geometry.volume_cylinder

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

Annotations already establish readOnly/idempotent/closed-world, and the description adds real behavioral detail beyond them: π is computed at 50-digit mpmath precision and the result is returned as a 30-significant-digit string. It also discloses the input encoding constraint (Decimal strings, non-negative).

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?

Four tight sentences, front-loaded with the formula, then units, then numeric precision, then the misuse warning. Every sentence conveys information the caller needs; nothing is padding.

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 two-parameter pure function with annotations and an output schema, this covers the semantics, units, input encoding, and output precision an agent needs. Only edge-case behavior (e.g., negative input rejection) is left to inference.

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 load, and it does: radius is identified as the base radius, both values must be non-negative Decimal strings sharing a unit, plus the diameter-vs-radius pitfall. Only upper bounds/precision limits on inputs are unspecified.

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?

Names the exact computation (π * r² * h) and the resource (cylinder volume), so an agent can distinguish it instantly from siblings like geometry.volume_sphere and geometry.volume_cuboid. The formula doubles as a precise specification of what is computed.

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?

Gives clear preconditions for correct use: both inputs must be non-negative Decimal strings in the same length unit, and it explicitly warns that passing a diameter as radius yields a 4x-too-large result. It does not explicitly contrast with sibling volume tools, but the domain makes the choice self-evident.

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