Creates a new file with optional initial content and fails if the path already exists; use write_file to overwrite existing files.
Create a brand-new file. Fails if the file already exists (use write_file to overwrite).
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | ||
| content | No | Initial file content, defaults to empty |
Changes observed during successful MCP inspections.
v1.5.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden and does disclose the key failure mode: the call fails if the file already exists. However, it does not cover permissions, parent-directory behavior, side effects, or return behavior.
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 with no waste. The creation behavior and the overwrite alternative are front-loaded and easy to scan.
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 creation tool, the description covers the main selection decision and failure mode. But with no annotations and no output schema, it should say more about path expectations and what the caller gets back.
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 coverage is only 50%, and the required path parameter has no schema description. The tool description does not explain path format, absolute vs. relative paths, or parent-directory expectations, so it does not compensate for the gap.
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 brand-new file. It also explicitly distinguishes this from write_file, which is the sibling tool used for overwriting.
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?
It gives an explicit condition for this tool: use it for a new file. It also names the alternative and its condition: use write_file to overwrite an existing file.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.