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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=true, which inform the agent of safe, idempotent behavior. The description adds context about the data returned (last event, timestamps) but does not contradict annotations. It adds minimal value beyond the annotations.

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 concise sentence that includes the verb, resource, scope, and data returned. No unnecessary words, clearly front-loaded.

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 lookup tool with one parameter and an output schema (not shown but present), the description is sufficiently complete. It explains what the tool does and what data it returns, though it could mention the event timestamps more explicitly. Slightly above baseline due to low complexity.

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 has 100% description coverage for the single parameter (email_id with example). The description references 'by ID' but adds no new semantic information beyond the schema. 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 specifies the action (Check delivery status), the resource (a sent email by ID), and the data returned (last event, timestamps). It effectively distinguishes from sibling tools like email.transactional.send which creates emails.

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 implies usage after sending an email (by referencing 'Email ID returned from send_email'), but does not explicitly state when to use this tool versus alternatives (e.g., email.transactional.send for sending) or mention exclusions (e.g., only for transactional emails).

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