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

Annotations already cover the read-only profile, yet the description adds substantial context beyond them: no side effect on listing ('Listing does not mark anything as seen'), the epistemic status of the data ('a suggestion, not a verified identity'), and explicit safety handling for aliases as untrusted human-authored strings. This is exactly the extra behavioral value the dimension rewards.

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?

Front-loads the returned resource, then the parameter conditional, then the conceptual definition, then safety rules. Every sentence carries weight and the ordering is logical, though the safety tail is dense enough to make the whole slightly long.

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 fields needn't be explained, and the description nonetheless covers semantics, side effects, and trust/safety. The only real gap is pagination behavior for limit and cursor, which an agent may need to iterate results.

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 carry parameter meaning. It explains new_only well ('not yet acknowledged') but says nothing about limit or cursor, leaving pagination behavior entirely undocumented in both schema and description.

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 ('People from the human's address book who are on netsi and can be invited') and enumerates the returned fields. It implicitly distinguishes itself from ack_address_book_matches via 'Listing does not mark anything as seen,' but never names or explicitly contrasts the sibling.

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?

Offers a conditional for one parameter ('Pass new_only to see only those not yet acknowledged') and hints that a separate acknowledge step exists, but never states when to choose this over list_address_book, list_contacts, or ack_address_book_matches. Usage is implied rather than directed.

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