calculate_combinations

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

With no annotations, the description carries the transparency burden. It discloses a cost of $0.001 USDC via x402, which is a useful behavioral trait. However, it does not state that the operation is read-only, does not modify data, or what the return behavior is. The cost disclosure is the only behavioral information.

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 extremely short, but this is under-specification rather than conciseness. It front-loads the tool name and then adds cost information, but omits essential details about usage or parameters. The structure is not helpful for an agent; it reads as a label rather than a functional guide.

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?

This tool is completely inadequate for invocation. There is no output schema, no real parameter definitions, and the description gives no clue about expected inputs or return format. For a calculator, the agent needs to know what numbers to supply; this description provides none of that. The cost note is irrelevant to operation.

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 a single 'params' object that is described only as 'Tool parameters as JSON object', providing zero information about actual required fields. Although schema coverage is literally 100%, the description is generic and the tool description adds no parameter meaning. An agent cannot infer what values to pass (e.g., n and r for combinations).

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 'calculate combinations' which is a verb+resource, but it merely repeats the tool name without elaboration. It gives no detail on what kind of combinations (e.g., n choose k, permutations vs. combinations) or what input is expected. The phrase 'Other Utilities tool' places it in a category but does not distinguish it from sibling utilities.

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?

There is no guidance on when to use this tool or how it differs from other calculators. No mention of prerequisites, alternative tools, or exclusions. The description provides no context for an agent to decide between this and sibling math tools like factorial_calculator or prime_operations.

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