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

With no annotations, the description carries the full burden and does disclose the pagination contract ('up to 250 per page; pass next_page to continue') and the shape of returned data including approval status and issue remediation text. It stops short of stating permissions/read-only nature or error behavior, but the operational traits an agent needs are largely present.

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?

Front-loaded with the resource and returned fields, then the filtering flag, then paging, then sibling routing. Every sentence carries distinct information with no 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?

With no output schema, the description must describe return content and does so concretely (offer id, title, price, availability, link, approval state, issues and fixes). Paging, filtering and sibling boundaries are all covered, leaving nothing essential unspecified.

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 the baseline is 3, but the description adds real meaning by restating what issues_only does ('keeps the ones with a problem') and by tying next_page to the paging limit. That goes beyond the schema's terse per-parameter text.

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?

Names the specific resource (products in a Merchant Center account) and verb (list, with enumerated returned fields). It explicitly distinguishes its scope from merchant_status (counts) and merchant_report (clicks/impressions), so an agent can route without opening a 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?

Gives explicit when-to-use-this-instead routing for two siblings with their conditions ('for counts across the whole catalogue use merchant_status; for clicks and impressions merchant_report'). It does not address the singular merchant_product sibling, which leaves one plausible alternative un-distinguished.

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