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

No annotations are provided, so the description carries the full burden. It states 'Returns the redirect URL' and notes 'Cost = 3 tokens,' adding useful behavioral details beyond the schema. It implies a read-only operation via 'Retrieve,' though it does not mention error handling or authentication requirements, which prevents a perfect score.

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 purpose, and no fluff. Every line earns its place: purpose, prerequisite/usage, return value, and cost. This is a model of concise, structured description.

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 simple get-by-id tool with an output schema and 100% parameter coverage, the description covers the essential usage steps, including the prerequisite connected-account lookup and optional instance targeting. It could have mentioned how to discover available redirect URL ids (e.g., via list_redirect_urls), but that is a minor gap given the clarity of the operation.

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% with both parameters already described, including the clerk_instance_id default behavior. The description rephrases the clerk_instance_id usage but adds no new syntax or format details beyond what the schema already states. This meets the baseline for high schema coverage, but the description's added value is minimal.

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 'Retrieve an allowed redirect URL by id from a connected Clerk instance,' clearly specifying the verb, resource, and scope. This distinguishes it from sibling tools like list_redirect_urls (list all), create_redirect_url, and delete_redirect_url by the by-id retrieval focus.

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 instructs 'Call clerk.get_connected_accounts first,' providing a clear prerequisite. It also explains when to pass clerk_instance_id versus omit it, which is useful context for selecting the right connected account. However, it does not explicitly contrast with list_redirect_urls or other alternative tools, so it stops short of full alternative differentiation.

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