list_messages

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool lists messages and defaults to INBOX, but lacks critical details such as whether this is a read-only operation, how 'recent' is defined, pagination behavior, error conditions, or authentication requirements. For a tool with zero annotation coverage, 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?

The description is highly concise and front-loaded: a single sentence efficiently conveys the core action, resource, returned fields, and default behavior. Every word earns its place with no redundancy or unnecessary elaboration, making it easy for an agent to parse quickly.

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 lack of annotations and output schema, the description is incomplete for a tool that interacts with message data. It doesn't explain what 'recent' means, the format of returned messages, error handling, or how it differs from siblings like 'search_messages'. For a read operation with no structured output documentation, more context is needed.

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 description coverage is 100%, so the schema fully documents both parameters (folder and limit). The description adds minimal value by mentioning the default folder is INBOX, which is already in the schema's default field. It doesn't provide additional context like folder path examples or limit usage scenarios beyond what the schema offers.

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's purpose: 'List recent messages in a folder' specifies the verb (list) and resource (messages), and 'with subject, from, date' indicates the returned fields. However, it doesn't explicitly differentiate from sibling tools like 'search_messages' or 'get_message', which prevents a score of 5.

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 provides minimal usage guidance: it mentions the default folder is INBOX, but offers no advice on when to use this tool versus alternatives like 'search_messages' or 'get_message'. There's no mention of prerequisites, exclusions, or comparative contexts, leaving the agent with little direction.

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