examples: pin mcpp:plugins 0.5.1, and record what shipped

0.5.1 adds the refusal of overlapping roots that the design record states and
0.5.0 shipped without. Every example resolves one version of the package.

Author: speak-agent

.agents/docs/2026-09-08-island-boundary-names.md

@@ -418,7 +418,23 @@ negation.
 | two files in ONE root, one name | refused, and the message says the two belong in two roots |
 | a CPU implementation keeps its place under `backends/` | the additive fixture's three backends land in three namespaces, none of them moved |
 
-## 12. Decided in review
+## 12. What shipped
+
+`mcpp:plugins` **0.5.0** (2026-09-08) carries §2 through §8 and §6.1. **0.5.1**
+carries the refusal of overlapping roots that §6 states and 0.5.0 omitted --
+the shape of defect §10 of the plan warns about, where a requirement folded
+into a larger change disappears when that change ships. It also stops a
+single-file root from registering a re-run glob over the directory that file
+happens to sit in.
+
+Both are indexed, and `mcpp` pins 0.5.1 across the example tree. The published
+0.5.1 was verified in an xlings sandbox against the index rather than a working
+tree: a project written inside the sandbox resolved
+`registry/data/xpkgs/mcpp-x-plugins/0.5.1`, printed `6 12 18 24`, and its
+generated module carried `export namespace sandbox::kernels` and
+`export namespace sandbox::kernels::vec`.
+
+## 13. Decided in review
 
 1. **No compatibility flag** (§9). The four call sites are ours and are updated
    with the release; a flag that kept the global spelling alive would leave the

examples/09-heterogeneous/README.md

@@ -104,7 +104,7 @@ selects it and the accelerator it serves, so a project writes one edge and no
 
 ```toml
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-cuda", "tools-island"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-cuda", "tools-island"], host-module = true }
 ```
 
 `multi-backend/` is the one example here that also pins a version, and it does

examples/09-heterogeneous/boundary/mcpp.toml

@@ -8,7 +8,7 @@ standard = "c++23"
 # `tools-island` is not a device rule: it claims no extension and names no rule
 # module, so the edge states `host-module = true` itself.
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["tools-island"], host-module = true }
+plugins = { version = "0.5.1", features = ["tools-island"], host-module = true }
 
 [build]
 sources = ["src/*.cpp", "src/kernels/**/*.c"]

examples/09-heterogeneous/cann/app/mcpp.toml

@@ -14,7 +14,7 @@ import_std = true
 # imports it as `mcpp.rules.ascendc`. `[build-dependencies]`, because a rule
 # package's library must never reach the target while its rule is wanted.
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-ascendc"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-ascendc"], host-module = true }
 
 # NO [xlings.workspace]. `mcpp.rules.ascendc` declares `xim:cann-toolkit`
 # itself, gated on this accelerator and on the feature that selects the rule --

examples/09-heterogeneous/cuda/README.md

@@ -98,7 +98,7 @@ The rule names it. This project writes one edge and no payload list at all:
 
 ```toml
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-cuda", "tools-island"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-cuda", "tools-island"], host-module = true }
 ```
 
 `mcpp.rules.cuda` declares nvcc, cudart, cuRAND's headers, CCCL and the driver

examples/09-heterogeneous/cuda/app/mcpp.toml

@@ -23,7 +23,7 @@ default = "llvm@22.1.8"
 # `extern "C"` boundary the island's compiler reads and the module the seam
 # imports, so neither signature is stated twice.
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-cuda", "tools-island"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-cuda", "tools-island"], host-module = true }
 
 # The driver's userspace library, reached through an index package that owns
 # the one hop mcpp needs: a directory on the artifact's runtime search path.

examples/09-heterogeneous/hip/app/mcpp.toml

@@ -20,7 +20,7 @@ import_std = true
 default = "llvm@22.1.8"
 
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-hip"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-hip"], host-module = true }
 
 # The driver's userspace library. HIP reaches the device through the CUDA
 # runtime here, so this is the same one hop the CUDA consumer needs: mcpp's

examples/09-heterogeneous/multi-backend/README.md

@@ -93,7 +93,7 @@ saying it after the vocabulary grows.
 
 ```toml
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-cuda", "rules-spirv"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-cuda", "rules-spirv"], host-module = true }
 ```
 
 Two rules, in one build program, which is what an additive-backend package

examples/09-heterogeneous/multi-backend/mcpp.toml

@@ -40,7 +40,7 @@ default = "llvm@22.1.8"
 # The rules are declared unconditionally because `build.mcpp` imports them
 # unconditionally -- each returns immediately when its own backend is absent.
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-cuda", "rules-spirv"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-cuda", "rules-spirv"], host-module = true }
 
 # ── the payloads, gated on the device they are for ──────────────────────────
 #

examples/09-heterogeneous/sycl/app/mcpp.toml

@@ -20,7 +20,7 @@ import_std = true
 default = "llvm@22.1.8"
 
 [build-dependencies.mcpp]
-plugins = { version = "0.5.0", features = ["rules-sycl", "tools-island"], host-module = true }
+plugins = { version = "0.5.1", features = ["rules-sycl", "tools-island"], host-module = true }
 
 # The SYCL runtime, on the artifact's runtime search path. mcpp's private
 # loader does not consult /usr/lib, so `libsycl.so.9` -- which the rule