diff --git a/plugins/toolchain/.claude-plugin/plugin.json b/plugins/toolchain/.claude-plugin/plugin.json
index ad2f5deae..47f4636b2 100644
--- a/plugins/toolchain/.claude-plugin/plugin.json
+++ b/plugins/toolchain/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "toolchain",
-  "version": "0.4.2",
+  "version": "0.4.3",
   "description": "Repo-agnostic polyglot verification toolchain: build + test + lint for changed files across .NET, Python, TypeScript, Bash, PowerShell, Markdown, YAML, and cross-cutting surfaces (`/toolchain:check`, `/toolchain:lint`), plus a re-runnable `/toolchain:setup` with check (report the configured ecosystems and their command surface) and apply (interview, infer, and write the tracked per-ecosystem command config those skills resolve first).",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/toolchain/CHANGELOG.md b/plugins/toolchain/CHANGELOG.md
index 465a85a1e..b62d4cf94 100644
--- a/plugins/toolchain/CHANGELOG.md
+++ b/plugins/toolchain/CHANGELOG.md
@@ -3,6 +3,21 @@
 All notable changes to the `toolchain` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.4.3]
+
+### Changed
+
+- **Presence-gated `dotnet-msbuild:*` build-diagnostics references in `context/dotnet.md` reframed as
+  .NET-ecosystem forward references.** The `## Marketplace plugin skills for build diagnostics (invoke
+  only when installed)` list gains a lead-in that frames its `dotnet-msbuild:*` skills as applicable
+  when your stack is .NET and as forward references to the planned `dotnet-*` plugin family — invoked
+  only when the plugin is installed, otherwise falling back to the section's own prose remediation and
+  binlog gotcha (the generic path stays first-class). Framing only: no skill reference was removed,
+  renamed, or genericized, and no command string was altered. Aligns this file with the presence-gated
+  forward-reference convention the merged `testing` (#491) and `verification` (#526) siblings adopted,
+  per the ratified #412 disposition. Addresses #412; the sibling `implementation` finding (#405) tracks
+  the same pattern separately.
+
 ## [0.4.2]
 
 ### Fixed
diff --git a/plugins/toolchain/skills/check/context/dotnet.md b/plugins/toolchain/skills/check/context/dotnet.md
index 0d19aa34c..7fdc85af0 100644
--- a/plugins/toolchain/skills/check/context/dotnet.md
+++ b/plugins/toolchain/skills/check/context/dotnet.md
@@ -71,6 +71,8 @@ Checks repos often gate in CI that plain build/test/format don't catch locally 
 
 ## Marketplace plugin skills for build diagnostics (invoke only when installed)
 
+These are .NET-ecosystem plugin skills — applicable when your stack is .NET — and forward references to the planned `dotnet-*` plugin family: invoke each only when its plugin is installed, otherwise fall back to the prose remediation and the binlog gotcha above.
+
 - **Slow builds** — `dotnet-msbuild:build-perf-diagnostics` for bottleneck analysis via binary logs, `dotnet-msbuild:build-perf-baseline` for before/after measurement
 - **Build failures** — `dotnet-msbuild:binlog-failure-analysis` to diagnose opaque MSBuild errors, `dotnet-msbuild:binlog-generation` for binary log capture (`dotnet build /bl:{}`)
 - **Build config issues** — `dotnet-msbuild:msbuild-antipatterns` for AP-01 through AP-21, `dotnet-msbuild:check-bin-obj-clash` for OutputPath conflicts