postiz-mcp

postiz_upload_file

Upload an image or video file to Postiz storage, receiving an identifier and path to attach to social media posts.

Instructions

Upload a media file (image, video) to Postiz storage via POST /api/uploads/file. Returns { id, path } that you can pass into postiz_create_post value[].image[]. Requires enableWrite.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "postiz_upload_file"
  }
}

Input Schema

Name	Required	Description
`filePath`	No	Absolute path to a local file.
`base64`	No	Base64-encoded contents.
`fileName`	No	File name for multipart upload.
`mimeType`	No	Content-Type.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Apr 30, 2026

TDQS

A3.6/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full disclosure burden. It mentions that the tool requires 'enableWrite' and returns an object with id and path. However, it does not disclose potential side effects, rate limits, file size constraints, or destructive behavior. The description adds some behavioral context but not comprehensive.

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 extremely concise: two sentences that express the main action, return value, and integration with another tool. Every sentence adds unique value without redundancy. It is front-loaded with the primary purpose.

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?

Given the tool's simplicity (4 parameters, no output schema, no annotations), the description covers the essential purpose, return format, and workflow integration. It lacks details on parameter combinations or error handling, but the ties to postiz_create_post provide useful context. It is fairly complete for a straightforward upload tool.

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%, so all four parameters (filePath, base64, fileName, mimeType) have descriptions in the schema. The tool description does not add any additional meaning or usage context for the parameters beyond what the schema provides, meeting the baseline score of 3.

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 action: 'Upload a media file (image, video) to Postiz storage'. It specifies the HTTP method and endpoint, and explains the return value and how to use it with postiz_create_post. This effectively distinguishes it from sibling tools like postiz_upload_from_url by focusing on file/Base64 upload versus URL upload.

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

Usage Guidelines2/5

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

The description does not provide explicit guidance on when to use this tool versus alternatives like postiz_upload_from_url. It mentions a prerequisite ('Requires enableWrite') but lacks context on when this tool is preferred or when to avoid it. No exclusion criteria or alternative references are given.

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