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

The annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered; the description earns credit for adding the non-obvious asymmetry that deleted FILES are retained while a deleted FOLDER is permanent. That is exactly the kind of irreversibility detail an agent needs before calling. It stops short of 5 because it does not say whether deleting a folder also removes its contents.

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 sentences, zero filler, with the operation stated first and the recovery/irreversibility caveat immediately after. Every clause carries information the agent cannot get from the schema or annotations.

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 destructive, unannotated-beyond-hints tool with no output schema, the description covers the most important risk (folder deletion is irreversible) but leaves real gaps: the meaning of id and root, and whether folder deletion is recursive. Those omissions matter for a tool that cannot be undone.

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 carry the burden, and it only partially does: "files or folders" clarifies that the files array accepts folder paths, which the schema does not reveal. The id and root parameters are never mentioned, leaving two of three parameters entirely undefined.

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?

"Delete one or more files or folders" gives a specific verb plus the exact resource types and cardinality, so an agent immediately knows this is the destructive removal operation rather than files_move or files_rename. It does not explicitly contrast itself with siblings, which keeps it short of 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?

The description points at files.history / files.restore as the recovery path, which implicitly tells the agent this is the destructive endpoint those two reverse. It never states when to prefer deletion over alternatives or what preconditions exist, so guidance remains implied rather than explicit.

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