List folders / labels

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond annotations: it returns counts, describes provider-specific differences (path as opaque id vs name as hierarchy), and clarifies that it operates on a single account.

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?

Two sentences with no wasted words. The core function is front-loaded, and the second sentence provides a valuable provider-specific caveat. Every sentence earns its place.

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?

There is no output schema, so the description's mention of counts, path, and name partially compensates. It also gives cross-provider context and clarifies the relationship to other tools. It doesn't mention pagination or error conditions, but for a simple read-only list tool with one parameter, the description is nearly complete.

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 single parameter 'account' is fully documented in the schema with 'Account id from list_accounts' (100% coverage). The description doesn't add extra parameter-level detail; the provider-specific path/name semantics relate to the output, not the input. 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 uses a specific verb ('Lists') and resource ('folders (labels on Gmail)') and scopes it to 'one account' with 'message and unseen counts'. This clearly distinguishes it from sibling list tools like list_accounts and list_uploads, and even clarifies the Gmail vs Outlook naming nuance.

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 gives concrete guidance on how the returned values should be used by other tools ('either one can be passed to the other tools as a folder'), and explains the meaning of path and name for Outlook. It doesn't explicitly state when not to use it or name an alternative, but the usage context is clear and the sibling set makes the purpose obvious.

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