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

Annotations already declare non-read-only, open-world, idempotent, non-destructive, so the safety profile is covered. The description adds genuinely new context beyond the annotations: confirming does not finalize the booking because "the rental company may still have to accept it" — a behavioral nuance an agent would otherwise not know.

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?

Front-loaded trigger, then the anti-hallucination rule, then the outcome caveat and a concrete example — each sentence carries a distinct payload. The JSON example is useful but borderline redundant with the schema's 25% coverage.

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 three required parameters, an opaque token, and an output schema that covers return values, the description is adequate on the outcome side. It is not adequate on the input side: the agent is never told that status_token is a prerequisite obtained from create_reservation or get_reservation_status, which is the main failure mode for this tool.

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 only 25% — only `code` is documented — and the embedded example at least shows the shape of reservation_number and status_token. However, the description never explains what status_token is, where it comes from, or that market is optional, so the opaque 16-512 char token remains a gap.

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 action (confirm a reservation) bound to a specific input (the 6-digit code the user received), which separates it from the sibling request_confirmation_code. It describes the trigger more than the effect, but an agent can identify the tool correctly from one read.

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?

"Use when the user gives you the 6-digit code they received for a new reservation" gives an explicit trigger, and "Never guess or invent a code" adds a clear guardrail. It stops short of naming the upstream/downstream siblings (request_confirmation_code, get_reservation_status), so the agent must infer the surrounding flow.

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