list_contacts

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

Annotations already declare readOnlyHint=true, which is consistent. The description adds that it returns one cursor-paginated page, providing useful behavioral context beyond the annotation. No contradictions, and the pagination detail helps an agent understand iteration.

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?

The description is a single sentence that is concise, front-loaded with the action, and contains no unnecessary words. It efficiently communicates the tool's purpose.

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 does not explain the return format (e.g., array of contacts, nextSkipToken). While the pagination intent is clear, the lack of output details makes it minimally adequate for a tool with 5 parameters. A brief note on the result shape would improve completeness.

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 the description does not need to add parameter details. It does not elaborate on parameters, which is acceptable since the schema already documents them clearly. Baseline score of 3 is appropriate.

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 clearly states 'List one cursor-paginated page of contacts in an XM Directory mailing list', specifying the verb (list), resource (contacts), and scope (one page, specific mailing list). This distinguishes it from siblings like get_contact (single contact) or list_mailing_lists.

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?

The description implies usage for listing contacts paginated, but does not explicitly state when to use this tool versus alternatives like get_contact for single contacts or bulk_import_contacts for bulk operations. No 'when not to use' guidance is provided.

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