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

Annotations already indicate a safe read-only operation, and the description adds meaningful behavioral context: certificates expire unused, near-expiration should be surfaced proactively, and coverage for a specific hotel must not be inferred from the cap. This goes well beyond the structured annotations without contradicting them.

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 longer than average, but every sentence earns its place: it defines the resource, lists return contents, gives routing guidance, warns about expiration behavior, and sets a boundary on inference. Key guidance is front-loaded before the alternative-tool mention.

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 zero parameters and an output schema available, the description has very little it must cover, yet it still provides the critical distinction from get_loyalty_accounts, expiration-handling guidance, and a limitation warning. The tool is fully specified for an agent to select and invoke correctly.

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 input schema has zero parameters, so there is no parameter burden to clarify. The description nonetheless clarifies what the tool does not need and emphasizes the conceptual distinction from points balances, which is useful for the agent.

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 names a specific resource ('free night certificates') and explains exactly what those are with concrete examples across loyalty programs. It also distinguishes them from points balances, which prevents confusion with a sibling tool.

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 says 'use this rather than get_loyalty_accounts whenever the user asks about certificates, free nights, or award nights' and provides example queries. It also states a clear non-use: the tool does not evaluate property-level certificate coverage.

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