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

Annotations already declare readOnlyHint/destructiveHint, but the description adds real context: not_found behavior for missing/inaccessible IDs, the semantic scope of knownBrands (brand names/websites, not Site records), and explicit confirmation of no provider research or Scan. The 'no mutation' clause is somewhat redundant with the annotations, but the error behavior and data-shape notes go beyond structured fields.

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 core action and resource, then layers return shape, error behavior, and usage guidance in a compact block. Dense but nearly every sentence carries distinct information; minor redundancy on the no-mutation clause.

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 an output schema present, return-value detail is not needed, and the description covers the remaining essentials: error behavior, sibling routing, and the pre/post-write usage pattern. Nothing an agent needs to call it correctly is missing.

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 0% for the single clientId parameter, so the description carries the burden. It adds meaningful context by indicating the ID originates from list_clients, but gives no format or validation detail (UUID). Adequate but not fully compensating for the coverage gap.

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?

States a specific verb (Read) and resource (one accessible Client by clientId), and explicitly situates it against list_clients (the source of the ID) and get_site/get_topic style alternatives via list_sites_and_topics. An agent can distinguish it from the many other get_* siblings without opening any 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 workflow triggers ('Read before editing and after an uncertain write') and names the alternative tool (list_sites_and_topics) with the condition that selects it. This is textbook when-to-use guidance.

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