List Proton folders

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the 'locally running Proton Bridge' dependency, which is useful context beyond annotations, but it does not add much behavioral detail beyond that. A 3 is appropriate given the annotation coverage.

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 a single, compact sentence that conveys the essential resource and scope without any filler or redundancy. It is appropriately sized for a zero-parameter, read-only list operation.

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 trivial zero-parameter listing tool with rich annotations and an output schema available, the description is complete. It states the source ('locally running Proton Bridge') and the resource ('folders'), and no additional call details are needed.

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 zero parameters, so there is no parameter semantics burden for the description to carry. The description correctly identifies what the returned folder list refers to, and the 100% schema coverage is trivial since the schema is empty.

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 states a specific verb ('List') and a clear resource ('folders exposed by the locally running Proton Bridge'). It is immediately distinguishable from sibling tools like list_messages, search_messages, and read_message, which operate on messages rather than folders.

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 makes the context clear: this tool lists folders available from the locally running Proton Bridge, so it should be used when the agent needs the folder collection before filtering or reading messages. It does not explicitly name alternatives, but no sibling tool targets folders, so the usage context is sufficient.

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