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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds useful scope context about 'generated-app runtime users' but does not disclose return format, pagination, or other behavioral details. With annotations carrying the safety burden, the added context justifies a 3.

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 concise sentences with no wasted words. The purpose is stated first, and the distinguishing note is placed second. Every sentence 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?

For a simple single-parameter read-only list operation, the description covers the essential scope and distinguishes it from collaborators. It doesn't mention return shape or pagination, but given the simplicity and annotation coverage, it is largely complete. A 4 reflects that minor 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?

The single parameter app_id is fully described in the schema with 'The app ID' at 100% coverage. The description does not add any additional param semantics or format details, so the baseline of 3 applies.

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 lists 'generated-app runtime users/members' for an app, a specific verb and resource. It also distinguishes this from 'Studio project collaborators', helping differentiate from related tools like invite_app_member or remove_app_member.

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?

It provides context by specifying this is separate from Studio project collaborators, implying when not to use it. However, it does not explicitly name alternatives or describe conditions for choosing this tool over other member-related tools, though the distinction gives a helpful exclusion.

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