FixMyJSON

io.github.tonbifunPublished by GitHub account tonbifunv0.4.0Updated Oct 24, 2026

Repair broken LLM JSON and check it against a JSON Schema. Flags cut-off output. Free trial.

VerifiedStreamable HTTPWeb executableDeveloper Tools

Overview

AI-generated overview

Repairs malformed JSON produced by LLMs and validates it against a JSON Schema.

What you can do
FixMyJSON is a remote MCP server that takes broken or truncated JSON, typically generated by a language model, and repairs it into valid JSON. It can also check the result against a JSON Schema and flag output that was cut off. It is offered with a free trial.
When to use it
Useful when an assistant or pipeline receives malformed or incomplete JSON from a model and you need it parsed before continuing. Worth adding if you regularly validate model output against a schema or need to detect truncated responses.
Requirements
A remote streamable HTTP endpoint at no package, account, API key, or environment variable is declared. Network access to that endpoint is required.
Before you install
The JSON you submit is sent to a third-party remote service, so avoid sending sensitive or confidential data. No authentication is declared, so the endpoint is not tied to a verified account. The service is described as a free trial, so availability or limits may change.

Installation

In SourceWeft

  1. Open FixMyJSON in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.tonbifun%2Ffixmyjson/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "fixmyjson": {
      "type": "http",
      "url": "https://fixmyjson-api.onrender.com/mcp"
    }
  }
}

Tools

1

repair_json

Repair malformed JSON produced by an LLM or agent (trailing commas, missing quotes, code fences, chatty text around the JSON, <think> blocks, double-encoded JSON) and check the result against a JSON Schema. Returns the repaired value, what was changed, what could not be fixed (unresolved_errors), and `truncated: true` when the input looks cut off (e.g. by a token limit) so you can retry instead of trusting it. It never invents missing data. Free trial, no signup: 20 calls per client per day, 20000 characters per call.

Parametersdatarequiredschemarequired

Version history

1
  1. v0.4.0LatestOct 15, 2026

Score

83% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts

    Declare a GitHub repository with a README, or serve resource_documentation in the OAuth protected-resource metadata.

  • LicenseNot applicable

    A hosted service is used under its provider's terms, so no license is expected here. This check is left out of the percentage.