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

Goes well beyond the annotations by disclosing the permission model on both sides, the side effect that destination sharing may change who can access the file, and a no-overwrite rule. These are exactly the mutation risks an agent needs and are not derivable from destructiveHint/idempotentHint alone.

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?

Purpose is front-loaded in the first sentence and each subsequent sentence adds a distinct constraint with no repetition. The final retry sentence is slightly vague about what an "uncertain result" looks like, which keeps it from being maximally crisp.

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 two-parameter mutation tool with an output schema already covering return values, the description supplies purpose, permissions, side effects, overwrite policy, and retry guidance. Nothing essential for a correct first call is missing.

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 carries the burden for file_hash and target_folder_hash. It clarifies that the target is a folder and must belong to the same owner (a real validity constraint on the parameter), but adds nothing about hash format, sourcing, or error behavior for an invalid hash.

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 and resource ("Move a file between folders") plus a scope constraint ("same owner"), which cleanly separates it from the folder-level sibling filesfm_move_folder. It stops short of naming that sibling explicitly, so the differentiation comes from the resource word rather than an explicit contrast.

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?

Gives concrete preconditions (removal rights at source, addition rights at destination, files:write and account permissions) and a retry rule ("Inspect the destination before retrying an uncertain result"). It does not explicitly state when to prefer this over rename_file or move_folder, but the context for calling it is clear.

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