Echo MCP
Echo MCP is a source-available local simulator for external dependencies in AI-assisted end-to-end tests.
Current release: v0.3.0
Workbench status: Released
Built on the Workbench
Echo MCP started as a workbench experiment exploring AI-assisted end-to-end testing.
It has now become the first publicly released project from this line of work.
v0.3.0 adds runtime OpenAPI contract loading while keeping applications on normal REST interfaces.
Status: Released
Version: v0.3.0
Release artifacts stay on GitHub Releases.
Key Ideas
AI decides the test scenario.
Echo MCP can load one local OpenAPI 3.0 JSON contract at runtime through MCP.
Contract-backed validation is partial response validation for supported schema features, not full OpenAPI validation.
Echo MCP executes accepted behavior deterministically.
Applications continue using normal REST interfaces.
- Local-first simulator for external dependencies
- AI-controlled MCP control plane over stdio
- REST HTTP data plane for the application under test
- Deterministic in-memory REST behavior
- REST + MCP separation between control and data planes
- Runtime OpenAPI contract loading through MCP
- Active contract inspection and unloading
- Partial contract-backed response validation
- Validation scope and capability disclosure
- Webhook-style event delivery to configured application endpoints
Downloads
Nagorn.io does not mirror Echo MCP release artifacts.
Use GitHub for source, release notes, checksums, and platform archives.
License
Source-available under Elastic License 2.0.
Not OSI open source.
Commercial and enterprise licensing may be offered separately in the future.
- Source-available (Elastic License 2.0)
- Local-first
- AI-controlled
- Deterministic
- REST + MCP
- Runtime OpenAPI loading
- Partial response validation
- Webhook-style event delivery
Roadmap
No dates are attached here.
- Current: v0.3.0 runtime OpenAPI contract loading released
- Future: Enterprise UI
- Future: Multiple contracts per instance
- Future: HTTPS MCP transport