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

Annotations already declare destructiveHint=true, so the mutation risk is conveyed structurally. The description adds value by disclosing the return content (scanning messages) and the undo path, but says nothing about permissions, duplicate-scan behavior, or rate limits that matter for a door-scanning mutation.

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?

Three short sentences, front-loaded with the action, then return behavior, then the inverse tool and endpoint. No filler; every sentence earns its place.

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?

Low-complexity two-required-param mutation with no output schema, and the description covers the action, the return payload, and the undo route. The remaining gap is behavioral edge cases (duplicate check-ins, failure modes), which is minor for this tool shape.

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%, including the hex-id format guidance and the region enum, so the schema carries parameter meaning. The description adds only the endpoint template, which implies event/ticket ids but offers no syntax or format detail beyond the schema.

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?

Specific verb+resource ('Mark a ticket as checked in at the door') plus the side effect of returning scanning messages. It explicitly names the inverse sibling humanitix_check_out_ticket, so an agent can distinguish it from the check-out tool without opening either 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?

States the context ('at the door') and names the alternative for reversing the action ('Undo with humanitix_check_out_ticket'), which routes the agent correctly. It stops short of broader when-not-to-use guidance (e.g. already-checked-in tickets, duplicate scans), so it is clear context without full exclusions.

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