write_file

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

Annotations already mark the tool as destructive and non-read-only; the description adds useful behavior by stating that overwriting an existing file requires confirmation and that the return value is the number of bytes written. This goes beyond the annotations without contradicting them.

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?

The description is compact and front-loaded with the main purpose, followed by a brief Args and Returns breakdown. The Args line is somewhat redundant with the schema, but the overall structure is scannable and not bloated.

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 description covers the essential action and the key destructive-behavior caveat, and the schema/annotations fill in parameter and safety details. It lacks an explicit pointer to edit_file for partial edits and does not clarify how the overwrite-confirmation is surfaced to the agent, making it adequate but not fully complete.

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?

The input schema's nested properties provide descriptions for all relevant parameters, including path, content, append, create_parents, host, and response_format. The description only repeats an abbreviated parameter list and omits response_format, so it contributes little semantic value beyond the schema.

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?

The description clearly states the tool's action: creating, overwriting, or appending to a file, with explicit mention of confirmation when overwriting. This distinguishes it from read, delete, list, and move siblings, though it does not explicitly differentiate it from the edit_file sibling.

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 core use case is implied by the description: use this tool to create, overwrite, or append to a file. However, there is no explicit when-not-to-use guidance or mention of alternatives like edit_file for partial modifications, so the usage guidance remains somewhat implicit.

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