# ctx.codeRuntime `CodeRuntime` (abstract seam) — provided by `@deepseek-ai/dsh-code-runtime`. Registers one `ctx.codeRuntime` implementation. Program, budget, abort, and substrate failures resolve in CodeRunResult; only seam misuse rejects. Implementations bridge structured-cloneable bindings while treating programs as hostile peers, isolate runs from one another, and terminate and await in-flight runs during disposal. [Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/code-runtime/code-runtime/src/index.ts#L30) ### ctx.codeRuntime.language ```ts website-api abstract readonly language: string ``` The source language run expects `program` to be written in, as a lowercase identifier. Informational, not gating — a consumer that generates language-specific presentation (typed SDK stubs, usage instructions) switches on it and fails loud on a language it cannot present. Well-known value: `'typescript'`. [Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/code-runtime/code-runtime/src/index.ts#L38) ### ctx.codeRuntime.isolation ```ts website-api abstract readonly isolation: string ``` The execution substrate, as a lowercase identifier. Informational, not gating — a descriptor so deployments and diagnostics can tell backends apart, not a security claim. Well-known values: `'worker-thread'`, `'process'`, `'container'`. [Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/code-runtime/code-runtime/src/index.ts#L46) ### ctx.codeRuntime.run(request) ```ts website-api abstract run(request: CodeRunRequest): Promise ``` Execute one program against the request's bindings and capture what it emitted. See the class doc for the resolution contract (error is a result field; rejection means seam misuse only). - `request` — the program, its bindings, and the abort signal; the request carries everything the runtime acts on, with no hidden defaults. **Returns** the run's outcome: completion value (when transferable), the ordered log capture, and the failure (if any). [Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/code-runtime/code-runtime/src/index.ts#L61)