mark-as-unread

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

With no annotations, the description discloses it returns confirmation and the action is a state change. Lacks details on permissions or side effects, but sufficient for a simple mutation.

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?

Four short sentences, each with a clear purpose: usage condition, return value, exclusions, prerequisite. No fluff.

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 single-parameter tool with output schema and good description, it covers input, output, alternatives, and prerequisites completely.

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?

Schema has 0% description coverage and a complex pattern. The description mentions 'by id' and how to get it, but does not explain the id format (digits or imap: prefix). Adds context but incomplete.

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?

Clearly states the tool marks a single message as unread by id, and distinguishes from batch operations and mark-as-read.

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?

Explicitly provides when to use (single message), when not to use (batch or marking read), and where to obtain the id (search-messages or list-messages).

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