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

There are no annotations, so the description carries the transparency burden. It discloses a cost ('Cost = 10 tokens') and return value ('Returns the created redirect URL'), but does not mention permissions, reversibility, or other side effects beyond the implicit mutation.

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 four succinct sentences, front-loaded with the core purpose. It includes token cost and return behavior without any wasteful or repetitive text.

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 two-parameter create tool with an output schema and full parameter descriptions, the description provides the necessary prerequisites and selection logic. It lacks comparative guidance against siblings but is otherwise complete.

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 covers 100% of parameters, so the baseline is 3. The description reinforces the schema's guidance for clerk_instance_id but adds no new parameter-level detail beyond what the schema already states.

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+resource: 'Add an allowed redirect URL to a connected Clerk instance.' This clearly distinguishes it from the many other create_* tools and states exactly what is being created.

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 a clear prerequisite ('Call clerk.get_connected_accounts first') and explains how to target a specific instance or use the default account. Without an explicit alternative or when-not-to-use, it stops short of the highest bar but offers clear context.

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