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@deepseek-ai/dsh-code-runtime
The code-execution seam: an abstract CodeRuntime service (ctx.codeRuntime) defining WHAT a code runtime does — run one model-written program against a set of host-provided async bindings and report { value, logs, error? } — without saying HOW.
This package is the interface third of the capability (the bash trio is the template — see capability seams): implementations subclass CodeRuntime and register the service; the consumer is the tool registry's Code Mode, which generates the model-facing SDK and bridges tool dispatch — both specified in the Code Mode RFC, whose first implementation is a Node worker-thread backend. The runtime knows nothing about tools or sessions: it is handed named async functions and a program string, and everything tool-shaped stays with the consumer.
Model Experience
| Context surface | What the model sees | Token effect |
|---|---|---|
| None directly | The seam receives a program and host bindings but registers no prompt, schema, or message. Code Mode in dsh-tools exposes the SDK and run_code, then converts CodeRunResult into the outer tool result. |
Zero direct tokens. Program logs, values, and failures affect the conversation only through the Code Mode consumer. |
Service API (ctx.codeRuntime)
| Member | Semantics |
|---|---|
run(request) |
Execute one program against the request's bindings. Resolves with an error FIELD for every program outcome — parse/transform failure, thrown exception, budget expiry, abort, substrate death (CodeRunFailure's orthogonal kind taxonomy); it rejects only for caller misuse of the seam itself (e.g. a run submitted after disposal). The program runs as the body of an async function: top-level await/return work, and the completion value becomes result.value when it survives the serialization boundary. |
language |
Readonly descriptor: the source language run expects ('typescript' is the well-known value). Informational, not gating — a consumer that generates language-specific presentation switches on it and fails loud on a language it cannot present. |
isolation |
Readonly descriptor: the execution substrate ('worker-thread', 'process', 'container'). A label for deployments and diagnostics, not a security claim. |
Semantics every implementation must honor (contract details in the class JSDoc): binding calls bridge to the caller's functions verbatim with structured-cloneable arguments/resolutions; the program is treated as a hostile peer (arbitrary binding names are own properties, malformed traffic never crashes the host); no state survives between runs; disposal terminates in-flight runs AND awaits their exit before completing.
Vocabulary
CodeRunRequest (program, bindings, signal?) carries everything the runtime acts on — defaulting (time budgets, output caps) is the implementation's validated config, never a hidden ?? inside run(). bindings is a list of CodeBindingNamespaces (global + functions), each exposed to the program as one global object of async callables. CodeRunResult reports the completion value?, the ordered logs (CodeLogEntry: console/stdout/stderr source, console level, capped text), and the error? (CodeRunFailure: kind + model-feedable message). See src/types.ts for the full contracts.