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

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is covered. The description adds meaningful context beyond that: parity with the web client's invite window and the underlying GET /v1/invites endpoint, which signals this is a pure, side-effect-free read of existing state.

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 sentences, no filler. The payload contents come first and the explanatory invite-flow context second, so the most important information is front-loaded.

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 need not be described, and the annotations carry the safety profile. The only small gap is that it doesn't state whether an invite code always exists or must first be generated, which an agent might need to know for a fresh account.

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 and the baseline of 4 applies. The description correctly implies the scope is implicitly the authenticated user's own invite link, with no filtering options to explain.

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 verb and resource: reads the invite link code, the players who joined through it, and the rewards earned. It also names its scope boundary by equating it with the web client's invite window (GET /v1/invites), so it is unmistakable against siblings like account or find_players.

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?

The second sentence explains the invite mechanism (someone passes your code as `invite` to register or guest_login), which tells the agent when this tool is relevant and how it relates to the registration tools. It stops short of explicit when-not-to-use guidance or naming a competing alternative, which is minor since no sibling overlaps.

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