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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds non-obvious operational context the annotations cannot: zero cost per call, a free quota of 200 per day per IP, and a pointer to published keyed volume pricing. That rate-limit and cost information is genuinely useful before invoking.

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?

One sentence describes the payload, and the pricing metadata is compact and front-loaded with the return semantics. Nothing is repeated from the schema or annotations, and every clause earns its place.

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 burden of explaining return values, and it does: per-plan monthly and annual USD prices, listed features, and AI planning credits. It does not mention plan ordering or whether there is a free tier entry, but it is complete enough for a zero-parameter read tool.

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. The description correctly implies no inputs are needed and instead spends its words on what the response contains.

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?

The description states a concrete verb and resource: it returns plans with their USD monthly and annual prices plus the features shown on the pricing page, including monthly AI planning credits. That is specific enough to know exactly what comes back. It does not differentiate itself from the sibling aieventpro_pricing, which an agent could reasonably confuse with this tool.

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?

Usage is only implied: an agent can infer this is the catalog lookup for plan tiers and prices. There is no explicit statement of when to pick this over aieventpro_pricing or usage_get, and no prerequisites or exclusions are given.

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