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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, but the description adds genuinely non-redundant behavior: the URL is auto-issued upon payment confirmation, a call can trigger issuance, and the 5% earning rate is explained. It also covers the auth variant (personal token URL → omit customerKey). It does not state whether repeated calls regenerate the URL or what the response contains, keeping it below 5.

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?

Purpose is front-loaded in the first sentence, and the issuance condition follows logically. The 5% commission sentence is useful motivation rather than filler, though the description is denser than strictly necessary for a lookup with an issuance side effect.

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?

There is no output schema, so the description carries the burden of indicating the return — 'call this to see it again' implies the URL is returned, though the exact response shape is unspecified. With zero required parameters and full schema coverage, this is close to complete; only the response form is a gap.

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%, so the schema already documents all three optional parameters, establishing a baseline of 3. The description largely restates the schema's customerKey guidance ('omit customerKey' for personal token URLs) and adds no detail on how name or contact affect the referral record. No semantic value beyond the structured fields.

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: 'Look up your GYOTAK referral MCP URL', and adds the important nuance that the same call may issue a URL if none exists yet. That distinguishes it functionally from the name 'apply_referrer', which alone would suggest only an application action. It does not explicitly differentiate itself from sibling tools like my_referrals or get_share_kit.

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?

Clear context is given for when to call: the URL arrives in the payment confirmation email, and this tool is how you 'see it again'. The condition 'If you have a paid order but no URL yet, one is issued now' further clarifies eligibility. No explicit exclusions against sibling tools such as my_referrals, so it falls short of a 5.

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