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

With no annotations, the description carries the transparency burden. It discloses one important behavior: 'Missing inputs fall back to their documented defaults.' It also lists what the calculator inputs and output are, implying a pure computation. It does not explicitly state that no data is submitted or persisted, but for a calculator this is a moderate gap, not a severe one.

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 action, but the phrase 'calculator calculator' is redundant and detracts from clarity. The semicolon-separated list is easy to scan, yet the typo and slightly awkward wording keep it from being polished.

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 calculator with four numeric params and no required fields, the description covers the main inputs, the fallback behavior, and the high-level output. However, with no output schema, it leaves the exact return format and units (e.g., currency, breakdown vs total) unspecified. An agent could call it correctly but might be unsure what response to expect.

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 some semantic grouping by naming '409A valuations to budget for' (events), 'Appraisal fees' (price), 'Expedite premium' (rush), and 'Total 409A spend' (output), but it does not clarify the 'years' parameter by name. Overall it provides marginal value beyond the schema.

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 uses a specific verb ('Run') and a specific resource ('the 409A valuation budget calculator'), and it enumerates the calculator's inputs and output. The 'calculator calculator' repetition is a typo but does not obscure the purpose. It does not explicitly distinguish from sibling calculator_describe, but 'run' vs 'describe' is a usable contrast.

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 this tool is used to execute the 409A valuation budget calculation, and the sibling names (calculator_describe, enquiry_describe, submit_enquiry) provide loose context for when to use it. However, there is no explicit when-to-use or when-not-to-use guidance, and no alternatives are named.

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