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

Annotations already declare destructiveHint=true, so the write nature is covered; the description still earns credit for disclosing the upsert semantics (existing product is updated rather than rejected) and the downstream consequence on future tax calculations. It stops short of saying which fields an upsert overwrites on an existing product.

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?

Two short, front-loaded statements with the verb first and the blast radius second; caps emphasize the write. The trailing 'Numeral: POST /tax/products' endpoint reference adds little for an agent selecting the tool, keeping it just short of ideal.

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 3-parameter mutation with no output schema and minimal annotations, the description supplies the transferable facts an agent needs: it writes to the catalog, it upserts, and it affects downstream tax results. Missing only auth/permission prerequisites and what happens to fields omitted on upsert.

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 coverage is 100%, so all three parameters are already documented in-schema with examples for the category taxonomy. The description only restates the tax category parameter and adds no format or constraint detail, so the schema does the heavy lifting and a 3 baseline is appropriate.

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 ('CREATES (or upserts) a product with its tax category') plus the concrete effect on the catalog that drives tax calculations. The upsert framing distinguishes it from the read siblings numeral_get_product and numeral_list_products without needing to name them.

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 impact statement ('drives future tax calculations') implies the tool should be used to register products before calculations, but there is no explicit when-to-use rule, no exclusion ('use get_product to look up an existing id first'), and no alternatives named. Usage is inferable rather than stated.

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