fastmail_mark_email_read

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

With no annotations, the description itself carries the behavioral burden; it plainly states that the tool toggles read state in either direction. However, it does not disclose auth requirements, idempotency, error behavior, or whether the operation is reversible/side-effect-free, so disclosure is only partially complete.

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?

A single short sentence contains the full core behavior with no filler or repetition. Every word earns its place.

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?

The tool is a simple two-parameter state toggle; the description plus schema sufficiently covers correct invocation. It lacks response/error details, but those are not essential for selecting and invoking this tool correctly.

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 coverage is 100%, so the baseline is 3. The description adds no parameter-level meaning beyond the schema; the read parameter's own description already explains true/false, and emailId is self-explanatory.

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 uses a specific verb ('mark') and resource ('email') and names the exact state ('read or unread'), which clearly distinguishes it from the sibling fastmail_mark_email_flagged. An agent can tell at a glance what this tool does.

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 gives no guidance about when to choose this tool over alternatives or any prerequisites/exclusions. It never mentions fastmail_mark_email_flagged or how read-state changes differ from other email operations, so the agent must infer usage solely from the operation name.

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