Schema Sieve Mcp

io.github.mrfentmenPublished by GitHub account mrfentmenv1.0.0Updated Nov 5, 2026

Local JSON Schema structure inspection and privacy-safe fixture planning. Tools include inspect...

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Overview

AI-generated overview

Local MCP server that inspects JSON Schema files and plans privacy-safe test fixtures from their structure.

What you can do
  • Summarize a schema's types, properties, required fields, constraints, composition and references
  • Generate placeholder fixture paths such as string, integer or date-time markers without copying real data
When to use it
Useful when you are writing tests against a JSON Schema and want a quick structural overview plus a list of paths to fill in, especially when schemas are large or contain nested constraints, unions and arrays.
Requirements
Runs as a local Node.js process installed from the npm package and started via node dist/index.js. It reads only local JSON files, with paths bounded by the SCHEMA_SIEVE_ROOT environment variable, which defaults to the workspace parent when launched from the package. No authentication is declared.
Before you install
It reads local JSON files from the configured root, so point SCHEMA_SIEVE_ROOT at a narrow directory. It is explicitly not a JSON Schema validator or a security scanner, so do not rely on it for validation or sensitive-data detection; examples, defaults, constants and sensitive-looking property names are omitted or marked as omitted.

Installation

In SourceWeft

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

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

schema-sieve-mcp

Schema Sieve is a local MCP tool for understanding JSON Schema files while planning tests. It focuses on the part that usually takes the most time: finding required paths, nested constraints, unions, arrays, and likely sensitive fields before writing fixtures.

Tools

  • inspect_schema: summarize types, properties, required fields, constraints, composition, and references.
  • plan_fixture: produce placeholder paths such as <string>, <integer>, and <string:date-time> without inventing or copying test data.

Safety

  • Only local JSON files are accepted.
  • Paths are bounded by SCHEMA_SIEVE_ROOT, which defaults to the workspace parent when launched from the package.
  • Files are capped at 2 MB and results are bounded.
  • Examples, defaults, constants, and sensitive-like property names are omitted or marked as omitted.
  • This is structural guidance, not a JSON Schema validator and not a security scanner.

Run

bash
npm installnpm run buildnode dist/index.js

Source: README.md at commit b2622fc

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v1.0.0LatestSep 22, 2026

Score

40% 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 days25 pts

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  • Auth declared10 pts

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  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

    Declare a license in the repository or the registry entry.