List / segment contacts

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely useful behavior context — pagination with a 100-item cap and ISO 8601 date formats — but says nothing about auth requirements, rate limits, or how the cursor is used across calls.

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?

Two tight sentences with zero filler; the core operation and its filter dimensions are front-loaded, and pagination follows immediately. Every clause carries information.

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?

For a 9-parameter read tool with no output schema and low schema coverage, the description is adequate but not complete: it never indicates the shape of the response (contacts plus paging cursors), which matters because there is no output schema to fall back on.

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 only 44% across 9 parameters, so the description must compensate. It does add the ISO 8601 format for the four date-range params (the schema leaves them bare) and the 1-100 page-size bound, but it is silent on the required listId, the starting_after cursor, and the status enum values.

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 (List) and resource (contacts) scoped to a list, and enumerates the filter dimensions (tag, status, date ranges). It is easily distinguished from single-contact siblings like get_contact, though it never names an alternative explicitly.

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?

Usage is implied by the phrasing 'List contacts in a list, filtered by...' but there is no explicit when-to-use guidance, no statement of when to prefer get_contact/upsert_contact, and no preconditions. An agent can infer the intent but gets no routing help.

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