Preview file operation

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

The description explicitly says it 'changes nothing on disk', which matches the readOnlyHint=true annotation and adds user-facing assurance. It also discloses the exact checks performed: file existence and size. This adds meaningful behavioral context beyond the annotations, though it does not discuss error behavior or edge cases.

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 efficient, front-loaded sentences. The core behavior, safety guarantee, and usage pattern are all stated without fluff. Every clause 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?

The tool has annotations and an output schema, so the description does not need to explain return values or safety details. However, the missing 'dst' semantics and lack of explicit action values leave the description incomplete for correct invocation, especially for move operations.

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 0%, so the description must compensate. It partially clarifies 'action' (delete/move) and 'src' (the file to check), but it never explains the 'dst' parameter, when it is required, or how it behaves for move versus delete. This is a significant gap for a 3-parameter tool.

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 clearly states a specific operation: 'Preview of a SINGLE delete/move operation' and explains what it does ('checks whether the file exists and how big it is'). It also distinguishes itself from the sibling files_execute_op by saying this runs 'before execute_op', making its role unambiguous.

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 description gives explicit context: use it with for_each to check multiple files before execute_op. This is clear when-to-use guidance. It does not explicitly state when not to use it or list alternative tools, but the reference to execute_op makes the intended workflow evident.

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