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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered. The description adds nothing on top of that: no pagination behavior, no ordering, no indication of whether deprecated labels are included. It essentially restates the title.

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?

A single short sentence with no filler and the resource front-loaded. It is not padded, though it is arguably under-specified rather than merely concise.

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?

A zero-required-parameter read tool with full annotation coverage and no output schema needs little prose, so the bar is modest. Still, the description omits return shape and pagination, leaving it only minimally adequate for an agent to call confidently.

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 100% and the single 'fields' parameter is well documented in the schema itself ('return only these fields of each record') with an enum of valid values. The description contributes no additional parameter meaning, so the baseline 3 applies.

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 verb and resource ('List the conversation labels') and scopes it to 'this account', which partially distinguishes it from label-listing siblings. However, the crowded sibling set (list_all_labels_of_a_conversation, list_all_labels_of_a_contact, list_conversation_messages) makes the phrasing 'conversation labels' ambiguous about whether these are label definitions or per-conversation associations.

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?

There is no when-to-use guidance, no exclusions, and no pointer to alternatives such as list_all_labels_of_a_conversation. The agent must infer from the name alone that this returns the account's label catalog rather than labels applied to a conversation.

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