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

Annotations already declare the mutation profile (readOnlyHint false, destructiveHint false), but the description adds meaningful behavior beyond them: the test user is one-hour, is never counted, and its rows and files are deleted afterward. It does not cover permissions or rate limits, but the ephemeral lifecycle and cleanup are well disclosed.

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 efficiently structured sentence that front-loads the action and uses a concise parenthetical for the important lifecycle caveats. No sentence is wasted.

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?

An output schema exists, so the return value needn't be fully explained, but the description still helpfully names signin_url. However, for a two-parameter tool with 0% schema description coverage, the missing meaning of 'site' and 'plan' leaves a meaningful gap.

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?

There are two parameters with 0% schema description coverage, so the description carries the full burden of explaining them. It does not define what 'site' identifies or what 'plan' controls; it only describes the tool's overall effect.

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?

States a specific verb and resource ('Makes a one-hour test user') plus the outcome ('returns signin_url to see the app as a user'). It is clearly distinct from read/list tools, but it does not explicitly name alternatives such as invite_users to rule them out.

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 phrase 'to see the app as a user' implies the use case, but there is no explicit when-to-use guidance, no exclusions, and no comparison against sibling tools like invite_users or email_users. Usage is inferred rather than stated.

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