things_exists

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

The annotations already cover read-only and idempotent safety. The description adds an important behavioral caveat: 'Automation errors are not reported as absence.' This clarifies how false results should be interpreted, which is valuable context beyond the structured annotations.

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?

Two short sentences with no filler. The primary purpose is front-loaded in the first sentence, and the important error-semantics caveat appears in the second. Every word 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?

For a simple existence-check tool with a rich output schema and strong annotations, the description plus the error caveat is largely adequate. It could be more complete by addressing how this differs from things_get_item, but that gap is more of a usage-guidance issue than a fundamental incompleteness.

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?

The description names the two parameters ('kind and ID') and indicates their role together as the identity criterion. However, schema description coverage is 0%, and the description does not explain the accepted kind enum values or ID constraints beyond what the schema already provides. It provides minimal added semantic value.

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?

The description states a specific operation: 'Check whether an item exists by kind and ID.' This clearly identifies the resource and the predicate nature of the tool. It does not explicitly contrast with sibling things_get_item, so it stops short of full sibling differentiation.

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?

There is no guidance on when to use this tool instead of things_get_item or other item-related siblings. The description implies an existence check but does not explain that it should be used for lightweight verification before actions, nor when get_item would be more appropriate.

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