Conciseness

The body is dense with non-obvious, high-value rules (exact import table, "use node" placement, storage-id discipline) with no explanation of concepts Claude already knows, matching the efficient anchor. It falls short of lean/5 because the opening paragraph restates the frontmatter description nearly verbatim ("Knows the object-form function syntax, validator requirements, index naming rules...") and the SELF-VERIFY RULE bullet is a run-on sentence that could be tightened.

Actionability

Mostly executable: exact imports ("`query`/`mutation`/`action`... come from `./_generated/server`") and copy-paste commands ("npx tsc --noEmit", "npx convex dev --once", "CONVEX_AGENT_MODE=anonymous npx convex dev --once") appear with concrete API names. The gap keeping it at 4 rather than 5: the headline pattern — object-form functions with args and returns validators — is mandated repeatedly ("Object form only", "args and returns validators on every registered function, no exceptions") but never shown with a short example, leaving the most common case demonstrated only in prose.

Workflow Clarity

The 6-step Workflow is clearly sequenced (read schema first → write → verify push) and closes with an explicit validation checkpoint, while the SELF-VERIFY RULE adds the full feedback loop: run "npx tsc --noEmit" and push, "Fix every error it reports before finishing", with conditional branching on whether "npx convex whoami" succeeds. This matches the anchor with explicit validation steps and error-recovery loops.

Progressive Disclosure

The skill is a single well-organized file under 50 lines with no bundle files (no references/, scripts/, or assets/), and its two sections (Workflow, Rules) are clearly signaled — per the simple-skill guideline this could reach 5. It sits at 4 because the Rules list opens with a dangling pseudo-header bullet ("DATA ACCESS + IMPORTS — read before writing any convex/*.ts (front-loaded, not a post-hoc lint):" followed by flat siblings), a minor organization gap suggesting an intended subsection that was flattened.

Specificity

The description enumerates concrete coverage areas — "function definitions, schemas, indexes, queries, mutations, actions, HTTP endpoints, cron jobs, file storage, auth wiring, and component installation" — plus specific knowledge items ("object-form function syntax, validator patterns, resource limits"). This matches the anchor 'lists multiple specific concrete actions; comprehensive coverage'; there is no vagueness or buzzword padding to drop it below 5.

Completeness

It explicitly answers both questions: what ("Convex backend specialist. ... Knows the object-form function syntax, validator patterns, resource limits, and component ecosystem") and when ("Use this agent for any code inside a `convex/` directory"). This is the anchor-5 pattern of a clear what plus a concrete explicit trigger phrase, not merely implied timing.

Trigger Term Quality

It covers the natural vocabulary a Convex developer actually uses: "convex/" directory, "Convex backend", "queries, mutations, actions", "schemas, indexes", "cron jobs", "file storage, auth wiring". These are the exact terms and file-path triggers a user would say when needing this skill, matching the comprehensive-coverage anchor; nothing common is missing.

Distinctiveness Conflict Risk

The niche is unambiguous — Convex-specific artifacts ("convex/ directory", "@convex-dev"-style components, "convex dev" workflows) with a directory-scoped trigger. No other skill category would plausibly claim these triggers, so conflict risk is minimal, matching the clear-niche anchor.