MCP Failure Lab v0.7.0

What's Changed

MCP Failure Lab can now run scenarios against external MCP servers over Streamable HTTP or stdio.

Highlights

• Added the target-client adapter contract and registry.
• Added external scenario execution with --target.
• Added bounded setup, execution, observation, cancellation, and cleanup.
• Added separate scenario assertion and adapter lifecycle diagnostics.
• Added Streamable HTTP session termination and active-request cancellation.
• Added working GitHub and GitLab MCP examples.
• Added MCP Registry badges and updated security guidance.

Example

npx mcp-failure-lab run scenario.json --target target.json

Pull Requests

• MCP Registry badges: #66
• Target-client adapter contract: #67
• Security policy updates: #68
• External MCP target orchestration: #69
• Version 0.7.0: #70

Full changelog: v0.6.0...v0.7.0

MCP Failure Lab v0.6.0

What’s changed

MCP Failure Lab 0.6.0 adds Streamable HTTP support alongside the existing stdio transport.

Streamable HTTP

• Start an HTTP server with mcp-failure-lab serve --transport http.
• Configure the listener with --host, --port, and --path.
• Added host, origin, path, and wildcard-address validation.
• Fixed disconnect so it terminates the active HTTP request without stopping the server.
• Added HTTP integration and end-to-end coverage.
• Updated the documentation with setup and Inspector examples.

Distribution

• Added automated publication to the official MCP Registry.
• Added MCP Registry and Glama metadata.
• Added project branding for package and registry listings.

Included pull requests

• #61 — Add Streamable HTTP support
• #63 — Add Glama metadata
• #64 — Publish releases to the MCP Registry
• #65 — Prepare v0.6.0

Full changelog: v0.5.1...v0.6.0

MCP Failure Lab v0.5.1

What's Changed

• Added official MCP Registry metadata.
• Added automatic version synchronization between package.json and server.json.
• Published mcp-failure-lab@0.5.1 to npm and the official MCP Registry.

Pull Request: #62

Full Changelog: v0.5.0...v0.5.1

MCP Failure Lab v0.5.0

What's Changed

• Simplified the project README in #58.
• Migrated to MCP TypeScript SDK v2 in #59.
• Added explicit support for MCP 2026-07-28.
• Retained 2025-11-25 compatibility coverage.
• Preserved existing fault tools, scenarios, assertions, observers, and reporters.

Full Changelog: v0.4.0...v0.5.0

MCP Failure Lab v0.4.0

What’s new

Scenario result assertions

Scenarios can now validate returned MCP tool results with:

• expect.result.isError
• expect.result.textContains

Text matching is case-sensitive and inspects MCP text content only.

Independent observer verification

Scenarios can now run an optional observe call after the primary tool call to verify post-call state through a separate read path.

Observer outcomes, durations, results, errors, and assertion failures are recorded separately and included in console and JSON reports.

Additional improvements

• Added a built-in deterministic demo command.
• Added end-to-end CLI coverage.
• Added Future AGI integration validation.
• Added trusted npm publishing through GitHub Actions.
• Updated examples and project documentation.

Included pull requests

• Built-in demo command: #42
• End-to-end CLI coverage: #43
• Trusted npm publishing: #44
• MCP scenario result assertions: #46
• Independent observer verification: #47
• v0.4.0 release preparation: #48

Full changelog: v0.3.2...v0.4.0

MCP Failure Lab v0.3.2

What's Changed

Fixed

• Fixed stale MCP server version metadata. serverInfo.version now matches the published package version instead of reporting the old hardcoded version.
• CLI and MCP server version metadata now use package.json as the shared source of truth.
• Added integration coverage to prevent version metadata from drifting in future releases.

Verification

• 44 tests passing
• Published package verified with npx
• npx -y mcp-failure-lab@0.3.2 --version reports 0.3.2

Pull Requests

• fix: report package version in MCP server metadata by @anilloutombam in #38
• chore: release v0.3.2 by @anilloutombam in #39

Full Changelog: v0.3.1...v0.3.2

MCP Failure Lab v0.3.1

This release makes MCP Failure Lab available as an npm CLI and adds JSON-driven scenario execution and structured reporting.

You can now run deterministic failure scenarios directly from the command line, inspect results in console or JSON format, and use exit codes for CI workflows. The release also includes a reproducible terminal demo and fixes the packaged CLI executable so the tool works correctly through npx.

MCP Failure Lab is now published to npm:

npx mcp-failure-lab --help

Users of npm version 0.3.0 should upgrade to 0.3.1 or later because 0.3.0 contains a broken CLI executable.

What's changed

CLI and scenario execution

• Added CLI-driven JSON scenario execution in #30
• Added console and machine-readable JSON scenario reporters in #31
• Added a reproducible terminal demo in #32

npm release

• Prepared the package for npm distribution in #23
• Added npm installation instructions in #25
• Prepared the 0.3.0 package release in #33
• Fixed the packaged CLI executable in #35

Contributor experience

• Added first-time contributor automation in #22
• Fixed the first-interaction workflow configuration in #24

Full Changelog: v0.2.0...v0.3.1

MCP Failure Lab v0.2.0

This release adds the first deterministic fault tools and a code-first scenario runner to MCP Failure Lab.

You can now exercise delayed, hanging, and disconnected MCP tool calls, then assert outcomes, timeout behavior, and duration. This release also strengthens testing, CI, coverage, security, and the contributor workflow.

The project remains under active development and is not yet published to npm.

What’s changed

Fault testing

• Added MCP integration coverage and deterministic fault tools in #5
• Added the scenario runner and timeout assertions in #12

Testing and automation

• Added GitHub Actions verification in #7
• Added a code-coverage baseline in #10
• Added Codecov uploads in #11
• Updated a vulnerable transitive dependency in #18

Contributor experience

• Added contribution guidance in #6 and #8
• Simplified the pull-request template in #13
• Added issue templates in #14
• Added community health and security policies in #19

Full changelog: v0.1.0...v0.2.0

MCP Failure Lab v0.1.0 — Initial MCP Server Milestone

MCP Failure Lab v0.1.0

The first working milestone for MCP Failure Lab, a chaos-engineering and resilience-testing toolkit for Model Context Protocol servers.

Included

• TypeScript command-line application with a serve command
• MCP server communicating over stdio
• Discoverable ping tool with deterministic timestamps
• Separation between server construction and transport execution
• Graceful SIGINT and SIGTERM shutdown
• Unit coverage for ping behavior
• MCP client-server integration coverage
• Reproducible type-checking, testing, formatting, and production builds
• Architecture, usage, testing-strategy, and roadmap documentation

Current scope

This release establishes the project foundation and validates MCP communication end to end. Fault scenarios and injection are planned for future releases.

Requirements

• Node.js 22.19.0 or newer
• npm

Try it

git clone https://github.com/anilloutombam/mcp-failure-lab.git
cd mcp-failure-lab
npm install
npm test
npm --silent run dev -- serve

The package is not yet published to npm.

What’s Changed

• Documented the current and planned architecture in [#1](#1)
• Fixed the architecture diagram and improved the project structure in [#2](#2)
• Simplified Mermaid diagrams for GitHub rendering in [#3](#3)
• Added MCP ping integration coverage in [#4](#4)

Source at this release: [v0.1.0](https://github.com/anilloutombam/mcp-failure-lab/tree/v0.1.0)