List buyable credit packages

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

With no annotations provided, the description carries the full burden. It accurately states the operation is a list and specifies the output fields, but doesn't disclose authentication requirements, rate limits, or whether the list is complete/unpaginated. The verb 'List' implies read-only, but this is not explicit.

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 concise sentences: the first states the purpose and lists return fields, the second gives a direct usage directive. No wasted words or redundant elaboration.

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?

Given no output schema and no parameters, the description adequately explains what is returned and how to use it. It doesn't mention pagination, ordering, or authentication requirements, but for a presumably small list of credit packages, these are minor omissions.

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 has zero parameters, so schema coverage is trivially 100%. The description adds no parameter-specific semantics, but with no parameters to document, the baseline of 4 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?

The description uses a specific verb 'List' with a specific resource 'credit packages', and enumerates the exact fields returned (id, name, credit amount, price in USD, price per 1k credits). This clearly distinguishes it from siblings like buy_credits (purchase) and get_credits (likely balance).

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 explicitly directs the agent to use the returned package id with buy_credits, providing a clear next step and implicit alternative. It doesn't state when not to use or mention sibling tools like get_credits, but the context is sufficient for typical use.

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