WASM (Phases 0–4)

Phase 0 adds a build+run loop for solve-pure X07 programs as WASM modules, without introducing a new compiler backend. Phase 1 adds WASI 0.2 components (HTTP + CLI runnable targets) on top of Phase 0. Phase 2 adds a Web UI loop (web-ui build|serve|test) on top of Phase 0/1. Phase 3 adds a full-stack app bundle loop (app build|serve|test) that combines Phase 2 (frontend) and Phase 1 (backend). Phase 4 adds native backend targets so x07 wasm component build --emit http|cli can produce runnable standard-world components without guest adapters and without a compose step.

Phases 0–4 are implemented by the x07-wasm tool (repo: x07-wasm-backend).

Delegation model

The core toolchain delegates WASM commands:

• x07 wasm ... delegates to x07-wasm ... on PATH.
• If x07-wasm is not installed/discoverable, delegated commands exit with code 2.

Install

Install x07-wasm from the x07-wasm-backend repo:

cargo install --locked --git https://github.com/x07lang/x07-wasm-backend.git x07-wasm

Phase 1 also requires additional tools on PATH (checked by x07 wasm doctor):

• wasm-tools
• wit-bindgen
• wac
• wasmtime

Phase 2 (component+ESM builds) also uses:

• node
• jco (component transpile)

Profiles (contracts-as-data)

x07-wasm consumes a pinned profile registry by default:

• arch/wasm/index.x07wasm.json
• arch/wasm/profiles/*.json

Validate these files in CI:

x07 wasm profile validate --json

If you need to bypass the registry (e.g. experimentation), use --profile-file.

Build

x07 wasm build:

• calls x07 build --freestanding --emit-c-header …
• compiles the emitted C to wasm32 via clang
• links a reactor-style module via wasm-ld --no-entry
• emits a wasm artifact manifest and a machine report

Example:

x07 wasm build \
  --project ./x07.json \
  --profile wasm_release \
  --out dist/app.wasm \
  --artifact-out dist/app.wasm.manifest.json \
  --json

Run

x07 wasm run instantiates the module under Wasmtime and calls x07_solve_v2 using the WASM Basic C ABI sret convention.

On failures, it writes a deterministic incident bundle under .x07-wasm/incidents/… containing:

• input.bin
• run.report.json
• wasm.manifest.json (if discoverable next to the wasm path)

Machine discovery

Agents should use:

• x07 wasm --cli-specrows
• x07 wasm cli specrows check

Phase 1: components (WASI 0.2)

Phase 1 introduces a component pipeline:

• WIT registry: arch/wit/index.x07wit.json (vendored, pinned)
• Component profile registry: arch/wasm/component/index.x07wasm.component.json

Validate (offline, no external validators):

x07 wasm wit validate --json
x07 wasm component profile validate --json

Phase 4 native targets (adapterless, no compose):

x07 wasm component build --project examples/http_echo/x07.json --emit http --json
x07 wasm component targets --component target/x07-wasm/component/http.component.wasm --wit wit/deps/wasi/http/0.2.8/proxy.wit --world proxy --json
x07 wasm serve --mode canary --component target/x07-wasm/component/http.component.wasm --request-body @examples/http_echo/tests/fixtures/request_body.bin --json

x07 wasm component build --project examples/solve_pure_echo/x07.json --emit cli --json
x07 wasm component targets --component target/x07-wasm/component/cli.component.wasm --wit wit/deps/wasi/cli/0.2.8/command.wit --world command --json
x07 wasm component run --component target/x07-wasm/component/cli.component.wasm --stdin examples/solve_pure_echo/tests/fixtures/in_hello.bin --stdout-out dist/stdout.bin --json

Legacy compose path (Phase 1 adapters + wac plug):

x07 wasm component build --project examples/http_echo/x07.json --emit solve --json
x07 wasm component build --project examples/solve_pure_echo/x07.json --emit http-adapter --json
x07 wasm component compose --adapter http --solve target/x07-wasm/component/solve.component.wasm --out dist/app.http.component.wasm --json
x07 wasm component targets --component dist/app.http.component.wasm --wit wit/deps/wasi/http/0.2.8/proxy.wit --world proxy --json

Notes:

• component build --emit all builds solve + http + cli (native). Build adapters explicitly via http-adapter|cli-adapter.
• Native HTTP components surface failures via response headers (x-x07-diag-code, optional x-x07-diag-data-b64). Native CLI components surface failures via stderr sentinel lines (x07-diag-code: ...).

Run (legacy composed artifacts):

x07 wasm serve --mode canary --component dist/app.http.component.wasm --request-body @examples/http_echo/tests/fixtures/request_body.bin --json
x07 wasm component run --component dist/app.cli.component.wasm --stdin examples/solve_pure_echo/tests/fixtures/in_hello.bin --stdout-out dist/stdout.bin --json

Phase 2: web-ui (browser host)

Phase 2 adds a browser host loop for X07 reducers that consume x07.web_ui.dispatch@0.1.0 and emit x07.web_ui.frame@0.1.0 as UTF-8 JSON bytes.

The canonical std-web-ui package, browser host assets, and WIT contracts live in the x07-web-ui repo.

Validate contracts + profile registry (offline):

x07 wasm web-ui contracts validate --json
x07 wasm web-ui profile validate --json

Build + serve + test (example from x07-web-ui):

git clone https://github.com/x07lang/x07-web-ui.git
cd x07-web-ui

x07 wasm web-ui build --project examples/web_ui_counter/x07.json --profile web_ui_debug --out-dir dist --json
x07 wasm web-ui serve --dir dist --mode listen --strict-mime --json
x07 wasm web-ui test --dist-dir dist --case examples/web_ui_counter/tests/counter.trace.json --json

Component build (transpiled for the browser via jco transpile):

x07 wasm web-ui build --project examples/web_ui_counter/x07.json --profile web_ui_debug --out-dir dist --format component --json

Phase 3: app bundle (full stack)

Phase 3 introduces an app-bundle registry (arch/app/*) and a single closed loop:

• app profile → app build → app serve → app test → incident → regression

Validate (offline):

x07 wasm app contracts validate --json
x07 wasm app profile validate --json

Build + serve + test (example from x07-wasm-backend):

git clone https://github.com/x07lang/x07-wasm-backend.git
cd x07-wasm-backend

x07 wasm app build --profile app_dev --out-dir dist/app --clean --json
x07 wasm app serve --dir dist/app --mode smoke --strict-mime --json
x07 wasm app test --dir dist/app --trace examples/app_fullstack_hello/tests/trace_0001.json --json