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

Annotations already mark readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable behavioral context by explaining the structure of the delivery_terms field (enum values, null handling, empty-list meaning) – information not present in annotations or schema. This goes beyond the baseline, though it doesn't address rate limits or error behavior.

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 a single paragraph that leads with the main purpose and available fields, then details the delivery_terms structure. While somewhat long, each clause earns its place – the delivery_terms explanation is essential for correct usage. It could be tightened slightly, but it's well organized and front-loaded.

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?

Given the tool is a simple read operation with annotations covering safety and full schema coverage, the description is largely complete. It explains the nuanced delivery_terms format and usage trigger. However, it doesn't mention potential edge cases (e.g., product not found) or the full return shape, which would be useful. Still, it's sufficient for correct invocation.

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%: both 'slug' and 'locale' have descriptive text. The tool description does mention 'requested language' which maps to locale, but it doesn't add any syntax or format details beyond the schema. This meets the baseline but does not elevate it.

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 states a specific verb ('Fetch'), a clear resource ('one product'), and enumerates the exact data fields returned (MOQ, lead time, Incoterms, HS code, etc.). It implicitly distinguishes from siblings like search_products (search vs. fetch) and get_manufacturer (supplier only vs. full terms).

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 final sentence explicitly instructs when to use the tool: 'Use it once the person has picked a product from search_products and wants the terms.' This gives a clear trigger and preconditions, routing the agent appropriately without needing to guess.

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