Conciseness

The body is directive-dense with no concept explanations Claude already knows (e.g., 'Renderer swap first, streaming optimization second'). However, bullets like the Vue 3 fade/streaming policy ('they can be enabled together... Do not carry a legacy :fade="!isStreaming" binding...') are multi-clause and partially overlap, so minor trimming is possible. This is the 4 anchor (efficient, minor instances that could be trimmed) rather than 5 (every token earns its place).

Actionability

Concrete, executable guidance throughout: named props and options (mode="chat", smooth-streaming="auto", codeBlockOptions, stream-diffs, parseOptions.preTransformTokens, htmlPolicy / html-policy="trusted"), concrete audit search terms, and unambiguous decision rules. As an instruction-only skill, absent code is not penalized, but there are minor gaps such as no example install command and no sample scoped override mapping. Solidly 4, not 5.

Workflow Clarity

Both routes are clearly numbered and sequenced, with an explicit routing decision up front and validation steps ('Run the smallest relevant tests or build', 'Validate the migrated behavior and leave a rollback path'). Feedback loops (fix and re-validate) are implied rather than explicit, which fits 4 (clear sequence, most checkpoints, minor validation gaps) rather than 5.

Progressive Disclosure

Good structure: an overview with two clearly signaled, real, one-level-deep reference links (verified present in references/ with no nested references) plus a Default Decisions section. Minor gaps: the dense mode/fade/streaming decision guidance in Route A step 6 reads like reference material inlined in the overview, and the 'Useful Doc Targets' are bare repo paths rather than signaled links to the bundle. Fits 4 rather than 5.

Specificity

The description lists multiple concrete actions (audit and migrate Markdown rendering, upgrade markstream-vue 1.x to 2.x, migrate custom renderers into scoped overrides, replace removed 1.x code-block dependencies, APIs, preview payloads, and parser types) with comprehensive coverage and no vague filler. Third person is used throughout, and 4 would require minor coverage gaps that are not present.

Completeness

It explicitly answers both what ('Audit and migrate existing Markdown rendering to Markstream, or upgrade a markstream-vue 1.x integration to 2.x') and when ('Use when Codex needs to replace another renderer, classify direct vs custom vs plugin-heavy adoption...'). The when-clause is fully explicit with concrete trigger phrases, matching the 5 anchor; 4 would require a less explicit when.

Trigger Term Quality

Good natural keyword coverage ('Markdown rendering', 'renderer', 'markstream-vue', '1.x integration to 2.x', 'custom renderers', 'streaming'), but common renderer names users would naturally say (react-markdown, markdown-it, marked) appear only in the body, not the description. This fits the 4 anchor (good coverage, a few natural terms missing) rather than 5's comprehensive synonym coverage.

Distinctiveness Conflict Risk

It occupies a clear niche (Markstream / markstream-vue migration) with product-specific trigger terms unlikely to appear in other skills. Minimal conflict risk, matching the 5 anchor.