find_email_folder

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

The description goes beyond the readOnlyHint annotation by explaining the return behavior ('Returns the real folder path to use as sourceMailbox') and its role in subsequent operations. It does not contradict the annotation and adds useful context about the tool's purpose and output, though it does not detail error cases or other behavioral nuances.

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 two sentences, front-loaded with the core purpose, and every sentence earns its place. It states what the tool does, when it's needed, and what it returns, with no redundancy or filler.

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?

This is a simple read-only utility with a clear purpose, complete parameter schema, and no output schema. The description covers what the tool does, when to use it, and the nature of its return value, making it fully self-contained for an agent to select and invoke correctly.

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 provides 100% coverage with meaningful descriptions for all three parameters, so the baseline is 3. The description adds a relationship note: the returned path is used as sourceMailbox for move/delete, which is helpful but does not substantially alter the parameter understanding beyond what the schema already 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 function: 'Find which real mailbox folder(s) an email belongs to.' It uses a specific verb ('Find') and resource ('real mailbox folder(s)'), and distinguishes it from siblings by noting it is a required prerequisite for move_email and delete_email when the email is in a virtual folder. This is highly specific and unambiguous.

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 explicitly states when to use the tool: 'Required before move_email or delete_email when the email was found in a virtual folder (e.g., "All Mail", "Starred").' This gives clear context and includes examples, making it evident when this tool is necessary and when it might not be (though not explicitly stated, the condition is clear).

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