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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description reinforces it with 'Read-only' and adds real value by disclosing the three data blocks returned. It doesn't describe caching, freshness of prices, or response shape beyond the enumeration, but for a fixed config read that's a minor 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?

Front-loaded with the payoff, then the imperative, then the mode — the ordering is right. The opening sentence is long and list-heavy, and the trailing 'Read-only' duplicates the annotation, but nothing is wasteful enough to cut.

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 carries the whole burden of telling the agent what comes back, and it does so concretely (tiers, prices, seconds at three sizes, nine generation types with limits, credit balance). Combined with a read-only annotation, an agent has everything needed to call it and use the result.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter semantics to explain. The description correctly implies no inputs are needed by framing it as a pure lookup.

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 (get) and resource (generation options), then enumerates exactly what's inside: quality tiers with price-per-call and typical seconds at 16/32/64px, the nine generation types and their limits, and credit balance. That enumeration lets an agent distinguish it from adjacent siblings like quote_generation, generate, or get_account without opening any schema.

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?

'Call it before choosing a tier for the user' gives a clear triggering condition and placement in the workflow. It stops short of naming alternatives or exclusions (e.g. when to prefer quote_generation for a specific quote), so it's strong context without full routing guidance.

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