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

No annotations are provided, so the description carries the behavioral disclosure burden. It discloses that PATs are preferred and require mcp:products:write or mcp:*, which is useful. However, it does not explain whether updates are partial or full replacements, what happens if a field is not allowed, or what response to expect. The mutation nature is implied by 'Update'.

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 two sentences: the first states the purpose and scope, the second provides crucial authentication context. No wasted words, and the most important information is 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?

The tool has 23 optional parameters, no output schema, and no annotations. The description summarizes the field categories and auth requirements, and the schema handles parameter details. However, it lacks explicit statement of partial-update behavior and return value, which would be valuable for an update operation with this many parameters. The high schema coverage mitigates some of the incompleteness.

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?

The input schema has 100% parameter description coverage, so individual parameter semantics are already well-documented. The description adds high-level categorization (metadata, pricing, listing state, etc.) which helps understanding, but does not add detail beyond the schema. Baseline 3 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?

The description uses the specific verb 'Update' with the resource 'product' and names the categories of fields it can modify (metadata, pricing, listing state, payment options, wallet, branding, slug). This clearly distinguishes it from sibling tools like update_campaign or update_endpoint.

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 clearly implies when to use this tool: when updating product fields. It does not explicitly name alternatives, but the resource-specific scope ('product fields') provides enough context given the sibling tool names. It also adds guidance on authentication (PATs with required scopes).

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