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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is fully covered. The description adds the returned units (Pa, kPa, bar, psi), but that is also captured by the output schema, so net new behavioral context is modest.

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?

Compact and front-loaded: formula, usage, inputs, outputs, cross-reference, in one tight block. The list_bundles sentence is slightly tangential but cheap and does not bury the core facts.

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?

With an output schema present, the return values needn't be explained, and the description correctly covers the formula and both operands. The unit mismatch between description (m²) and schema (cm²) is a real completeness defect for a two-parameter physics tool where units decide correctness.

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 100% so the baseline would be 3, but the description actively contradicts the schema: it says 'area m²' while the parameter is area_cm2 documented as 'Piston area cm²'. An agent following the description could supply a square-metre value into a square-centimetre field and get a result off by 10,000x. This is misleading rather than additive.

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?

States a specific verb+resource ('Compute hydraulic system pressure') and even gives the governing formula P=F/A, which distinguishes it from generic siblings like calculate_pressure_convert and calculate_water_pressure_loss. However, it does not explicitly name which sibling to prefer, so an agent still has to infer the boundary against calculate_force and the pressure converters.

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?

'Use for hydraulic design' gives a domain context but no when-not-to-use or explicit alternative. The pointer to list_bundles for related 'science' calculators is a soft routing hint rather than a selection rule, and it never says that unit conversion should go to calculate_pressure_convert.

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