fix(architecture): remove false CLAUDE_PLUGIN_DATA substitution claim from improve Gotcha

plugins/architecture/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "architecture",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "Scans an existing codebase for module-level architecture friction — shallow modules, seam leaks, and locality gaps — using Ousterhout's deep-module lens, presents candidates as a self-contained HTML report, and runs an interview loop on the selected candidate before handing off for planning.",
   "author": {
     "name": "Melodic Software",

plugins/architecture/CHANGELOG.md

@@ -3,6 +3,18 @@
 All notable changes to the `architecture` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.5.1]
+
+### Fixed
+
+- **The `improve` Gotcha no longer asserts `${CLAUDE_PLUGIN_DATA}` cannot substitute in skill content
+  (#2207).** The plugins reference puts skill and agent content in the "anywhere the placeholder
+  appears" row (<https://code.claude.com/docs/en/plugins-reference>, Environment variables, fetched
+  2026-08-12). The operative rule is unchanged — never store the durable candidate artifact there;
+  even resolved it is plugin-global and collides per-codebase candidates across projects. The 0.3.6
+  changelog entry's wording is preserved per
+  [upstream-drift](../../docs/conventions/upstream-drift/README.md).
+
 ## [0.5.0]
 
 ### Removed

plugins/architecture/skills/improve/SKILL.md

@@ -68,5 +68,5 @@ Graceful degradation — where a named step below is not available in the consum
 
 Observed failure history — patterns that have actually bitten. Add here when a new one surfaces.
 
-- **The durable candidate artifact is a per-project memory-tier file, never `${CLAUDE_PLUGIN_DATA}`.** That token does not substitute in skill markdown content (it is a hook/monitor/MCP path substitution only), and even resolved it points at a plugin-global dir that collides candidates across projects. The artifact resolves through the marketplace topic-docs convention (the plugin's topic-docs [binding](../../reference/topic-docs.md)) — memory tier, default `.work/<topic-slug>/`. A `${CLAUDE_PROJECT_DIR}/.claude/...` path is also wrong: `.claude/` generated output is reserved for observability, and an unignored artifact there leaks scan output into git.
+- **The durable candidate artifact is a per-project memory-tier file, never `${CLAUDE_PLUGIN_DATA}`.** Even resolved it points at a plugin-global dir that collides candidates across projects. The artifact resolves through the marketplace topic-docs convention (the plugin's topic-docs [binding](../../reference/topic-docs.md)) — memory tier, default `.work/<topic-slug>/`. A `${CLAUDE_PROJECT_DIR}/.claude/...` path is also wrong: `.claude/` generated output is reserved for observability, and an unignored artifact there leaks scan output into git.
 - **Scan-agent claims are shipped only after Phase 1.5 reproduction.** Explore agents have a demonstrated error rate: a real run reported a service "registered but never composed — a bug in the seam" that one grep disproved (it *is* consumed, via a different consumer, with tests). Any candidate headed for a `Strong` badge and any runtime-bug / dead-code claim is reproduced against the actual code before it reaches the user-facing report — the report lends every claim its authority, so an unreproduced overstatement is cheap to make and expensive to reputation.