MCP Web Fetch Server

write_file

DestructiveIdempotent

Write text content to a local file, with optional overwrite confirmation to prevent accidental data loss.

Instructions

Write text content to a file within an allowed local directory. If the file already exists and overwrite=false, the user will be asked to confirm before it is replaced.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "path": "<path>",
      "content": "<content>"
    },
    "name": "write_file"
  }
}

Input Schema

Name	Required	Description	Default
`path`	Yes
`content`	Yes
`overwrite`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 14, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already indicate destructive and idempotent behavior. The description adds that if overwrite=false and the file exists, the user will be asked to confirm, which is useful context beyond the annotation flags.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the core purpose, no wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the basic operation and overwrite behavior, but lacks details on path format, content encoding, or error handling. Since an output schema exists, return values are not required, but more context on input constraints would be helpful.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

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 but only explains the overwrite parameter behavior. Path and content parameters lack any description of format, constraints, or examples.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool writes text content to a file within an allowed local directory, using a specific verb and resource. This distinguishes it from siblings like read_file and list_dir.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains when overwrite=false triggers user confirmation, but does not explicitly state when to use this tool versus alternatives like batch_fetch (which fetches from URLs). However, the context of writing local files is clear enough.

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

Deploy Server