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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds the default ordering and paging behavior, but says nothing about result shape, size limits, or pagination bounds beyond the schema defaults.

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 tight sentences, purpose front-loaded, and every clause earns its place by enumerating a distinct filtering axis. No filler or restated title.

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 10-parameter tool with no output schema, the description covers the calling semantics well but omits pageSize, the meaning of individual enum values, and any hint about the returned lead structure. Adequate for invocation but not fully complete.

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 20%, so the description must compensate — and it does, mapping nearly every parameter to a human concept: list (listId), label (labelId), status, verification (verify), ESP (esp), and search scope (email, name, company), plus sort direction. Only pageSize semantics and enum values are left undocumented.

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+resource ('List leads') and immediately scopes it with paging, default ordering, and the filter/search dimensions. It's clear enough to separate from list_lead_lists or list_campaigns, though it doesn't explicitly name a sibling it is not.

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 useful context on how to use it (paging, newest-first default, filter-by-field-or-search), which implies the filtering usage pattern. However, it never states when to prefer this over an alternative or any prerequisites / exclusion, so guidance is implied rather than explicit.

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