List Contact Lists

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered structurally. The description still adds real value beyond that by disclosing what the response carries (contact counts) and a presentation constraint (don't surface ids/timestamps unless asked), though it says nothing about pagination behavior for a paginated endpoint.

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 with zero filler; the core purpose is front-loaded and each following sentence adds a distinct piece of information (domain meaning, output-presentation rule). Nothing is redundant with the schema or annotations.

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 usefully names what comes back (lists with contact counts) and how to present it. Pagination semantics are fully covered by the schema's cursor descriptions, so the remaining gap — return shape details such as fields beyond counts — is minor for a read-only listing 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?

Schema description coverage is 100%, so after/before/limit/search are fully documented in the schema, including the mutual exclusion of after and before and the 1-100 limit. The description adds no parameter information, so the baseline 3 is correct when the schema does all the work.

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 (list contact lists) and immediately adds scope detail that competitors lack: the results include contact counts and represent static audiences that campaigns target. This reads clearly against siblings like get-list (single item), create-list, and update-list.

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?

There is no explicit when-to-use guidance and no routing to alternatives (e.g., search by name vs. paginate through all lists). The domain note that lists are static audiences is context, not a usage rule, and the id/timestamp instruction is about output presentation rather than tool selection.

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