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

Annotations already declare read-only, idempotent, non-destructive behavior, and the description adds meaningful operational context: cost per successful call, payment scheme (x402, Solana), and an HTTPS endpoint. It does not fully explain payment mechanics or error/retry behavior, but it adds substantial value beyond the 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 short and front-loads the core definition and index semantics before adding pricing and transport details. The example is useful, though slightly cryptic, and the pricing/endpoint sentences are relevant but secondary.

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 two-parameter math tool with no output schema, the description covers the main concept and gives an example result, but it leaves the terms parameter and exact return shape under-specified. It is adequate but not fully complete for an agent relying on the description over the schema.

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?

With 0% schema description coverage, the description must compensate. It explains the index parameter well, including zero-based indexing and the last-index behavior, but it does not explicitly define the terms array as the continued-fraction coefficients, leaving one of two required parameters partially inferred.

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 identifies the resource as one convergent of a continued fraction and explains the index convention with a concrete example. It does not explicitly differentiate the tool from siblings such as cf_expand, cf_value, or cf_best, so it stops short of full sibling-level clarity.

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 that the tool is used to retrieve a convergent from a continued fraction, but it gives no explicit when-to-use guidance, prerequisites, or comparison to alternatives like cf_expand or cf_value. The example clarifies output semantics rather than usage conditions.

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