Conciseness

The body is dense and lean with no padding: every line carries repo-specific nuance (e.g. 'Read IsHardwareAccelerated and Count directly; don't cache them to locals') and it never explains concepts Claude already knows, matching the 'lean and efficient; every token earns its place' anchor rather than the 'could be tightened' (2) level.

Actionability

Concrete, executable guidance throughout — named APIs (Vector128.Create(span), CopyTo, LoadUnsafe(ref T, nuint elementOffset), MemoryMarshal.GetReference, ConditionalSelect, BoundedMemory.Allocate<T>) and exact commands/env vars (DOTNET_EnableAVX2=0, DOTNET_EnableHWIntrinsic=0) — matching 'fully executable... copy-paste ready' rather than the 'pseudocode/missing details' (2) level.

Workflow Clarity

Multi-step processes are clearly sequenced with validation checkpoints: the Testing checklist toggles acceleration via env vars and guards OOB reads with BoundedMemory, and the Review checklist is ordered 'verify in priority order' with an explicit feedback note ('Ask for the missing test rather than just rejecting') — meeting the 'clear sequence with explicit validation steps' anchor rather than 'checkpoints missing/implicit' (2).

Progressive Disclosure

A single well-organized overview file with one-level-deep, clearly signaled references (official .NET SIMD doc, docs/coding-guidelines/vectorization-guidelines.md, .github/copilot-instructions.md, the BoundedMemory source, and PR links); no bundle files exist to require deeper structure, matching the 'clear overview with well-signaled one-level-deep references' anchor rather than 'content that should be separate is inline' (2).

Specificity

Names the domain ('SIMD / hardware-intrinsics code in dotnet/runtime') and lists multiple concrete actions: 'vectorizing a scalar algorithm', 'writing or reviewing code that uses Vector128/Vector256/Vector512, Vector<T>', 'validating remainder handling, load/store safety, and hardware-acceleration fallbacks' — matching the 'lists multiple specific concrete actions' anchor.

Completeness

Explicitly answers both what ('Guidance for writing and reviewing SIMD / hardware-intrinsics code... validating remainder handling, load/store safety') and when via explicit triggers ('USE FOR: ...', 'DO NOT USE FOR: ...'), matching the 'clearly answers both what AND when' anchor rather than the 'when only implied' (2) level.

Trigger Term Quality

Covers the natural terms a dotnet/runtime contributor would say — 'vectorizing a scalar algorithm', 'Vector128/Vector256/Vector512', 'Vector<T>', 'platform intrinsics', 'remainder handling', 'SIMD' — with good breadth; not the 'only some relevant keywords' (2) level and clearly above generic jargon-only (1).

Distinctiveness Conflict Risk

A clear niche (SIMD/vectorization in dotnet/runtime) with an explicit 'DO NOT USE FOR' routing general perf work to performance-benchmark and non-vectorized review to code-review, making wrong-skill triggering unlikely — above the 'could still overlap' (2) level.