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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the key behavioral traits: the output is a range and not a binding offer, material cost is excluded, a 150 EUR minimum order applies outside Estonia, and there is a 30-calls-per-hour-per-IP rate limit. Those are exactly the caveats an agent needs before quoting a number to a user.

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?

Five short sentences, front-loaded with the core purpose and then the exclusions, pricing caveats, and limit. Every clause carries decision-relevant information; nothing is repeated from the title or schema.

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 six-parameter, nested-object tool with no output schema, the description covers scope, exclusions, currency/VAT basis, minimum order, and rate limits — enough to call it correctly. It stops short of characterizing the returned range structure or explaining the remaining parameters (lang, thickness, material), which keeps it from a 5.

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 only 33%, so the description must carry meaning for the remaining parameters. It adds real value for destination_country (ISO code, example DK, minimum-order consequence) and reinforces the rectangle-only constraint on parts.shape, but says nothing about lang, thickness_mm, material, or the quantity cap, leaving several parameters defined only by bare schema types.

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 opens with a specific verb+resource+scope: a preliminary EUR price range (excl. VAT) for cutting simple rectangular parts from sheet material based on public rates. It immediately bounds the tool ('Rectangles only') and names the sibling for the out-of-scope case ('shaped parts need submit_rfq'), so an agent can distinguish it from submit_rfq without opening either schema.

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?

It states explicitly when to use this tool (simple rectangular cuts, public-rate estimates) and when not to (shaped parts → submit_rfq). It also gives a conditional routing rule for destination_country, noting the 150 EUR minimum applies for shipments outside Estonia, which tells the agent how to call it correctly in that region.

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