Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only declare the generic safety profile (readOnly=false, destructive=false, idempotent=false); the description adds genuinely new behavior: the variant is created empty and inactive, no design is generated or copied, and the call consumes the plan's variant limit. That quota side-effect is exactly the kind of context an agent cannot get from structured fields. It stops short of stating permissions or whether creation is reversible.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, zero filler, with the most decision-relevant facts (empty, inactive, no design copy) front-loaded before the quota caveat.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists and annotations cover safety, so the description only needs to convey creation semantics — which it does, including the empty/inactive nature and the plan-limit cost. It omits any pointer to the correct sibling for design-populated variants, a small remaining gap for a create tool with four siblings in the variant family.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 60% and the two documented properties (projectId/generationId alias, setActive) carry rich, well-explained constraints. The description's 'named, inactive' wording loosely maps to label and setActive but adds no syntax, defaults, or requiredness information beyond the schema. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource with meaningful qualifiers: 'Creates an empty, named, inactive content-type variant.' The clause 'Does not generate or copy a design' implicitly separates it from duplicate_variant, but no sibling is named explicitly, so an agent must infer the routing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description never says when to choose this over duplicate_variant or how it relates to list_variants/set_active_variant. The only routing advice ('fill the variant, then call set_active_variant') lives in the setActive schema property, not in the description, leaving the prose with no usage guidance at all.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.