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

Annotations already declare non-read-only, non-idempotent, open-world behavior, but the description adds critical operational detail: 500-point cost, login requirement, daily cap, midnight expiry, no auto-redeem, specific error codes with retry guidance, timeout verification to prevent duplicates, and the fact that existing conversations do not consume quota.

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 description is dense but front-loaded: login requirement, user confirmation, cost, limits, error handling, alternatives, and chain are all packed into a compact block with no filler. Every sentence carries operational meaning.

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?

Given a zero-parameter mutation with no output schema, the description covers prerequisites, constraints, failure modes, non-retry conditions, duplicate-prevention advice, and the surrounding workflow. Nothing essential for correct invocation appears 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?

This tool takes no parameters, so the schema cannot document any. The description adds contextual cost and quota semantics but has no parameter-level details to clarify beyond the baseline for zero-parameter tools.

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 description states a precise verb and resource: redeem points for one new chat opening today. It distinguishes the action from related tools by naming get_my_invite for long-term quota and start_conversation as the downstream step.

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 explicitly requires login and user confirmation before redeeming, forbids automatic redemption, states the daily limit and midnight expiry, and routes long-term quota needs to get_my_invite. The combination chain further clarifies order of operations.

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