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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely useful domain behavior — the 25% commission rate and the 12-month earning window — which is context the annotations cannot convey, but says nothing about payout timing, currency, or whether earnings are live vs settled.

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?

Two short sentences, front-loaded with the returned artifacts before the commission detail. No padding, though the trailing phrase '12 months each' is elliptical and slightly ambiguous about which period it qualifies.

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 no-param, read-only, no-output-schema tool, listing the fields returned plus the earning rule is close to sufficient. It stops short of describing the response shape (e.g., counts, totals, link format), which would be the only remaining 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the 100% schema coverage is trivially satisfied. Baseline 4 applies for a no-parameter tool.

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?

Names a specific resource set the agent will receive: referral code, link, referred agents, and earnings. It is distinguishable from siblings like start_earning, how_to_earn, and invite_friends, though it never uses an explicit verb ('returns your ...') to frame it as a read.

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 when-to-use guidance and no mention of alternatives such as start_earning, how_to_earn, or invite_friends. The agent must infer from the noun list that this is a dashboard-style lookup rather than an action tool.

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