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

With no annotations, the description carries the burden and does disclose side-effect-free behavior ('does not start a purchase or a generation'), the live vs. cached nature of the catalog, and the units of the returned values. It omits any auth requirement or rate-limit context, but for a zero-parameter read lookup the disclosed traits cover the operationally important ground.

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, front-loaded with what is returned, followed by the units and the side-effect disclaimer. 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?

No output schema exists, so the description must characterize the return value, and it does: 'credit packs and model prices' with units ('credits and provider cents'). A brief note on structure or freshness would round it out, but nothing essential is missing for a parameterless lookup.

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 no parameters (schema coverage 100%), so there is nothing for the description to compensate for; baseline 4 applies. The description does not mention parameters, correctly, since there are none.

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 ('Return Studio credit packs and model prices') plus the data source ('live catalog'). It implicitly distinguishes itself from the sibling get_my_credits by clarifying these are catalog prices rather than the user's balance, but it never names that sibling, so an agent must infer the boundary.

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 closing sentence gives an explicit negative boundary — 'This does not start a purchase or a generation' — routing the agent away from start_generation and quote_clipper. It stops short of a positive 'use this when the agent needs pricing before generating', so it is clear context plus one exclusion rather than full when/when-not/alternatives guidance.

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