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

Annotations already declare this a read-only, idempotent, non-destructive, non-open-world operation, so the safety profile is covered. The description adds real value beyond that: newest-first ordering, a per-page cap of both limit lists and 25,000 characters, and the condition under which the cursor is meaningful. It omits permission/auth requirements, which is a minor gap.

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?

Purpose is front-loaded in the first clause, with pagination invariants in a tight second sentence. It is dense but every clause carries information; the phrase 'using the REST contact-list record' is the only slightly loose element.

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 enumerates returned fields (id, name, project, source, row_count, timestamps) and the pagination envelope. Annotations cover safety, but the unexplained project_id filter leaves a small gap for a 4-parameter list 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 only 50% – project_id and limit carry no schema description. The description compensates for limit ('a page holds at most limit lists') and for cursor (via the pagination.next_cursor explanation), but says nothing about what project_id filters or how organization_id scoping behaves, so half the parameters remain underspecified.

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 ... the workspace's contact lists'), and adds scope detail (one bounded, newest-first page) plus the fields returned. This clearly separates it from get_contact_list (single record), create_contact_list (write), and list_contacts (a different resource).

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 clear context for invocation: it lists the workspace's lists, not another workspace's, and explains that next_cursor only continues while has_more is true. It stops short of naming alternatives (get_contact_list, list_contacts) or stating when not to use it, so no explicit exclusion guidance is present.

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