Write File

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

Annotations already mark the tool as destructive and idempotent. The description adds valuable behavioral context by warning that existing files are overwritten without warning, stating that it handles text content with proper encoding, and noting that it only works within allowed directories. No contradiction with annotations exists.

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 sentences with no filler. The main action is front-loaded, followed by a necessary caution and two essential constraints. Every sentence earns its place and the description is easy to parse.

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 simple two-parameter write tool with an output schema and strong annotations, the description covers the critical behaviors: overwriting, caution, text encoding, and directory restrictions. It does not explain how to discover allowed directories or what happens if an intermediate directory is missing, but these are minor gaps given the tool's simplicity.

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 provides only parameter names and types with zero description coverage, so the description must compensate. It adds some meaning: "content" is text content with proper encoding, and "path" must be within allowed directories. However, it does not specify path format, file extension expectations, or encoding details, leaving moderate ambiguity.

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 states a specific verb and resource: create a new file or completely overwrite an existing file with new content. It clearly differentiates itself from siblings like read_file and edit_file by emphasizing complete overwrite rather than partial modification or reading.

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 implies when the tool should be used: for creating files or fully replacing their content. It also provides a caution about overwriting without warning and a constraint about allowed directories. However, it does not explicitly mention alternatives like edit_file for partial modifications or when not to use this tool.

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