list_folders

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

With no annotations provided, the description carries the full burden. It discloses return format ('array of folders, each with id, name, messageCount, and unreadCount'), parameter effect ('grouped by account'), and error condition ('Returns an error if Outlook is not running'). These are all meaningful behavioral traits beyond the 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 four sentences, each earning its place: purpose, use case, return format, and error handling. It is front-loaded with the core action and is efficiently structured without unnecessary words.

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 tool's simplicity (one optional parameter, no output schema, no annotations), the description covers all necessary context: behavior, return fields, parameter effect, and failure mode. It fully equips the agent to invoke the tool correctly and interpret results.

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% and includes a detailed description of account_id. The description adds the behavioral effect that providing account_id returns folders grouped by account, which is not in the schema and clarifies the output. This goes beyond the baseline of 3 for high schema coverage.

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 lists all mail folders in Outlook with counts, and explicitly connects it to other tools needing folder IDs, distinguishing it from sibling list tools. The verb 'list' plus resource 'mail folders' is specific, and the usage context differentiates it from list_accounts, list_calendars, etc.

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?

It explicitly tells when to use the tool: 'Use this to discover folder IDs needed by list_emails, search_emails, prepare_move_email, and other folder-based tools.' This provides clear alternatives and purpose, fulfilling the when-to-use and implied when-not-to-use criteria.

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