device_files

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

With no annotations supplied, the description carries the safety burden well: it discloses atomic replacement, preservation of existing ownership/mode, backup-by-default, and optional compare-and-swap via SHA256 — all non-obvious behaviors that materially change how an agent should write. It stops short of flagging which actions are irreversible/destructive (delete, recursive delete, move) or whether elevated privilege is required, which matters given no destructiveHint.

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?

Three telegraphic sentences, front-loaded with the operation list, then behavior guarantees, then the sibling routing rule. Every clause carries distinct information and there is no filler; the dense fragment style is appropriate for an 11-parameter dispatcher.

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 return shape is covered by the existing output schema, and core write semantics are stated, but for a tool this broad (11 params, mixed read/write/delete actions, zero annotations, zero schema descriptions) the definition leaves too much unresolved — notably max_bytes/recursive/destination semantics and which actions can destroy data. Adequate as a signpost, incomplete as a specification.

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% across 11 parameters, so the description is the only source of parameter meaning, and it does supply the action vocabulary (no enum in schema), plus text-vs-base64 encoding, backup default, and expected_sha256 as a CAS guard. However, several parameters remain entirely unexplained: max_bytes (truncation limit?), recursive, destination, root, and mode's interaction with 'preserve existing ownership/mode'. It compensates partially, not fully.

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?

Opens with a specific noun phrase ('Root file manager') and enumerates the concrete operations (list/stat/read/write/append/hash/mkdir/chmod/copy/move/delete), so an agent knows exactly which file operations live here rather than elsewhere. It also names the boundary against the sibling 'file_transfer_root' for large files/trees, which no other sibling would supply.

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?

Provides one explicit routing rule with its condition: 'Use transfer for large files/trees', which maps onto the sibling file_transfer_root. What is missing is guidance on prerequisites (e.g. that this is a root/privileged surface) and when to prefer other siblings such as app_data_archive or inspect_app_data for app-scoped paths.

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