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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so safety is covered. The description adds genuinely useful scope context beyond that: it returns only one field of a larger configuration model and enumerates what that field holds (invite codes, attribution rules, milestones, per-side rewards), preventing the agent from expecting a full config object.

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?

The scoping statement is front-loaded in the first sentence, and the second sentence packs the field contents efficiently. The parenthetical example ('invite N friends → reward') is slightly verbose but earns its place by illustrating milestone semantics.

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?

There is no output schema, but the description compensates by describing the structure of the returned Referral configuration (invite codes, attribution, milestones, two-sided rewards, Reward references). For a one-parameter read tool with full annotation coverage, nothing critical is 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 the single parameter (title_id) is fully documented in the schema, so the baseline of 3 applies. The description adds nothing about the parameter itself.

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+resource ('GET ONLY the Referral field') and identifies the exact location of the data (TitlePublicConfigurationModel), so the agent knows precisely what is returned. It implicitly separates itself from save_referral and get_reward ('Reward bundles reference Reward'), though it never names those siblings outright.

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?

'GET ONLY' implies read-only access and scoping versus the sibling save_referral, but there is no explicit when-to-use/when-not guidance or named alternative. Usage is only inferable from the contrast between get_ and save_ tool families.

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