proton_list_emails

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

With no annotations, the description carries the full burden, and it only partially discharges it. It does disclose ordering ('newest first') and the start of a return-field list ('id, sender, recipients, sub...'), which is genuine behavioral value, but it says nothing about which folder is used given the tool takes no arguments, whether authentication/connection is required, or whether results are capped/paginated.

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?

What is present is front-loaded and free of padding, so it would score highly on efficiency. But the text is visibly truncated mid-word ('recipients, sub...'), so it reads as an incomplete definition rather than a deliberately tight one.

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 zero-parameter, no-annotation, no-output-schema tool, the description is the only place to learn the default folder, the connection/auth prerequisite, and any result limits, and it covers none of these. The truncated field list hints at return values but does not finish the job.

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 input schema declares zero parameters, which is the baseline-4 case under the rubric. However, the description's phrase 'one folder' implies a folder selector that the schema does not expose, leaving how the target folder is chosen unexplained.

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 names a specific verb and resource ('Lists the newest messages of one folder of a Proton Mail account') and adds the ordering ('newest first'), so an agent can distinguish it from proton_read_email or proton_send_email. It falls short of 5 because it never explicitly contrasts itself with the sibling proton_search_emails, which is the obvious alternative for the same mailbox.

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?

There is no when-to-use guidance at all: nothing says to prefer this over proton_search_emails when you have no query, or to use proton_read_email once you have an id. The only implicit cue is 'newest messages', which is not a usage rule.

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