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

Annotations already provide destructiveHint=true, so the agent knows it mutates state. The description adds that the email is 'real' and mentions the API endpoint (POST /v1/transactional). However, it does not disclose potential failure modes, idempotency, or rate limits. Moderate beyond 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?

Two sentences plus a one-line API endpoint reference. The description is short and to the point, but the second sentence ('This dispatches...') is somewhat redundant with the first. No unnecessary 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?

The tool has no output schema, nested objects (attachments), and destructive behavior. The description fails to explain return values, error handling, or behavioral details like whether sending is synchronous. Gaps in completeness given the tool's 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?

Schema description coverage is 100%, so all parameters have clear descriptions. The description adds no extra parameter-level meaning beyond what the schema already provides. Baseline of 3 is appropriate as no additional semantic value is given.

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 states the tool sends a transactional email via a Loops template, using 'SENDS' and 'dispatches an actual email'. The title matches. However, it does not explicitly differentiate from sibling tools like loops_send_event, but the distinction is implied by the word 'transactional'.

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?

No guidance on when to use this tool versus alternatives (e.g., loops_send_event) or when not to use it. The description lacks context such as prerequisites or typical use cases. The only hint is the destructiveHint annotation indicating side effects.

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