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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is settled. The description adds real value beyond that by disclosing the returned fields (path, size, saver, timestamp) and the plan-quota side effect of the response, though it says nothing about pagination, result limits, or ordering.

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?

One sentence, front-loaded with the verb and resource, with the returned-field list packed into a parenthetical and the quota detail trailing. No filler and nothing that could be cut without losing information.

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?

With no output schema, the description correctly spends its words on what comes back, which is the main gap it needed to fill for a simple read-only listing tool. It stops short of covering result caps or sort order, which an agent enumerating a large store might want.

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?

There is a single optional parameter, 'prefix', and the schema documents it fully at 100% coverage including an example. The description does not mention folder scoping at all, so the schema does all the work; 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?

States a specific verb (List) and a specific resource (files in your space's file storage), and enumerates what each entry carries plus plan storage usage. It is clearly distinct from kb_file_get/kb_file_put/kb_file_delete by the 'list' verb, though no sibling is named explicitly, keeping it a step below the top score.

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?

Usage is only implied: an agent can infer this is the way to enumerate files versus fetching one by name, but the description never says when to use it, when not to, or which sibling handles retrieval of a single file's contents. No prerequisites or exclusions are given.

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