epost_unread_count

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

No annotations are provided, so the description bears the full burden of behavioral disclosure. However, it only states the tool returns a count, with no mention of authentication requirements, side effects, rate limits, or the format of the return value. For a read operation, these details are missing.

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 sentence, front-loaded, and contains no superfluous words. It could benefit from adding brief context without becoming verbose, but it achieves efficient communication of the core purpose.

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?

With no output schema and no annotations, the description is the sole source of information. It fails to specify what format the count is returned in, whether it requires being logged in (sibling epost_login suggests authentication), and if it's scoped to the current user. This lack of completeness could confuse an AI agent.

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?

There are no parameters, so schema coverage is trivially 100%. The description does not need to add parameter meaning, but it also does not explain what the tool returns or how to interpret the result. 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 clearly states the tool returns the count of unread letters in the inbox. It uses a specific resource (unread letters) and scope (inbox), and implicitly distinguishes itself from sibling tools like epost_list_letters which list the actual letters.

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?

No guidance is provided on when to use this tool versus alternatives. For example, it does not mention that for detailed unread letter info, one should use epost_list_letters with a filter. The description gives no when-not or alternative suggestions.

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