Conciseness

The ~20-line body is pure routing: one classification directive ('Identify the memory initiator, transport, required privilege, isolation boundary, and observable artifacts before classifying a technique as DMA') plus per-file pointers, each with a one-line scope. Nothing explains concepts Claude already knows; every token earns its place, matching anchor 5.

Actionability

Guidance is concrete and specific: each routing bullet names the exact subtopics a file covers ('for TLPs, configuration space, programmable endpoints, and emulation limits', 'for separating ACPI advertisement, Windows policy, live unit state, and per-requester coverage'), and all cited files exist with substantive content. It stays below anchor 5 because the central directive names five factors to identify but leaves how they combine into a DMA classification entirely to the references — no decision points or worked example in the body.

Workflow Clarity

There is an explicit ordering rule ('Identify the memory initiator... before classifying a technique as DMA') followed by unambiguous topic-to-file routing, so the navigation workflow is clear; no validation steps are needed since nothing here is destructive or batch. It falls short of anchor 5 because the analytical sequence itself — how the five identification factors resolve into a classification and which reference to consult when several paths apply — is not sequenced in the body.

Progressive Disclosure

This is the anchor-5 pattern: a lean overview in SKILL.md with nine clearly signaled, one-level-deep references, each annotated with a scope line so navigation is trivial. All referenced paths resolve to real, substantive files, and the references only cross-link siblings (still one hop), so there is no nesting or buried content.

Specificity

Names the domain precisely and lists several concrete analysis targets — 'PCIe DMA threats, host-mediated memory acquisition, FPGA behavior, and IOMMU defenses' — with only minor gaps in coverage. It falls short of anchor 5 because a single verb ('Analyze') covers a list of topics rather than multiple distinct concrete actions (extract, fill, merge, convert), and above anchor 3 because the coverage of the niche is broad and every object named is technically specific.

Completeness

Both parts are present: a clear 'what' ('Analyze PCIe DMA threats, host-mediated memory acquisition, FPGA behavior, and IOMMU defenses') and an explicit 'when' ('Use when the memory initiator or device boundary matters'), plus sibling-skill routing ('use kernel security for host-only mechanisms'). It sits below anchor 5 because the trigger is phrased as an abstract condition rather than concrete user-mention phrases, and above anchor 3 because the 'when' clause is explicit and genuinely discriminating rather than missing or weakly implied.

Trigger Term Quality

Good keyword coverage with natural terms users would actually say in this niche: 'PCIe DMA', 'IOMMU', 'FPGA', 'memory acquisition', 'memory initiator'. A few natural terms are missing — e.g. 'DMA attack', 'Thunderbolt', 'USB4', 'VT-d', 'pcileech' — which appear in the skill's own reference files but not in the description, keeping it below anchor 5.

Distinctiveness Conflict Risk

Clear niche with distinct triggers — PCIe DMA / device-boundary attacks — and minimal conflict risk; it even disambiguates against the adjacent skill ('use kernel security for host-only mechanisms'), actively routing away overlaps. This matches anchor 5 and is clearly above anchor 4's 'minor overlap risk'.