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

Annotations already establish that the tool is read-only, idempotent, non-destructive, and open-world. The description adds important behavioral context beyond that: the cost is $0.001 USDC per successful call via x402 on Solana, and the same tool is available over HTTPS.

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 front-loaded with the core definition and formula, followed by useful examples, bounds, price, and endpoint. Every sentence contributes information; there is no filler or redundant restatement.

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?

For a simple pure math tool with annotations covering safety and no output schema, the description is nearly complete: it gives the formula, examples, input bounds, and payment details. It could be slightly more explicit that the result is returned as an integer count, but the first sentence implies this clearly.

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?

Schema description coverage is 0%, so the description must carry the parameter meaning. It defines n as the number of types and k as the number of elements chosen, provides the formula, and states that both range from 0 to 1024, which compensates well for the empty schema descriptions.

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 names a specific mathematical operation: the number of ways to choose k elements from n types with repetition, and gives the exact formula C(n+k-1, k). This distinguishes it from ordinary binomial-style siblings such as binom, since repetition is explicitly stated.

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 definition and examples make clear when the tool applies: computing multiset combinations with repetition. However, it does not explicitly compare itself to nearby alternatives such as binom or stars_bars, so the agent must infer the boundary rather than being routed directly.

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