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wasmCloud v2 RC5: wash new, the Wasm Component Model & Agentic AI

The December 17, 2025 wasmCloud community call is a short, focused look at wasmCloud v2 Release Candidate 5 and the developer experience for building Wasm component model projects. Eric Gregory walks through how wash new has been refactored — the old interactive templating wizard is gone, replaced by cloning an example repo directly from a Git URL — and demos the updated Rust hello world that now uses the wstd standard library for Wasm components. Liam Randall closes with the news that the Linux Foundation has launched an Agentic AI Foundation, with Anthropic donating the Model Context Protocol (MCP).

Key Takeaways​

  • wash new no longer ships a templating wizard. To reduce the scope of the wash v2.0 MVP, the interactive language picker was removed in RC5; wash new now clones an example repository from a Git URL to use as a project starting point.
  • The new wash new syntax takes a Git repository URL, an optional --git-ref flag (branch, tag, or commit), a --name flag for the project name and local directory, and a subfolder argument to point at a specific example.
  • Consistency is the theme of RC5. Lucas and Bailey did extensive work refining flags and arguments so a term means what you'd expect, with the command reference docs updated to match.
  • The Rust hello world now uses the wstd standard library for Wasm components, aligning wasmCloud examples with the broader ecosystem rather than carrying a bespoke setup.
  • wasmcloud.toml is in flux for v2. The v1-style wasmcloud.toml is gone for now; configuration currently lives in a config.json under the .wash directory and is being revamped, with multiple formats planned.
  • The Linux Foundation launched an Agentic AI Foundation (AAIF) hosting three projects: MCP (donated by Anthropic), Goose (Block's LLM front end and platform), and the agents.md standard.
  • Sandboxing MCP components is a natural fit for wasmCloud, addressing the non-deterministic I/O of LLMs and risks like prompt injection, remote code execution, lateral movement, and data exfiltration.
  • Next week's meeting (Christmas Eve) is canceled; the community will reconvene in the new year to roll into 2026 and continued RC testing.

Chapters​

Meeting Notes​

wasmCloud v2 RC5 and the wash new Refactor​

The community is in the middle of testing Release Candidate 5 for CNCF wasmCloud, which brings new features, new documentation, and a wave of internal consistency changes. As Eric Gregory explained, Lucas Fontes and Bailey Hayes have been refining how flags and arguments are used across the CLI so that a given term means what a user would reasonably expect, and the command reference docs have been updated to match.

The change most likely to trip up existing users is the way wash new works. As captured in a PR comment from Bailey, the templating feature has been removed for the wash v2.0 MVP until it can be implemented and tested thoroughly. In RC5, wash new instead grabs an example repository at a given Git reference and clones it down to serve as a project starting point. Where you might previously have run wash new and stepped through an interactive wizard to pick a language, you now pull a project directly from a repo.

The updated command reference shows the new shape: wash new followed by the Git repository URL to use as a project template, an optional --git-ref flag to select a branch, tag, or commit, and a --name flag to define the project name and local directory.

Demo: Creating a Rust Component with wash new​

Eric ran through the updated Developer Guide flow for a Rust project. The command points at the wash Git repo URL, uses --name hello so the project is created in a hello directory, and targets the examples/http/hello-world subfolder where that example lives. Running it clones the project down, and the resulting directory contains everything you'd expect for an HTTP hello world component.

The notable update inside that example: the Rust hello world now uses the wstd standard library for Wasm components, in an effort to be as ecosystem-aligned and centralized as possible. The example is built around a couple of simple async functions that return a "Hello from wasmCloud" response. Eric then ran wash dev to show the revamped beginning Developer Guide experience, serving the component and returning the greeting.

The Linux Foundation Agentic AI Foundation and MCP​

Liam Randall highlighted that the Linux Foundation announced the creation of a new Agentic AI Foundation (AAIF), which is hosting three new projects. The first is the Model Context Protocol (MCP) itself, now donated to the foundation by Anthropic so the standard has a neutral home. The second is Goose, Block's front end and platform for interfacing with and building solutions around LLMs. The third is the agents.md standard. In the wasmCloud community, founding members of the AAIF include Cosmonic.

Liam tied this back to wasmCloud by pointing to the work on sandboxing MCP components in the ecosystem. Anthropic's accompanying blog post described the rapid growth and adoption of MCP, and Liam recommended the Sandbox MCP project for examples and walkthroughs of building MCP servers. The reason the fit is so strong: the non-deterministic I/O of LLMs creates a whole class of problems — prompt injection, remote code execution, lateral movement, and ultimately data exfiltration — that a deny-by-default Wasm sandbox is well suited to contain.

Q&A: wasmcloud.toml, Committers, and the Holiday Break​

Aditya asked in chat whether wasmcloud.toml has been retconned, or whether its settings would now live in cargo.toml. Eric explained that in wash v1 a template would typically include a wasmcloud.toml file holding project configuration, but in v2.0 configuration is being revamped. At the moment there is no v1-style wasmcloud.toml; instead, the .wash subdirectory holds a config.json — and even that will change significantly, with multiple configuration formats planned. The team committed to presenting the config revamp to the community in the coming weeks.

Liam closed by thanking the community committers driving the RC series forward, calling out contributors who have been landing commits (including one community member with five recent commits) and the team at Betty Blocks. He then announced that next week's meeting falls on Christmas Eve and is canceled — the community will pick back up in the new year heading into 2026.

WebAssembly News and Updates​

The headline beyond wasmCloud this week is the formation of the Agentic AI Foundation under the Linux Foundation, with Anthropic donating the Model Context Protocol alongside Block's Goose and the agents.md standard. For the WebAssembly ecosystem specifically, the most relevant thread is the wasmCloud examples moving to the wstd standard library for Wasm components — a sign of the Rust component toolchain consolidating around shared, Bytecode Alliance ecosystem libraries rather than per-project glue. wasmCloud v2 RC5 itself is the news to track: as the release candidates harden, the wash CLI, the Developer Guide, and the configuration story are all stabilizing toward a v2.0 release.

What is wasmCloud?​

wasmCloud is a CNCF project that lets you build applications using WebAssembly components and deploy them anywhere — cloud, edge, or Kubernetes clusters. It uses the WebAssembly component model to let you write business logic in any supported language (Rust, Go, Python, TypeScript, C#, and more) while the platform handles capabilities like HTTP, messaging, and key-value storage through a pluggable provider architecture. wasmCloud's reference host is built on Wasmtime, and the wash CLI gives developers a single tool for scaffolding, building, and iterating on components locally with wash dev. With built-in OpenTelemetry observability and Kubernetes integration, wasmCloud bridges WebAssembly's portable, sandboxed execution model and production cloud-native infrastructure.

Topic Deep Dive: Building Wasm Component Model Projects with wash new​

This call is, at its core, about the developer's first five minutes with the Wasm component model. The RC5 refactor of wash new reframes how those first minutes go: instead of an opinionated wizard generating a project, the tool clones a real, working component example from a Git repository, so what you start from is exactly what the maintainers ship and test. That shift matters for the component model specifically, because component projects depend on a coordinated set of moving parts — a WIT world, the language bindings generated from it, and the build toolchain that compiles to a component binary. Pinning all of that to a versioned example repo (selectable by --git-ref) keeps the starting point coherent as the spec and tooling evolve.

The move to the wstd standard library in the Rust hello world reinforces the same idea: rather than wasmCloud carrying a bespoke async runtime shim, the example uses an ecosystem-shared library for writing Wasm components, so what a developer learns in a wasmCloud example transfers directly to other component model projects. Combined with wash dev for an inner-loop that builds and serves the component on save, RC5 is sanding down the on-ramp for building components in Rust and, increasingly, every other language targeting the component model. For a deeper grounding in the underlying spec, the component model documentation is the place to start.

Who Should Watch This​

This call is especially useful for Rust and component developers evaluating wasmCloud v2 — the wash new and wash dev walkthrough starting at 5:37 shows exactly how scaffolding a component changes in RC5. Platform and tooling teams tracking the v2.0 configuration story will want Eric's answer on where wasmcloud.toml went at 12:49. And AI infrastructure builders interested in sandboxing agents and MCP servers should catch Liam's Agentic AI Foundation segment at 10:34.

Up Next​

Next week's community call lands on Christmas Eve and is canceled; the community reconvenes in early January 2026. Watch for continued wasmCloud v2 RC hardening, the promised deep dive on the config revamp and the new configuration formats replacing wasmcloud.toml, and ongoing work on sandboxing MCP components in light of the new Agentic AI Foundation.

Get Involved​

wasmCloud is a CNCF project and contributions are welcome. Join the community:

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