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

The description adds minimal behavioral context beyond the tool's name: it indicates both mailboxes are fetched at once. It does not disclose return format, ordering, deduplication, pagination, authentication requirements, or any other notable behaviors. With no annotations to fill the gap, this is a significant deficiency.

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, concise sentence with no wasted words. It front-loads the primary function and is easily scannable.

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 tool with no parameters and no output schema, the description provides the core function but does not explain what the unified result looks like or how it differs from calling two separate inbox tools. It is adequate but relies heavily on the tool name and sibling context for full understanding.

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 tool has zero parameters, so the description is not required to explain parameter syntax or meaning. The baseline of 4 applies; the description adds nothing about parameters but none are needed.

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 fetches Gmail and Outlook simultaneously, which identifies its purpose and distinguishes it from single-mailbox tools like get_inbox and get_outlook_inbox. However, it omits the word 'inbox' explicitly, relying on the tool name to convey the resource type.

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 is given on when to use this tool versus alternatives. The phrase 'simultaneously' implies it combines both Gmail and Outlook, but it does not explicitly mention when to choose it over get_inbox or get_outlook_inbox, nor does it mention any exclusions or prerequisites.

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