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

Annotations already declare readOnly, non-destructive, and closed-world behavior. The description adds meaningful context beyond that: conversation ticket permissions are required, an unstarted conversation returns an empty list, and staff notes are excluded because they are activities. This adds auth and edge-case transparency, though no rate-limit or pagination behavior beyond the schema.

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?

Four short sentences, front-loaded with the core purpose and required parameter. The permission note and empty-list edge case follow logically, and every sentence carries useful 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 6-parameter list tool with nested filters and no output schema, the description covers the key non-schema behaviors: permissions, empty-conversation return, and staff-note exclusion. It does not describe the returned message shape, but with rich sort/filter field lists in the schema and no output schema, that omission is minor.

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%, so parameters are already fully documented. The description reiterates that deal_id is required and that filtering, sorting, and pagination are supported, but adds no syntax or semantic detail beyond what the schema provides. Baseline 3 is appropriate.

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 client-facing messages in a deal conversation.' It distinguishes itself from deal-message-write by being a read, and from deal-activity-read by noting 'staff notes are activities.' An agent can identify the tool's purpose without opening the schema.

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 clear context: requires deal_id, supports filtering/sorting/pagination, and conversation ticket permissions apply. The clause 'staff notes are activities' implicitly routes staff-note queries to deal-activity-read. It stops short of explicitly naming that alternative or other sibling message tools, so it is not a full when/when-not guide.

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