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

Beyond the readOnly/openWorld/destructive annotations, it discloses genuinely useful behavior: missing inputs silently fall back to 'disclosed example defaults', rates are 'baseline allowances', and results should not be recomputed manually. These are exactly the traps an agent would otherwise fall into. It does not mention limits, error behavior, or whether defaults are flagged in the response.

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 short sentences, each front-loading a distinct point (what it does, defaults, rate caveat, guardrail), with no filler. Slightly dense/telegraphic phrasing ('labour inclusion', 'disclosed example defaults') costs a little immediate parseability.

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?

An output schema exists, so return values need no explanation, and the description covers the main behavioral caveats. Given a free-form nested 'values' object with zero schema descriptions, however, the definition should say more about what inputs each calculator expects and what the pricing knobs mean.

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 parameter burden and largely does not. 'Missing inputs use disclosed example defaults' does clarify that the free-form 'values' object can be partially populated, and 'Rates are baseline allowances' touches the pricing object, but calculatorId, the pricing fields (marginMode, vatPercent, marginPercent, contingencyPercent), and what keys 'values' expects remain unexplained.

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 and resource: 'Runs one versioned QuoteBuild formula'. The word 'versioned' and 'one' scope it to a single formula per call, which helps distinguish it from multi-calculator or comparison tools. It does not, however, name a sibling such as prepare_calculation or compare_calculations to complete the differentiation.

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?

'confirm them and labour inclusion before drafting' implies a workflow ordering toward drafting, but the guidance is indirect and phrased as a caution rather than an explicit when-to-use / when-not-to-use rule. It never states which alternative to pick when the agent only wants to preview inputs (e.g., prepare_calculation).

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