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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes beyond them by disclosing the authentication requirement, that pagination is bounded, and what the result is useful for (saved IDs for default-sender selection). It adds real context rather than repeating the safety hints.

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?

Short and front-loaded, which is good, but it is a run of clipped fragments ('Use nextCursor as before', 'No mailing') whose meaning depends on unspecified prior context. Brevity here costs clarity rather than earning its place.

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?

An output schema exists so return values needn't be spelled out, and the auth requirement is disclosed. But for a tool with three undocumented parameters and a cursor whose name doesn't match the description, the definition leaves too much for the agent to infer before calling it correctly.

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 0%, so the description must compensate, and it largely doesn't: limit, search, and before are never explained. Worse, it instructs 'Use nextCursor as before' while the actual parameter is named 'before', so the guidance mismatches the schema and can actively mislead an agent wiring up pagination.

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 or search the workspace address book') and bounds the operation ('with bounded pagination'), which separates it from validate_address among siblings. The remaining scope notes ('No mailing') reinforce it but the phrasing is fragmentary rather than a clean statement.

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?

'No mailing' implies a when-not, and 'Returns saved IDs for default-sender selection' hints at the downstream use case. However, no sibling is named and there's no explicit statement of when to choose this over validate_address or list_cover_sheets, so selection guidance is only implied.

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