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

No annotations are provided, so the description carries the burden. It discloses a concrete behavioral trait: 'Cost = 2 tokens' and implies performance trade-offs (cheaper). However, it doesn't mention auth requirements or error conditions, which are common for Clerk tools, but for a simple count it's reasonably transparent.

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 sentences, front-loaded with the primary purpose, followed by actionable usage steps and cost. Every sentence provides unique value with no padding.

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 (count operation, two optional params, output schema present), the description fully covers the essential guidance: prerequisite, default behavior, cost advantage, and parameter handling. It is complete and self-sufficient.

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 coverage is 100% and descriptions already explain both parameters, but the tool description adds useful context: 'clerk_instance_id' targets a specific connection and omitting uses the default account, plus 'query' is for optional filtering. This enriches the meaning beyond raw schema.

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 'Return the total number of users in a connected Clerk application' with a specific verb and resource. It distinguishes itself from sibling tools like clerk.list_users by emphasizing it only returns a count, not the list.

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 explicit usage guidance: 'Call clerk.get_connected_accounts first' is a clear prerequisite, and explains when to pass or omit clerk_instance_id. Also states a decision heuristic: 'Cheaper than listing users when you only need the total count' directly contrasts with the alternative clerk.list_users.

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