a correctly-ordered code example, named test service 'TestExperimentTriggerTelemetryService', and named code anchors (experimentTrigger.ts, AgentHostGitStateService, chat.agentMerge.enabled). This matches the level-5 anchor for an instruction skill with concrete, specific guidance throughout.

Workflow Clarity

The processes are clearly sequenced with explicit checkpoints: choose the control mechanism (setting vs. treatment, with the decision criterion 'users could reasonably choose the behavior themselves'), decide whether a trigger applies (concrete in/out cases), fire it with a decision table plus an annotated code example showing arm-independent ordering, then validate — 'Test each trigger in every arm with TestExperimentTriggerTelemetryService'. The pitfalls list ('Find every place where the setting or treatment changes behavior') acts as a checklist, and 'start a new experiment iteration' after moving a trigger is corrective guidance, matching the level-5 anchor.

Progressive Disclosure

The skill is self-contained at ~63 lines with no bundle files, well-organized under clear sections ('Controlling behavior', 'Trigger events', 'When to use one', 'When to fire it'), and its single reference — the source-file link to experimentTrigger.ts — is well-signaled and one level deep. Nothing is inlined that clearly belongs in a separate file at this scale, so navigation is easy and content placement is appropriate, matching the level-5 anchor.

Specificity

Names several concrete actions in a specific domain — 'adding, changing, or reviewing a VS Code A/B experiment', 'an experiment-controlled setting', 'a treatment read with the assignment service', 'log an `experimentTrigger` event for a triggered ExP scorecard' — going beyond the 1–2 actions of the level-3 anchor. Not a 5 because coverage has minor gaps: the skill also guides trigger placement and testing, which the description does not hint at.

Completeness

The 'when' is explicit and concrete ('Use when adding, changing, or reviewing a VS Code A/B experiment… and when deciding whether and where to log an `experimentTrigger` event'), satisfying the Use-when requirement. The 'what' is conveyed only through the enumerated tasks rather than stated as its own capability statement, so it does not clearly match the level-5 anchor where both are explicit; it is well above the level-3 anchor where 'when' is missing or weakly implied.

Trigger Term Quality

Good natural keyword coverage — 'experiment', 'A/B experiment', 'treatment', 'scorecard', 'experimentTrigger', 'VS Code' — phrases a repo contributor would actually say. A few natural terms are missing (e.g., 'feature flag', 'flight', 'telemetry trigger'), so it falls just short of the comprehensive-synonym coverage of the level-5 anchor.

Distinctiveness Conflict Risk

A clear niche with distinct triggers — VS Code A/B experiments, ExP scorecards, the experimentTrigger event — that no generically-described skill would overlap with. This matches the level-5 anchor ('clear niche with distinct triggers; minimal conflict risk').