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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe read operation. The description adds the scope ('linked to this install') but does not disclose additional behavioral traits such as whether it returns connection status, whether it requires prior authentication, or any rate limits. With annotations covering the safety profile, a 3 is appropriate.

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?

The description is a single, concise sentence that front-loads the purpose. It contains no fluff and is appropriately sized for a simple listing tool.

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?

Given the tool's simplicity (one optional param, no output schema), the description is mostly adequate, but the lack of parameter semantics and any mention of return format or filtering behavior leaves gaps. The annotations cover safety, but the description does not fully compensate for the undocumented parameter.

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 has one optional parameter 'account' with no description, and the description does not explain what 'account' means or how it filters results. Schema description coverage is 0%, so the description must compensate, but it does not. The parameter semantics are entirely unclear, leaving the agent to guess whether 'account' is an ID, name, or filter.

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 Anthropic Billing admin API connections linked to the install. It uses a specific verb ('List') and resource ('Anthropic Billing admin API connections'), and it distinguishes from siblings like anthropic_billing_cost and anthropic_billing_usage, which are about data retrieval rather than connection listing.

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 description implies usage for viewing existing billing connections, but it does not explicitly state when to use this tool versus alternatives. It does not mention prerequisites like authentication or whether it should be used before other billing tools. The context is clear but lacks explicit guidance on when not to use it or alternatives.

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