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

Annotations already cover read-only, idempotent, open-world, and non-destructive behavior, so the description adds strong extra context: exact-fraction output, t bounds, an example result, pricing at $0.001 USDC per successful call, x402/Solana payment, and an HTTPS endpoint.

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 operation, then gives bounds, an example, pricing, and the HTTPS alternative. Every sentence carries useful information, and there is no wasted phrasing.

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 read-only math utility with no output schema, the description covers the operation, output format, parameter bound, payment model, and endpoint. The main remaining gap is the exact structure of the points parameter.

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 helps by defining t as between 0 and 1 and by showing a concrete four-point arch example. It still does not explicitly explain that 'points' must be four coordinate pairs or clarify the string/fraction format expected for t.

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 operation: computing a point on a cubic Bezier at parameter t, returned as an exact fraction. The words 'cubic' and 'point' distinguish it from siblings such as bezier_quadratic, bezier_derivative, bezier_tangent, and bezier_split.

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?

Usage is implied by 'cubic Bezier' and 'Point on', which naturally routes an agent away from quadratic, derivative, tangent, and split siblings. However, there is no explicit when-to-use statement, no exclusions, and no named alternative.

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