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

The description aligns perfectly with annotations (readOnlyHint, destructiveHint, idempotentHint) and adds extra behavioral context: 'charges nothing.' It also details the nature of the data returned without contradicting any annotations.

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?

The description is slightly verbose but front-loaded with the main purpose. Every sentence adds value, detailing what information each combo entry contains. It could be slightly more concise but remains clear.

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 the tool has no parameters and an output schema exists, the description sufficiently covers the tool's purpose, behavior, and return details. It explicitly states it is read-only and free, making it easy for an AI agent to understand when and why to use it.

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 input schema has no parameters, so the description does not need to explain parameter semantics. It effectively describes the output, which is the whole catalog, compensating for the lack of parameters.

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 clearly states the tool 'Returns the full combo catalog' and lists specific attributes included, such as legs, estimated cost, duration, and bug-threshold. It effectively distinguishes from siblings like get_combo_status which retrieves a single combo.

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?

While the description implies it is safe to call anytime by stating 'Read-only; charges nothing,' it does not explicitly mention when to use this tool versus alternatives like get_combo_status. However, the context of being a catalog listing is clear.

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