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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely new behavioral context: the bonus grant lifecycle (invited org gets a welcome bonus; inviter gets another on first successful Sandbox publication), that bonuses are traffic not cash, and that merely reading or applying a code does not start traffic.

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 and scope are front-loaded in the first sentence, with mechanics following. Nearly every sentence adds decision-relevant detail, though the bonus-application walkthrough is somewhat long relative to a no-parameter read tool.

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 output schema available, the description carries the burden of describing returns and does so (invitation.url, counts, bonuses), plus eligibility rules and the downstream start_sandbox_traffic workflow. An agent has everything needed to call it and act on the result.

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 no parameter surface to document; baseline is 4. The description instead describes an output field (invitation.url) and the bonusId consumed by a sibling tool, which is useful but not parameter semantics per se.

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 opening sentence names a specific verb (Read) and enumerates the exact resource contents: stable invitation code/link, eligibility, aggregate invitation counts, and available traffic bonuses. It is clearly distinguishable from the sibling apply_referral_code, which mutates state.

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?

It states the tool is read-only sharing ('share the returned invitation.url'), explicitly notes there is no enrollment step, and routes the agent to alternatives: read get_sandbox_traffic, then call start_sandbox_traffic with bonusId instead of postUrls. The eligibility boundary (accept until first-ever Sandbox publication) tells the agent when the program still applies.

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