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

With no annotations present, the description carries the full behavioral burden. It discloses many important traits: it returns specific fields, never returns guest PII, and refuses wrong or missing tokens without revealing whether a booking exists. This gives the agent strong expectations about privacy and error behavior.

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 compact and each sentence earns its place: purpose, parameter source, return contents, and security behavior. It is front-loaded with the main action and avoids redundant restatement of the tool name or schema.

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?

For a lookup tool with no output schema, the description fully covers behavior, return fields, status values, parameter provenance, and error handling. Nothing essential is missing for an agent to select and invoke it 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?

Schema coverage is 100%, so the schema already documents both parameters thoroughly. The description adds extra value by explaining that both parameters come from create_booking and are embedded in the guest's manage link, including the exact URL shape and how to extract the token from it.

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 opens with a specific verb and resource: 'Look up one existing booking' and names the concrete purpose. It naturally distinguishes itself from siblings like check_availability and create_booking by focusing on retrieving an existing booking.

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 description gives clear context: use this tool when a guest needs to confirm an existing booking, and identifies the required credentials from create_booking or the confirmation email. It does not explicitly enumerate when not to use it or name alternative tools, but the conditions are unmistakable.

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