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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description still adds real behavior: results come back in request order, one refusal does not abort the other runs, and no pricing data is returned. The 'No prices' exclusion is a genuinely useful disclosure that is not encoded in any structured field.

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 purpose and scope are front-loaded in the opening clause, and the trailing 'No prices.' earns its place as a constraint. It is a single long semicolon-chained sentence, which is dense but wastes no words.

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 and full schema coverage, the description need not explain return values, and it correctly focuses on the non-obvious parts: ordering, partial-failure semantics, and the absence of prices. It omits any mention of the `detail: summary` token-saving mode, which is the one usage-relevant gap.

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 schema already documents every parameter, including slug-or-permanent-id, the inputUnits escape hatch, and market/system overrides. The description restates slug/inputs at a high level and adds nothing about the top-level `detail` parameter (full vs summary) or override precedence, so the baseline 3 applies.

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 (runs), resource (construction calculator calculations) and a hard scope (up to 25 in one request), which lets an agent separate it from the single-shot `calculate` sibling without opening either schema. It stops short of naming that sibling explicitly, so the differentiation is inferential rather than stated.

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 batching language ('several calculators in one request', 'up to 25') implies when this tool is appropriate versus `calculate`, but there is no explicit when-to-use or when-not-to-use statement and no alternative named. Usage must be inferred from the capability description.

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