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

Annotations already declare read-only, idempotent, non-destructive and closed-world behavior, so the safety profile is covered. The description adds genuine value by disclosing a beyond-schema side-effect boundary ('Does not trigger a provider refresh') and noting the returned refresh timestamps are stored, not live.

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 tightly written sentences with zero waste, and the core action is front-loaded ahead of the non-trigger caveat.

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?

An output schema exists, so return values (watches and timestamps) need not be explained, and annotations cover safety. For a single-param read tool the description is nearly complete, with the only real gap being parameter-level semantics for brandId.

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 0% for the single brandId parameter, so the description must carry the semantic burden and does not: 'this brand's' only loosely implies brandId without stating format, source, or constraints. With low coverage and no compensating detail, this falls below the baseline 3.

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 and resource ('Read ... saved advertiser watches and last refresh timestamps') scoped to a brand, which clearly identifies it as a listing operation. It does not explicitly name siblings like get_ad_watch, so an agent must infer single-vs-list from the plural, keeping it just short of 5.

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?

Usage is implied by the plural 'watches' and the caveat about not triggering a refresh, which helps distinguish it from a refresh/mutation path. However, it never explicitly says when to prefer this over get_ad_watch or create_ad_watch, so guidance is only implied.

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