list_private_messages

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

With no annotations, the description carries the full burden of behavioral disclosure. It explains that the tool lists topics and defaults to the logged-in user, but it does not mention authentication requirements, read-only guarantees, pagination, or whether querying another user's private messages is permitted.

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 a single, front-loaded sentence with no filler. It states the action, the resource, and the default behavior efficiently.

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 simple one-parameter read tool, this is adequate but not complete. The absence of annotations and output schema means the description should ideally clarify return shape, pagination, and privacy/auth boundaries; those details are missing.

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?

The schema has 0% description coverage for the optional username parameter, but the description meaningfully explains it: it identifies the target user and clarifies that omitting it defaults to the logged-in user. This compensates for the bare schema, though it could add constraints like username format or permission limits.

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 uses a specific verb ('List') and a specific resource ('private-message topics of a user'), and it adds the useful default-scope detail ('defaults to the logged-in user'). This clearly separates it from siblings like send_private_message and list_notifications.

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 gives some usage context by explaining the default user, but it does not state when to prefer this tool over alternatives such as list_notifications or get_user_profile. No exclusions or alternative tool names are mentioned.

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