Mark as Read

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

With no annotations, the description carries the burden, and it does reveal that this mutates IMAP flags and supports both read and unread states, implying reversibility via the read parameter. However, it does not disclose required permissions, whether marking read affects list_unread or other views, or what is returned on success or failure.

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 action-first sentence with no filler. Every word contributes to the operation ('Mark', 'messages', 'read or unread', 'IMAP FLAGS').

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 mutation with two required parameters, the schema plus description is mostly usable. Gaps include behavior when the optional folder is omitted, whether the change affects unread lists, and any return or error contract, especially since no output schema or annotations are provided.

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 covers all three parameters with descriptions (100% coverage), including the UID, the read boolean meaning true/false, and the folder. The description restates the read behavior and adds the IMAP FLAGS context, but it does not add syntax details, defaults, or edge-case semantics beyond the schema.

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 action ('Mark'), a resource ('messages'), and the possible states ('read or unread'), and adds the protocol mechanism 'using IMAP FLAGS.' It is unambiguous against siblings like fetch_email or list_unread, but it does not explicitly call out alternative tools or scope boundaries, so it stops short of the top score.

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 no guidance on when to use this tool versus siblings such as list_unread or fetch_email, nor any prerequisites, exclusions, or when-not-to-use conditions. The only inferable usage context is a direct restatement of the action itself.

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