printful-mcp-server

uploadFile

Upload an image file to Printful for print-on-demand products. Returns a file ID needed to create products.

Instructions

Upload a design file (image) to Printful. Returns file ID to use when creating products.

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": {
      "file_path": "<file_path>"
    },
    "name": "uploadFile"
  }
}

Input Schema

Name	Required	Description	Default
`type`	No	File type: 'default' for print file, 'preview' for mockup preview
`file_path`	Yes	Local filesystem path to the image file

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 2, 2026

TDQS

A3.8/5.0

Behavior3/5

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

No annotations are provided, so the description carries the burden. It discloses that the tool uploads a file and returns a file ID for product creation, which is useful behavioral context. However, it omits details like permissions, file size limits, or side effects (e.g., file persists on Printful). This is a moderate level of transparency.

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?

The description is two sentences, front-loaded with the action, and every word serves a purpose. It is concise and easy to parse without unnecessary detail.

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?

The tool is simple, the schema covers all parameters, and the description explains the return value's purpose despite no output schema. It lacks details on file formats or limits, but given its simplicity, the description is sufficiently complete for an agent to understand its role and invocation.

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% (both file_path and type have descriptions). The description adds no extra parameter semantics beyond mentioning the upload and its return value, so the baseline score of 3 is appropriate.

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?

The description clearly states the action: 'Upload a design file (image) to Printful.' It also mentions the key outcome (returns file ID for creating products). However, it does not explicitly distinguish from the sibling tool uploadFileFromUrl, though the parameter schema clarifies the local file path.

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 implies when to use it: when you have a design file and need a file ID for product creation. It does not explicitly mention alternatives or exclusions, but the context is clear enough for an agent to select this tool over uploadFileFromUrl based on the local path requirement.

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