oasdiff

io.github.oasdiffPublished by GitHub account oasdiffv1.0.0Updated Oct 25, 2026

Detect breaking changes, generate changelogs, diff, and validate OpenAPI specs.

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Overview

AI-generated overview

A remote MCP server that lets an assistant validate OpenAPI specs and compare two versions for breaking changes, changelogs, and structural diffs.

What you can do
Validate a single OpenAPI spec against OpenAPI and JSON Schema rules and return findings, empty when valid. Compare a base and revision spec to detect breaking and warning-level changes that affect existing clients. Produce a full changelog of every detected change down to informational level. Show the raw structural diff of what was added, removed, or modified between two specs. Specs are passed as YAML or JSON.
When to use it
Useful when reviewing an API change before release to see whether it breaks existing clients, when you need a complete changelog between two spec versions, or when checking that a single OpenAPI document is well-formed.
Requirements
Remote streamable HTTP endpoint at api.oasdiff.com; no authentication, environment variables, or headers declared. Specs are supplied as YAML or JSON in the tool calls, so network access to the endpoint is needed.
Before you install
The specs you pass are sent to a third-party remote service, so avoid including confidential API definitions or secrets embedded in them. The tools only analyze and report; they do not modify your specs.

Installation

In SourceWeft

  1. Open oasdiff 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.oasdiff%2Foasdiff/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": {
    "oasdiff": {
      "type": "http",
      "url": "https://api.oasdiff.com/mcp"
    }
  }
}

Tools

4

oasdiff_breaking_changes

Detect breaking API changes between two OpenAPI specifications. Pass the base (old) and revision (new) specs as YAML or JSON; returns the breaking and warning-level changes. Use this when the question is whether an API change breaks existing clients. Use oasdiff_changelog instead to list every change including non-breaking and informational ones, oasdiff_diff for the raw added/removed/modified structure, or oasdiff_validate to check a single spec rather than compare two. Both specs must be valid, self-contained OpenAPI (external $ref URLs or files are not resolved).

Parametersbaserequiredrevisionrequired

oasdiff_changelog

Produce a full changelog of every detected change between two OpenAPI specifications (base vs revision), down to informational changes. Pass both specs as YAML or JSON. Use this when you want the complete set of changes at every severity. Use oasdiff_breaking_changes instead when you only care whether the change is breaking (less noise), or oasdiff_diff for the raw structural diff without a backward-compatibility judgment. Both specs must be valid, self-contained OpenAPI (external $ref URLs or files are not resolved).

Parametersbaserequiredrevisionrequired

oasdiff_diff

Show the structural diff between two OpenAPI specifications (base vs revision): what was added, removed, or modified. Pass both specs as YAML or JSON. Use this when you want the raw structural changes rather than a backward-compatibility verdict. Use oasdiff_breaking_changes to judge whether changes break clients, or oasdiff_changelog for a severity-classified changelog. Both specs must be valid, self-contained OpenAPI (external $ref URLs or files are not resolved).

Parametersbaserequiredrevisionrequired

oasdiff_validate

Validate a single OpenAPI specification against the OpenAPI and JSON Schema rules. Pass the spec as YAML or JSON; returns the findings (empty when the spec is valid). Use this when you have one spec and want to check it is well-formed. For comparing two specs, use oasdiff_breaking_changes, oasdiff_changelog, or oasdiff_diff instead. The spec must be self-contained (external $ref URLs or files are not resolved).

Parametersspecrequired

Version history

1
  1. v1.0.0LatestSep 16, 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.