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Corvid Docs

WASM target

What ships

Corvid compiles to WebAssembly via corvid build --target=wasm. The WASM binary uses a bare (ptr, len) UTF-8 ABI for strings, multi-value returns for struct returns, and a uniform kind discriminator for manifest entries. The runtime ships a real free-list-with-coalescing allocator (no leaky bump allocator).

What works in WASM

  • Pure agents and prompts (with the LLM call routed through the host).
  • Struct returns from prompts (per-struct codegen-emitted decoders).
  • Grounded values (provenance metadata serialized through the bridge).
  • Effect rows and approve tokens (compile-time, no runtime cost).

What doesn’t work in WASM

  • Direct filesystem access (host must mediate).
  • Direct database access (host must mediate; use a connector abstraction).
  • Long-running loops without browser tab activity (browser engines may suspend WASM modules).

The deep doc

docs/internals/wasm-abi.md is the spec; Phase 20n-B and Phase 20n-C closing audits document the ABI history.

In the playground

The website’s WASM playground (slice 33J5) embeds the same WASM target. Code typed in the browser compiles in the browser; the typecheck errors you’d see locally show up the same way in the playground.