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

Annotations declare readOnlyHint=false and openWorldHint=true, but the description adds crucial behavioral context: it never handles payment card data, returns a hosted Stripe URL that expires, and triggers a confirmation email. These details go beyond annotations to clarify side effects and limitations, which is essential for an agent to manage expectations.

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 moderately long but each sentence carries value, from the core purpose to the budget warning. It is front-loaded with the primary action and outcome, and the warnings are placed appropriately. Slightly verbose but justified by the complexity.

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 tool with 12 parameters and a multi-step flow, the description covers the prerequisites, the checkout flow, expiration, email confirmation, and a budget guardrail. It mentions expires_at in the response, and no output schema exists, so the description covers all essential context an agent needs to call 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 description coverage is 100%, so the schema already documents each parameter. The description does not add meaning beyond the schema; it mentions prebook_id format (pbk_xxx) but that is already in the schema. Baseline 3 is appropriate.

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: 'Initiate a booking from a valid quote.' Clearly distinguishes from siblings like prebook_stay (prerequisite) and cancel_booking. It also explains the outcome (returns hosted checkout URL), making its role unambiguous.

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?

Provides an explicit workflow: 'Call get_quote, then prebook_stay to obtain prebook_id and confirm locked terms.' Also gives a when-not-to-use condition: 'If the total exceeds a budget the user stated, do NOT call this yet.' This gives clear, actionable usage guidance and sequencing.

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