Conciseness

The tables are dense and information-rich, but the opening Wikipedia quotation ('a technique that is used in the development and testing of complex real-time embedded systems'), the meta-commentary on citation availability ('The terms MIL / SIL / PIL / HIL are not in Wikipedia's HIL article'), and repeated 'Cite by stable ID' asides in table rows pad the document with explanation Claude does not need.

Actionability

Concrete, specific guidance throughout: an executable-shape CAPL testcase (Test_Brake_Latency with TestWaitForSignalMatch), a VeriStand real-time sequence, precise standard clauses (IEC 61508-3 Table A.5, DO-178C §6.4.4), file formats (.nivssdf), and anti-patterns each paired with a concrete fix. Minor gaps only - no complete end-to-end runnable scenario - so anchor 4 rather than 5.

Workflow Clarity

A reference skill with no multi-step process to sequence; sections are well-ordered for the stated use cases (scoping -> HIL pattern -> V-cycle stages -> vendors -> protocols -> fault patterns -> standards -> evidence -> anti-patterns) and include checkpoints such as 'each scenario must have machine-checkable assertions' and 'the simulator must monitor and FAIL on missed-deadline'. Not 5 because the 'reading a vendor HIL report' use case is never given an explicit step sequence.

Progressive Disclosure

A single ~240-line file with 13 clear section headers but no bundle files at all - references/, scripts/ and assets/ do not exist - so the vendor-stack, bus-protocol and fault-pattern tables are fully inlined in SKILL.md instead of being split into one-level-deep reference files. Good structure, but content that should be separate is inline, matching anchor 3 rather than 4.

Specificity

Names two concrete actions ('scoping an embedded hardware-in-the-loop (HIL) rig', 'reading an automotive, aerospace or industrial HIL report') backed by a comprehensive enumeration of covered capabilities (MIL/SIL/PIL/HIL stages, NI/dSPACE/Vector/Speedgoat stacks, CAN/LIN/FlexRay/Ethernet emulation, fault injection, ISO 26262/DO-178C/IEC 61508 evidence). Matches anchor 4 - several specific capabilities with minor gaps - rather than 5, which expects a fuller list of distinct actions, and is clearly above anchor 3's '1-2 concrete actions, not comprehensive'.

Completeness

The 'when' is explicit and concrete ('Use when scoping... or reading an automotive, aerospace or industrial HIL report'), and the 'what' is conveyed by the colon-delimited enumeration of covered topics rather than an explicit capability verb. Falls at anchor 4 ('both what and when; one could be more explicit') rather than 5, and is above anchor 3 since the when-clause is explicit, not merely implied.

Trigger Term Quality

Comprehensive natural-term coverage: the spelled-out plus acronym pair 'hardware-in-the-loop (HIL)', stage names 'MIL, SIL, PIL and HIL', vendor names 'NI, dSPACE, Vector and Speedgoat', protocols 'CAN, LIN, FlexRay', and 'fault injection', 'ISO 26262, DO-178C and IEC 61508' - exactly the terms a practitioner would say when needing this skill. Matches anchor 5's 'comprehensive coverage of natural terms including synonyms'.

Distinctiveness Conflict Risk

Occupies a clear niche - embedded HIL rig scoping and vendor HIL report reading in automotive/aerospace/industrial domains - with triggers (HIL, MIL/SIL/PIL, vendor and standard names) that are unmistakable and unlikely to fire for generic testing or documentation skills. Matches anchor 5's 'clear niche with distinct triggers; minimal conflict risk'.