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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds useful behavioral context beyond annotations: pricing per successful call, the HTTPS endpoint, valid input range, and sample output values. It does not contradict any annotation.

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 examples, then moves to range and commercial details. All sentences carry useful information, though the repeated sample values make it slightly dense.

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?

There is no output schema, so the description should convey return values; the sample sums do this well. Annotations cover safety and idempotency, and the description supplies range, pricing, and endpoint details. The only missing piece is a definition of Moran numbers, which may matter to some callers.

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 sole parameter n has 0% schema description coverage, so the description must carry the burden. It explains that n is the upper bound, states the range 1 to 2000, and provides concrete sample inputs and resulting sums. It could go further by defining Moran numbers, but it adds substantial parameter meaning.

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 a specific verb and resource: it returns the sum of Moran numbers up to n. The examples and range make the operation unambiguous, but it does not explicitly distinguish itself from sibling tools such as moran_count or moran_next.

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 implies when to use the tool by defining it as a sum over Moran numbers at most n, and it states the valid range 1 to 2000. However, it gives no explicit guidance on when to choose this tool over the related moran, moran_count, moran_next, or moran_ratio tools.

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