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

With no annotations, the description carries the behavioral burden. It discloses the Proof account authentication prerequisite, warns that start_login will not open the tool, and explains that declared member channels are stored for later enrollment. It does not describe the return value or other side effects, but the key operational behaviors are covered.

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?

Three short paragraphs with no filler: the definition is front-loaded, the workflow is isolated under 'Agent usage', and the authentication caveat is clearly separated. Every sentence contributes either to understanding the resource or calling it correctly.

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 create tool with no output schema and no annotations, the description covers the essential context: what a Circle is, how to seed members, what to do next, and the auth precondition. It falls just short of perfect because it does not mention what the tool returns, such as the Circle ID an agent would likely need for add_circle_member or invite_circle_member.

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 schema already documents 100% of the parameters, so the baseline is 3. The description adds value by explaining that members are optional initial seeds, that declared channels are stored so members can later be invited to enroll, and by linking parameters to the follow-up workflow.

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 opens with a specific verb and resource: 'Create a Circle' and defines it as a named group of trusted contacts powering Proof-Me and Approvals-on-Circle. This clearly distinguishes it from the many sibling tools and explains the optional members-seeding behavior.

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 'Agent usage' paragraph gives an explicit workflow: create the Circle, add members via add_circle_member or seed them here, then invite_circle_member to mint the enrollment deep link. The ACCESS note also clarifies when not to use this tool, stating that start_login does NOT open it.

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