diff --git a/docs/roadmap/implementation-status.md b/docs/roadmap/implementation-status.md
index b41d519..c8cb8d7 100644
--- a/docs/roadmap/implementation-status.md
+++ b/docs/roadmap/implementation-status.md
@@ -10,10 +10,11 @@ lane, the core libraries, the initial GeoTIFF window reader, the metadata
 authoring library, and the first format-specific plugin are built and tested.
 The optional libtiff backend now decodes Deflate, LZW, and PackBits windows
 through the RandomAccessSource client-I/O boundary. Uncompressed floating-point
-predictor windows are decoded in the reader, while broad read planning and converter
-sources are not implemented yet. The initial GeoTIFF-to-regular-grid mesh slice is now
-connected and tested, including its interactive vertex ceiling, and no release
-has been tagged.
+predictor windows are decoded in the reader, and read planning, memory budgets,
+and tile-boundary cancellation are covered by tests. Converter sources are not
+implemented yet. The initial GeoTIFF-to-regular-grid mesh slice is now connected
+and tested, including its interactive vertex ceiling, and no release has been
+tagged.
 
 Status words, from
 [MODULE_README_CONTRACT.md](../contributing/MODULE_README_CONTRACT.md):
@@ -128,8 +129,8 @@ Detail in [phase-1-raster-core.md](phase-1-raster-core.md).
 | `ReadScanlines` | implemented |
 | Read planning and range coalescing | implemented |
 | I/O counters and amplification reporting | implemented |
-| Memory budget enforcement | planned |
-| Cancellation at tile boundaries | planned |
+| Memory budget enforcement | implemented |
+| Cancellation at tile boundaries | implemented |
 
 ## Milestone 4 — mesh authoring (in progress, `v0.3.0`)
 
diff --git a/libs/usd-geotiff/tests/test_geotiff_pixel.cpp b/libs/usd-geotiff/tests/test_geotiff_pixel.cpp
index 4d27063..d99fb75 100644
--- a/libs/usd-geotiff/tests/test_geotiff_pixel.cpp
+++ b/libs/usd-geotiff/tests/test_geotiff_pixel.cpp
@@ -399,6 +399,33 @@ int main() {
                      usdgeo::DiagnosticCode::Cancelled, diagnostics);
     options.isCancelled = {};
 
+    diagnostics.Clear();
+    auto midReadBytes = ReadFile(std::string(FIXTURE_DIR) +
+                                 "/geotiff-8x8-uint16-striped.tif");
+    usdraster::MemorySource midReadSource(midReadBytes.data(),
+                                           midReadBytes.size(), "mid-read");
+    usdraster::RecordingSource midReadRecording(midReadSource);
+    usdgeotiff::GeoTiffReader midReadReader(midReadRecording);
+    std::size_t cancellationChecks = 0;
+    options.isCancelled = [&cancellationChecks] {
+      return ++cancellationChecks >= 3;
+    };
+    grid = usdraster::RasterGrid{};
+    Check(!midReadReader.ReadWindow({0, 0, 8, 8}, options, &grid,
+                                    &diagnostics),
+          "mid-read cancellation fails the window");
+    Check(HasCode(diagnostics, usdgeo::DiagnosticCode::Cancelled),
+          "mid-read cancellation has typed diagnostic");
+    Check(grid.IsEmpty(), "mid-read cancellation releases the partial grid");
+    const std::uint64_t midReadPixelOffset = midReadBytes.size() - 128;
+    std::size_t midReadPixelRanges = 0;
+    for (const auto& range : midReadRecording.GetRanges()) {
+        if (range.offset >= midReadPixelOffset) ++midReadPixelRanges;
+    }
+    Check(midReadPixelRanges == 1,
+          "mid-read cancellation stops at a segment boundary");
+    options.isCancelled = {};
+
       diagnostics.Clear();
       CheckIntegerFixture("geotiff-2x2-uint8-striped.tif",
                                     usdraster::RasterDataType::UInt8, 4,