Conciseness

The ~130-line body carries only non-obvious, decision-critical information ("Sandboxed runtime code can use Web APIs but not Node.js built-ins", "Patch does not imply read", the 8 MiB body bound) and assumes Claude's competence with no padding about general concepts. The only redundancy — five references linked both inline and again in the References list — is navigation rather than over-explanation, so it stays at anchor 5 rather than 4.

Actionability

Provides copy-paste-ready scaffold commands ("pnpm dlx @emdash-cms/plugin-cli init my-plugin") and a complete, typed `src/plugin.ts` example, plus exact identifiers throughout ("createPluginTestHost()", "host.http.respond()", "ctx.storage.<collection>", import paths "emdash/plugin"). These fully cover the common cases; the one omission (no inline `emdash-plugin.jsonc` manifest snippet) is a shape the CLI generates, so it does not fall to anchor 4's "minor gaps".

Workflow Clarity

Sections follow the natural build order — Choose a format → Scaffold → Declare access → Routes/Hooks/Admin UI → Runner parity → Test the production boundary — with real validation checkpoints (the two test-host tiers, "Dispose every host after use", `pnpm run test` in the scaffold). It is anchor 4 rather than 5 because the sequence is implied by section order rather than explicit numbered steps, and there is no fix-and-retry feedback loop or checklist; it stays above anchor 3 because validation is concrete and present, not missing.

Progressive Disclosure

The overview holds decisions while ~2,300 lines of per-API detail are split across 12 real reference files, each well-signaled inline from the section that needs it ("Read [API routes and MCP tools](./references/api-routes.md)") and in a consolidated list. References are one level deep with only sibling-level cross-links (e.g., admin-ui.md → block-kit.md), matching anchor 5; the inline 28-row capability table is summary-level decision content, not misplaced detail.

Specificity

Enumerates concrete capabilities — "sandboxed hooks, routes, storage, content and media APIs, MCP tools, and declarative admin UI, or native React and Astro extensions" — with no vague filler, matching the anchor for multiple specific concrete actions with comprehensive coverage of the plugin domain. It is not anchor 4, which requires minor gaps in coverage; none are visible.

Completeness

Explicitly answers both "what" ("Create EmDash CMS plugins with sandboxed hooks, routes, ... MCP tools, and declarative admin UI, or native React and Astro extensions") and "when" ("Use when scaffolding or implementing an EmDash plugin") with concrete trigger phrases — the anchor-5 pattern. It is not anchor 4 because the "when" clause is explicit and specific rather than improvable.

Trigger Term Quality

"Use when scaffolding or implementing an EmDash plugin" plus natural terms users would actually say ("MCP tools", "React and Astro extensions", "admin UI", "hooks", "routes") give comprehensive coverage for this niche, including both action verbs and both plugin formats. No natural term is missing in a way that would fit anchor 4's "a few natural terms missing".

Distinctiveness Conflict Risk

"EmDash CMS" names a clear niche with distinct triggers ("scaffolding or implementing an EmDash plugin"), so no other skill would plausibly fire for this request. Minimal conflict risk matches anchor 5; anchor 4 would require overlap with closely related skills, which the product-specific naming precludes.