Detection signals: which reference to consult

Route from what the managed code is doing to the reference that covers it. The point is progressive disclosure — open a section only when the code under scan touches that area. Match on what the code does, not just a token; then apply decision-framework.md (hot vs cold path, complexity, the two-proof gate) before acting. A signal is a reason to look, not a verdict — a match on a cold path is recorded briefly and dropped.

Grep starting points to sweep the managed binding (binding/**, source/**; never *.generated.cs or externals/skia/**) are in each hot-path/bcl-pattern reference.

When the managed code does this	Consult
A property/method on a blittable struct (SKMatrix/SKRect/SKPoint/SKColorF) calls SkiaApi.sk_* to compute a few float ops — invert, concat, map point/vector/rect/radius	hot-paths/geometry-math.md
SKColor/SKColorF parse/format/convert: Parse/TryParse, byte.TryParse+NumberStyles, new string(...), FromHsl, missing ReadOnlySpan<char> overload	hot-paths/color.md, bcl-patterns/strings-and-spans.md
A getter wraps a child native object every access (GetObject/OwnedBy with no cache); a Dictionary/ConcurrentDictionary created without capacity; HandleDictionary/lock on a hot registration path	hot-paths/handles-and-collections.md, bcl-patterns/collections.md
A for/foreach loop containing SkiaApi.sk_* per element (glyph paths, uniform enumeration); HarfBuzz Shape; AllocHGlobal/StringToHGlobal/Encoding.GetBytes per text call; GetEncodedText	hot-paths/text-and-fonts.md, bcl-patterns/interop-and-marshalling.md
Pixel/scanline copy element-by-element; SKBitmap.Bytes/Pixels .ToArray(); SKColor[]↔uint*; blittable reinterpret opportunities	hot-paths/pixels-and-images.md, bcl-patterns/memory-and-buffers.md
new byte[]/new char[]/new IntPtr[] scratch buffers, .ToArray() on a hot path, a large blittable struct passed by value	bcl-patterns/memory-and-buffers.md, repo-helpers.md (Utils.RentArray, RentHandlesArray)
IndexOfAny(char[])/manual char-set scans in a parser/tokenizer (SVG path data), repeated membership checks	bcl-patterns/collections.md (SearchValues), bcl-patterns/strings-and-spans.md
A P/Invoke declaration or blittable-signature concern, [MarshalAs], bool/char marshalling, LibraryImport/DllImport	bcl-patterns/interop-and-marshalling.md
System.Numerics.Vector*, Vector128/Vector256, MathF, manual SIMD, batch math	bcl-patterns/numerics-and-simd.md
A one-line forwarding wrapper or nibble/parse helper the JIT should inline; a non-sealed internal type; an expensive computation (shaping, path measure) recomputed with no cache	bcl-patterns/numerics-and-simd.md, hot-paths/text-and-fonts.md
StringBuilder, hand-rolled pooling, a locally-reimplemented ArrayPool/throw-helper	repo-helpers.md (reuse the shared helper)

Notes:

• One line can match several signals — open each relevant section and pick the highest-leverage, lowest-complexity fix.
• Confirm the code is on a hot path (the SkiaSharp hot list in decision-framework.md) before proving a change. If it's cold, note it and move on.
• Some per-element native loops have no managed-only bulk alternative (they'd need a new bulk C API under externals/skia/**). Those are issue-only — see the split in hot-paths/text-and-fonts.md.