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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true, so the agent knows this is a safe, non-destructive write. The description adds valuable context that only provided fields are changed, which is a critical behavioral trait beyond the annotations. No contradiction with annotations.

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 exceptionally concise: two short sentences that state the operation and the key partial-update behavior. Every word earns its place, with no redundancy or filler.

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 has 9 parameters with 100% schema coverage, an output schema, and annotations covering safety properties, the description is complete enough for typical usage. It clearly communicates the core action and partial-update behavior. It does not need to repeat schema details, though it could mention edge cases like product-not-found, but that is not critical given the required productId parameter.

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%, and each parameter has a clear description in the schema. The description in the tool description adds no parameter-specific information beyond the general partial-update behavior, which applies to all parameters. Baseline 3 is appropriate since the schema carries the semantic burden.

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 clearly states a specific verb ('Update') and resource ('existing product'), and distinguishes from siblings like create_product and get_product. The additional phrase 'Only provided fields are changed' clarifies the partial-update semantics, making the purpose unambiguous.

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 description implies when to use this tool: to modify an existing product, not to create one. While it does not explicitly name alternatives like create_product, the context is clear enough for correct selection. No exclusions are stated, but the update vs create distinction is evident from the name and description.

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