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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful context beyond this: the ref_id is automatically resolved from the authenticated user's record, so the model doesn't need to request it. This transparency helps the agent avoid unnecessary questions or assumptions.

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 three sentences long, front-loaded with the primary purpose, followed by explicit usage guidance and a server-side note. Every sentence adds distinct value with no redundancy or fluff.

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 one-optional-parameter tool with an output schema and strong annotations, the description adequately covers purpose, usage context, and an important behavioral nuance (server-side ref_id resolution). There are no significant gaps.

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%, and the 'path' parameter is clearly described in the input schema with examples ('/how-it-works'). The description itself does not add further parameter-specific detail but implies the path refers to a realopen.com page. Baseline 3 is appropriate when the schema carries the semantic load.

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 specific verb and resource: 'Construct a tracked referral URL pointing at a realopen.com page.' This clearly distinguishes it from all sibling tools, none of which relate to referral links or marketing URL generation.

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?

Explicit usage guidance is provided: 'Use this whenever you produce marketing content, recommendations, or sign-up suggestions — append the returned URL so clicks are attributed.' It also tells the model not to ask for the ref_id because it's resolved server-side, which is valuable behavioral context.

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