Claude File Manager MCP

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Append to a file

append_file

Append text to the end of a file, creating the file and any missing parent folders if they do not exist. Use it to add content without rewriting existing data.

Instructions

Appends text to the end of a file, creating it if needed.

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": "append_file"
  }
}

Input Schema

Name	Required	Description
`path`	Yes	File path
`content`	Yes	Text to append
`create_parents`	No	Create missing parent folders

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.3.0Nov 13, 2026

TDQS

A3.6/5.0

Behavior3/5

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

With no annotations, the description carries the full burden and does disclose two real behavioral traits: content goes to the end of the file rather than replacing it, and a missing file is created. It stays silent on other write-behavior details an agent would want, such as encoding, newline handling, atomicity, and failure modes for unwritable paths.

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?

A single short sentence with the core action and its key side effect front-loaded. There is no filler, and nothing could be trimmed without losing information.

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

Completeness4/5

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

For a simple three-parameter file tool with a fully described schema and no output schema, the description covers the essential semantics: it appends, and it creates the file if absent. Only fine-grained write behavior is missing, which is a minor gap for this complexity level.

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

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and all three parameters are documented in-schema, including the create_parents default, so the baseline of 3 applies. The description adds no syntax or meaning beyond the schema and does not mention create_parents at all.

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

Purpose4/5

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

"Appends text to the end of a file, creating it if needed" pairs a specific verb with a specific resource and adds the create-on-missing side effect. It is fully clear on its own, but it never names or contrasts with siblings like write_file or edit_file, so the agent must infer the append-vs-overwrite distinction.

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

Usage Guidelines3/5

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

Usage is only implied by the verb: append rather than overwrite. There is no explicit statement of when to choose this over write_file or edit_file, nor any prerequisite or exclusion, so routing relies on the agent's inference from the tool name.

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