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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds value beyond that by enumerating the return payload — referral code, sign-ups, paid referrals, and rewards split into applied vs pending — which matters because there is no output schema. It does not mention whether a coach without a program gets an empty result, but the disclosure of return fields is substantive.

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?

One compact sentence, front-loaded with the resource and followed by the enumerated return fields. Nothing is redundant or padded.

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?

With no parameters, no annotations beyond readOnly, and no output schema, the description carries the burden of describing the result and does so by listing the reward states. The only gap is not saying what happens when no referral program exists, which is minor for a read-only lookup.

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 tool takes zero parameters, so the baseline of 4 applies; the description correctly implies no filtering arguments are needed since it scopes implicitly to 'the coach's' own program.

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 names a specific resource (the coach's referral code) and the associated results (sign-ups, paid referrals, rewards), which clearly separates it from sibling analytics tools like get_my_rating_summary or get_coach_dashboard_stats. It lacks an explicit verb, but 'get_my_referral_program' plus the content list leaves no ambiguity about what is returned.

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?

There is no statement about when to call this versus related stats/dashboard tools, no prerequisites, and no exclusions. The agent must infer usage from the name alone.

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