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

The annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered elsewhere. The description adds only the "current directory" scoping detail and says nothing about glob expansion, hidden files, sorting, or error behavior on a bad path.

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 with zero filler; it is efficient rather than verbose. It is arguably too short for the tool's surface area, but that is an under-specification issue captured in other dimensions.

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 is trivial (one optional parameter, an output schema exists, annotations cover safety), so the minimal description is close to sufficient. Still, it omits that arbitrary directories and globs are supported, which the schema reveals only if the agent opens it.

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 coverage is 100% and the single path parameter is documented as "Directory or glob to list. Omit for the current directory." The description adds nothing about the path argument and in fact only mentions the default case, but the schema carries the load, so the baseline 3 applies.

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 uses a specific verb and resource ("Lists files") and states a scope ("the current directory"), so the agent knows exactly what the call returns. It does not distinguish this from nearby siblings such as list_objects, pwd, or cd, which is the only thing keeping it from a 5.

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 when-to-use guidance, no mention of alternatives like list_objects for structure objects or pwd for the working directory, and no exclusions. Usage is only implied by the one-line purpose.

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