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

With no annotations provided, the description carries full burden. It discloses the outputs (Kv, Cv, x, Y, choked-flow check) and the calculation methodology (mass-flow form, IEC standard), adding meaningful behavioral context. It does not detail limitations or interpretation of the choking check, but overall is transparent for a calculation tool.

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 concise and front-loaded, with three sentences covering purpose, outputs, and a source credit. The 'Powered by multicalci.com' sentence provides little value for an AI agent, slightly reducing conciseness, but the overall structure is efficient.

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 an 8-parameter tool with no output schema, the description adequately states the return values and the calculation standard. It does not elaborate on edge cases (e.g., choked flow behavior) or interpret the results, but the description is sufficiently complete for invoking the tool correctly.

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 is 3. The description adds no parameter-specific details beyond the schema; it mentions the mass-flow form and outputs but does not elaborate on parameter meanings or relationships, so the schema already carries the weight.

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 states 'Size a control valve for gas or vapour service per IEC 60534-2-1' – a specific verb ('size') with a well-defined resource and scope. It distinguishes from the sibling 'control_valve_size_liquid' by explicitly naming gas/vapour service and specifies the calculation form.

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 provides clear context for gas/vapour service and references the relevant IEC standard, implying when to use it. However, it does not explicitly mention the alternative 'control_valve_size_liquid' or provide explicit exclusion conditions, so it falls short of a full 5.

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