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

Annotations already declare non-readOnly, non-idempotent, destructive behavior, so the description's real contribution is the consent semantics: this does not add the member directly, it sends an invitation that must be accepted. That is important context an agent could otherwise get wrong. It does not mention duplicate-invite behavior, permissions, or rate limits, so not a 5.

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 short sentences with zero filler, front-loading the usage trigger before the behavior. Every clause carries information the agent needs.

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?

With an output schema present, return values need no explanation, and all four parameters are documented. The remaining gap is that the description never clarifies how the invitee is identified given that only circle_id is required, leaving the contact_id/connection_id selection entirely to the schema.

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%, with each of the four parameters (note, circle_id, contact_id, connection_id) documented inline, including the contact_id vs. connection_id distinction. The description adds no parameter-level meaning beyond the schema, so the baseline 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 states a concrete verb+resource (creates a consent invitation) and gives the outbound effect ('the invitee must accept'), which is more than a restatement of the name. It does not explicitly differentiate itself from near-neighbors like connections.invite or circles.members.remove, so it stops short of a 5.

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?

Provides a clear trigger condition — 'When the human wants to add someone to a circle' — which tells the agent exactly the situation that selects this tool. It offers no when-not guidance and names no alternative sibling, so it misses the top band.

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