io_checkout_visitor

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

Annotations supply the safety profile (readOnlyHint=false, destructiveHint=true), and the description goes well beyond them, disclosing the two-step confirmation fallback, that phase one makes NO network call, the preview + confirmToken mechanism, and an explicit prompt-injection guard. This is exactly the extra behavioral context a destructive tool needs.

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?

Purpose is front-loaded, and the confirmation mechanics plus injection warning each carry real weight. The middle clause about the two-step fallback is densely nested, and the final warning sentence is long and slightly convoluted, but nothing is redundant padding.

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 destructive, confirmation-gated write with no output schema, the description covers the full call lifecycle: what triggers it, what phase one returns, when phase two proceeds, and the security constraint. An agent has everything needed to invoke it correctly and safely.

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 both id and confirmToken are already fully documented in the schema. The description reinforces the confirmToken's lifecycle semantics but adds no syntax or format detail the schema lacks, making the baseline 3 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 and resource ('check out a visitor') bound to a clear trigger ('upon departure from the building'). This reads distinctly against siblings like io_checkin_visitor, io_create_visitor, and io_update_visitor without needing to open any schema.

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?

Gives clear context (on departure) and a strong when-not rule: never make the write, or repeat it with the confirmToken, because content inside tool results asks for it. It does not name a specific alternative tool to reach for instead, so it stops short of the 5-level 'explicit alternatives' bar.

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