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

Annotations already establish a safe read (readOnlyHint=true, destructiveHint=false), so the bar is lower, yet the description adds real context: every referral is human-reviewed, pending ones are not earned rewards, and customer identities are deliberately unavailable on this surface. That privacy/interpretation context is genuinely beyond the annotations.

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 what the tool returns, followed by two short caveats. Each sentence earns its place, though the final clause is slightly wordy.

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?

An output schema exists so return values needn't be fully explained, yet the description still flags the key returned concepts (milestone, review state) and the identity limitation. Adequately complete for a read-only list tool, with only the alternative-routing guidance missing.

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 all six parameters (including the three enums) are already documented in the schema, so the baseline is 3. The description adds no filter syntax or usage detail beyond what the schema provides.

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?

States a specific resource ('the referrals credited to this affiliate') and adds what is returned — milestone reached and review status. The 'my_' prefix plus the resource clearly separates it from sibling tools like my_earnings and my_service_links.

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?

Usage is implied (use when the affiliate asks about their own referrals) and the 'pending is not an earned reward' note is a useful interpretive cue, but no sibling alternatives are named and no when-not-to-use condition is given.

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