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

Annotations already declare destructiveHint=true, so the safety profile is covered. The description adds one useful behavioral fact beyond that — the ticket must already be checked in — but says nothing about idempotency, whether an already-checked-out ticket errors, or regional/auth implications of the 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?

A single front-loaded sentence for purpose plus the endpoint mapping, with zero filler. The effect and the exception cases come before the API path.

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 two-required-parameter state-mutation tool with no output schema, the description covers purpose, precondition and effect, and annotations supply the destructive flag. Only error/edge-case behavior at the boundary (double check-out, unknown ticket) is left unstated.

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 24-char hex patterns and the region enum explanation, so the schema carries the parameter burden. The description adds no parameter-level syntax or format detail, 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 precise verb+resource ("Mark a checked-in ticket as checked out"), names the source state, and gives concrete use cases (undo a mistaken check-in, track re-entry). An agent can distinguish this from the inverse sibling humanitix_check_in_ticket 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?

The parenthetical "e.g. to undo a mistaken check-in or track re-entry" tells the agent when this tool is the right choice rather than check-in. It stops short of explicitly naming the alternative tool or stating a when-not condition, so it is clear context without full routing guidance.

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