files_write_file

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

With no annotations at all, the description carries the full behavioral burden. It does disclose two useful traits: encoding (UTF-8) and side effect of creating missing parent folders. It does not disclose that the default path truncates an existing file, nor any permission or failure behavior, which are significant omissions for a destructive-capable write.

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 short sentences, the core action front-loaded and the secondary side effect second. Nothing is padded or redundant.

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?

An output schema exists, so return values need not be explained, and the sandbox/encoding/parent-folder facts are covered. However, for a write tool that can destroy existing file content, the missing overwrite-versus-append semantics leave a real gap an agent needs closed before calling it confidently.

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 compensate for all three bare parameters. It only loosely covers them: "in the sandbox" hints at path scope, "UTF-8 text" hints at content encoding, and "write/append" gestures at the append flag — but the critical default (append=false meaning overwrite/truncate) is never stated.

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?

"Write/append UTF-8 text to a file" gives a specific verb and resource, and "in the sandbox" scopes it so an agent can tell it apart from files_read_file or files_delete_file. It does not explicitly name a sibling it is not, but the name plus verb make the intent unambiguous.

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 prerequisite conditions, and no mention of the alternative modes implied by the append flag. An agent must infer from the single word "append" that the same tool overwrites by default, and nothing tells it when overwriting is the right choice versus reading and rewriting.

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