List Message Analytics

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

Annotations already declare readOnlyHint and openWorldHint. The description adds valuable behavioral context: the response excludes specific sensitive data types and warns about personal data in contact_addresses and client_reference. This goes beyond the annotations.

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?

The description is extremely concise: one sentence stating the purpose and ordering, another listing exclusions and a data warning. Every sentence adds value with no wasted words.

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?

Given the presence of an output schema and annotations, the description covers the key aspects: what is returned, ordering, data exclusions, and privacy warning. It is complete enough for a simple list tool, though could mention pagination or that it's read-only (already covered by annotations).

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 50%; only limit and cursor have descriptions. The description does not add details for updated_after and updated_before, though it mentions ordering by updated_at which relates to these parameters. The description adds some context but does not fully compensate for the missing parameter descriptions.

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?

The description clearly states the tool lists an 'analytics-safe message projection' with explicit ordering by updated_at. It distinguishes itself from other list tools by emphasizing analytics safety and specifying excluded fields (subjects, BCC, headers, etc.).

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?

The description implies usage for analytics by highlighting that sensitive fields are excluded, but it does not explicitly state when to use this tool over alternatives like shipmail_list_messages or shipmail_list_threads. No exclusion or when-not-to-use guidance is provided.

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