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

Annotations only indicate readOnlyHint=false and openWorldHint=true. The description adds meaningful behavioral constraints: the recipient is always the current user, the tool cannot email anyone else, and it cannot send custom or user-authored content. This goes beyond the annotation data and prevents misuse.

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 compact and front-loaded, stating the core action in the first sentence and then adding important restrictions and usage guidance. Every sentence earns its place with no redundancy.

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 utility tool with three well-documented parameters and no output schema, the description provides all necessary context: what it does, who can receive the email, what content can be included, and when to use it. Nothing critical is missing.

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 description coverage is 100%, and each parameter already has a clear description. The tool description adds general context about the recipient and email restrictions but does not add new parameter-level meaning beyond what the schema provides. A baseline of 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 uses a specific verb+resource: 'Email a finished file to the signed-in user's OWN email address.' It clearly states the tool's scope and its key limitation (cannot email anyone else), so an agent can distinguish it from the broader utility and sharing toolset.

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 explicitly says 'Use ONLY when the user explicitly asks to have a result emailed to them.' This gives a clear, actionable condition for when the tool should be selected and rules out using it for emailing other people or sending custom content.

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