messages-list

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

The description mentions that filtering happens in Elixir due to data storage, but it does not cover permissions, mutation side effects, rate limits, or return format. With no annotations, this is insufficient.

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?

Two sentences are concise and front-loaded with the core function. The second sentence about Elixir filtering is slightly technical but still short.

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?

With no output schema and zero annotations, the description covers basic listing but lacks details on pagination, ordering, error handling, and return structure. It is adequate but incomplete.

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 100%, so each parameter has a description. The description adds minimal context about default filtering behavior and implementation detail, which is helpful but not essential.

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 it lists messages received by the current user, with a default to unread messages in the personal Inbox case. It distinguishes from message sending/reading tools but does not explicitly differentiate from similar list tools like messages-read.

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?

No guidance on when to use this tool versus alternatives (e.g., messages-read). While it implies usage for listing, it lacks explicit context for when-not-to-use or prerequisites.

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