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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered; the description adds genuinely new behavior: the call is free, nothing is rendered, and the response carries a render price (credits plus refine_credits). It does not mention that repeated calls produce different directions even though idempotentHint=false, which is the remaining gap.

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?

Three tight sentences: purpose, cost/scope caveat, then return shape and next step. The most decision-relevant fact (free, nothing drawn) is front-loaded and no sentence is filler.

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?

With no output schema, the description still names the returned fields (label, prompt, credits, refine_credits) and closes the loop with the create_logo hand-off, so an agent knows both what comes back and what to do next.

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 description coverage is 100%, so brand_id, request, logo_type and count are all documented in the schema; the description adds nothing beyond that about parameter formats or limits (e.g. the max of 10 directions, the default of 4). Baseline 3 applies when the schema does the heavy lifting.

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 ('write distinct logo directions for a brand from a brief') and immediately delimits scope with 'Free; nothing is drawn', which separates it from the rendering sibling create_logo. The difference from create_logo is made unambiguous by the follow-up instruction to call it only after the user picks a direction.

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?

Provides an explicit end-to-end flow: show the directions, ask which one to render, then call create_logo with that direction and its price. That is a when-to-use statement plus the named alternative and the condition selecting it.

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