Conciseness

The ~30-line body is lean and earns its tokens: decision logic with exact state checks ("If it reports 'is closed' or 'is open', note the state"), the exact action format, one compact trajectory example, and three short operational notes. It never explains concepts Claude already knows and has no padding, matching anchor 5.

Actionability

Concrete, copy-paste-ready commands are given ("Action: open {recep}", "Action: close {recep}", "Action: open fridge 1") with a worked trajectory example covering the common cases. It stops short of anchor 5 due to a minor gap: the receptacle ID convention (the '1' in 'fridge 1') is used but never explained, so guidance is mostly executable with a small gap.

Workflow Clarity

The Core Decision Logic is a clearly sequenced three-step process (check state → choose action per goal with explicit branches → execute in exact format), with a validation checkpoint ("Always verify the receptacle state from the latest observation before acting") and an explicit error-recovery feedback loop ("If 'Nothing happened' is observed... re-check and adjust"). This is a simple, non-destructive skill that nonetheless includes feedback loops, matching anchor 5.

Progressive Disclosure

The body is short and well-sectioned, and the single reference (references/state_diagrams.md) is one level deep — but the pointer is vague: "For detailed state diagrams and edge cases, see the reference documentation" names neither the file nor its path. Additionally, the actual reference file contains only a heading ("## Primary State Transitions") with no content, so the promised detail is not delivered. This fits anchor 3 (references present but not clearly signaled) rather than anchor 4 (references mostly clear).

Specificity

The description names the domain and concrete actions — "opens or closes a receptacle (like a fridge, cabinet, or microwave)" plus state-based action selection ("decides the appropriate 'open' or 'close' action based on the receptacle's current state") — with only minor gaps in coverage phrasing. It exceeds anchor 3 (which expects just 1-2 actions and no comprehensiveness) but falls short of anchor 5's comprehensive multi-action coverage.

Completeness

Both questions are answered explicitly: the 'what' ("opens or closes a receptacle... to access its interior or secure it") and the 'when' with concrete trigger conditions ("It should be triggered when an object needs to be placed inside/retrieved from a closed container, or when an open container should be closed (e.g., for energy efficiency or task cleanliness)"). This matches anchor 5's clear what + when with concrete triggers; anchor 4 would require the 'when' to be less explicit than it is.

Trigger Term Quality

Good natural keyword coverage: "fridge, cabinet, microwave", "placed inside/retrieved from a closed container", "closed", "energy efficiency" — phrases a user or planner would naturally use. A few natural variations are missing (e.g., 'open the fridge', 'shut', object synonyms), keeping it below anchor 5.

Distinctiveness Conflict Risk

The skill occupies a clear niche (only open/close receptacle actions) with distinct triggers, but the trigger "an object needs to be placed inside/retrieved from" overlaps with put/take skills that would also fire on container goals — minor overlap risk with closely related skills per anchor 4. Not anchor 5 because of that overlap with adjacent object-manipulation skills.