Mantle - Open-source service runtime configured by agents via WebMCP

Mantle is an open-source service runtime and WebMCP-native Builder that turns business rules into typed schemas, views, procedures, and HTTP/MCP triggers. Design and verify a service in the browser, then hand it to a coding agent to materialize, verify, and deploy to your own Cloudflare account. The OSS, Builder, and first-class Cloudflare deployment path are live now. Mantle Cloud remains in Internal Beta with a waitlist.

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We built Mantle to give people and coding agents a shared, inspectable way to describe a service before turning it into production code. The open-source core models a service with four atoms: Schema, View, Procedure, and Trigger. In the WebMCP-native Builder, an agent can read Mantle's pinned grammar, create or patch a Manifest, seed sandbox data, call projected HTTP/MCP capabilities, and inspect the result in the generated Admin UI. The handoff is for a coder or coding agent to add the product-specific frontend, authentication, integrations, tests, and deployment. The Transaction preset in our launch images demonstrates product, inventory, order, and fulfilment workflows. It does not include payment processing and is not a finished e-commerce product. GPT-6 Astra built the entire mantle.tools homepage and Mantle Cloud SaaS experience. The Mantle core SDK, Admin UI, and Developer UI were initially implemented with GPT-5.6 Sol; Astra then consolidated, optimized, and reviewed that work, including the launch experience. We did not bolt on an artificial Astra runtime dependency: Mantle remains model-agnostic, while this challenge demonstrates Astra working through WebMCP against a real service grammar and executable preview. The OSS and Builder are available today. Mantle Cloud remains in Internal Beta and currently requires joining the waitlist. Feedback on the Manifest model, Builder workflow, and handoff to production code is very welcome.
What became possible in your product with Astra that was not practical before?
Astra made it practical for us to treat a service definition as a live conversation between a human, an agent, and executable infrastructure. It built the mantle.tools homepage and Mantle Cloud SaaS experience, then consolidated, optimized, and reviewed the core SDK, Admin UI, and Developer UI initially implemented with GPT-5.6 Sol. In the WebMCP Builder, an agent can read Mantle's pinned grammar, turn business rules into Schema, View, Procedure, and Trigger manifests, seed and inspect a sandbox, call projected HTTP/MCP capabilities, and leave a concrete handoff for a coder. The result is an inspectable service graph and working interfaces in one session, without adding a challenge-only Astra runtime dependency.