list_folders

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

Annotations already declare readOnlyHint and idempotentHint, so the read-only nature is covered. The description adds value by revealing that it queries the provider and by explaining the Graph vs IMAP identifier behavior, which is not present in the annotations or input schema.

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 tight and front-loaded: purpose, output shape, downstream usage, and read-only nature all fit in a few lines 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?

For a simple list operation with output schema, full parameter coverage, and strong annotations, the description supplies exactly the operational details an agent needs: what is listed, how to reference folders later, and that the operation is read-only.

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?

With 100% schema description coverage and a single optional account_id parameter, the schema already documents everything needed. The description does not add further parameter-level meaning, so the baseline 3 is appropriate.

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 opens with a specific verb and resource ('List the mailbox folders of an account') and names the output shape, so an agent can immediately distinguish it from sibling tools like list_messages or read_message. It also clarifies the folder identifier format (Graph id vs IMAP folder name).

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 tells the agent how to use the returned values as the folder/folder_id argument for other tools, which is practical context beyond the schema. It does not explicitly name alternatives or exclusions, but the purpose is clear enough that when-versus-when-not is mostly implied.

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