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

Annotations already cover readOnly/non-destructive/closed-world, and the description adds value beyond them: it declares the return shape (listId and name) and, importantly, disambiguates an empty array as either no match or no connected integration. Scope/authorship of IDs ('belong to this account') is also disclosed.

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?

Three short sentences, front-loaded with the action, then return shape, then the edge case and follow-on tool. No filler or repetition.

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 correctly carries the return-value burden (lists with listId and name) and covers the empty-result and integration-missing cases. Matching behavior is left entirely to the schema's 'free-text' wording, a minor gap for a single-parameter search tool.

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?

With a single parameter and 100% schema description coverage, the schema already defines 'name' as a free-text filter. The description restates 'by name' but adds no matching semantics (substring vs. exact, case sensitivity), so it holds at the baseline.

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 and resource ('Search destination lists ... by name') scoped to the connected marketing-automation integration, which clearly separates it from generic list tools. It does not explicitly name the sibling it contrasts with (list_marketing_automation_lists), so differentiation is implied by 'by name' rather than stated.

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?

Explains the empty-array case ('no matching list or no connected integration') and names the downstream tool that consumes the result (set_default_ma_list), giving the agent clear context for using the output. It stops short of explicitly saying when to prefer this over enumerating via list_marketing_automation_lists.

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