List folders and labels

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows it's a safe read. The description adds the 'Call this first' ordering and the purpose of learning names, but does not disclose additional behavioral details like pagination or response format. This is acceptable given annotation coverage, but not rich.

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, no wasted words. The first sentence states the core functionality, the second provides usage context. Each 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?

For a simple parameterless discovery tool with annotations, this is complete. It tells the agent what the tool returns (list of folders/labels) and why to use it (to learn exact names for filing/tagging). No output schema exists, so the description adequately covers what the agent needs to select and invoke the tool.

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 0 parameters, so the schema fully covers parameter semantics. Per the rubric, 0 params earns a baseline of 4. The description adds nothing parameter-related, but none is 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 uses a specific verb ('List') with a clear resource ('all Proton folders and labels') and scope ('available over the Bridge'). It also distinguishes from siblings by being the discovery tool for names, unlike create_folder_or_label or delete_label which perform different actions.

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 provides clear context: 'Call this first' to learn exact folder/label names before filing and tagging. It does not explicitly name alternatives or exclude cases, but the instruction to call first is a useful usage guideline for a discovery tool.

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