dsh-fabric-code-runtime-quickjs

QuickJS WASM provider for DSH's existing CodeRuntime service. Every run receives a fresh context, is typechecked against the exact binding names supplied by Code Mode, enforces source-compilation, whole-run wall-time, memory, stack, and output budgets, validates JSON bridge traffic, and drains or aborts host calls during teardown.

QuickJS is a stronger isolation boundary than the default worker thread for JavaScript globals and host module access, but it is not a complete process or operating-system security boundary. Binding functions remain the only host capabilities exposed to guest code. Binding globals are lexical arguments, so every DSH-portable name remains usable and guest mutation cannot replace runtime deadline gates.

Config

The provider row accepts these optional positive-integer budgets:

| Field | Default | Constraint | |---|---:|---| | maxWallMs | 600000 | At most 2147483647, Node's maximum timer delay; includes TypeScript checking, cold WASM initialization, and guest execution. | | maxSourceBytes | 262144 | Caps the program plus generated binding declarations before TypeScript parsing. | | memoryLimitBytes | 536870912 | At most 4294967295, the WASM32 address ceiling. | | maxStackBytes | 262144 | Positive safe integer. | | maxOutputBytes | 67108864 | At least 128; applies to the combined serialized result. |

A full workspace composition test verifies the central path run_code → DSH ToolRuntime sub-dispatch → fabric_mesh → DSH storage and session projection. The provider does not register tools or own orchestration.

The current DSH CodeRunRequest does not carry the detailed generated SDK declaration prelude, so this provider checks namespace/member existence and ordinary TypeScript semantics with generic JSON argument types and permissive result types. DSH ToolRuntime remains the execution and policy authority and supplies the executing agent's run-scoped tools.describe/tools.call bindings like every other CodeRuntime provider.