| name | compute-stub |
| description | Diagnostic in-memory compute backend. Use ONLY when the user explicitly asks to verify that the compute pipeline (Registry → IPC → renderer) is wired correctly without invoking real shells or remote services. Off by default — register via ENABLE_COMPUTE_STUB=1. |
| category | Compute |
| tags | ["compute","diagnostic","stub","qa"] |
| triggers | ["diagnose compute","compute health check","verify pipeline","stub backend","test compute"] |
| license | MIT |
| metadata | {"skill-author":"Research Copilot"} |
Stub Compute (diagnostic)
Stub backend (backend: 'stub', toolPrefix: 'stub') is an in-memory no-op that simulates plan/run/stop without invoking any real subprocess or remote API. Available only when the developer sets ENABLE_COMPUTE_STUB=1.
When to use
- The Compute tab seems broken — want to confirm whether the bug is in registry / IPC / renderer plumbing vs. a backend's internals.
- Validating that a new backend you're writing follows the same lifecycle the stub demonstrates.
- Smoke-testing event flow after refactors to lib/compute/.
Do NOT use for real work — there's no actual computation happening.
Behavior
The stub parses keywords from the command string:
| Command contains | Behavior |
|---|
| (default) | Sleeps 100ms then completes with exit code 0 |
SLOW | Sleeps 5000ms (use to exercise stub_stop) |
FAIL | Sleeps 100ms then exits with code 1 + sets failure.code = COMMAND_FAILED |
Combine freely — e.g. SLOW job that may FAIL waits 5s then fails.
Tool flow
list_compute_backends() — confirm stub is registered.compute_plan({ backend: 'stub', command: 'health check' }) — no approval gate.stub_execute({ plan_id }) — kicks off the timer.stub_wait({ run_id }) — blocks until terminal.stub_stop({ run_id }) — cancels (useful for SLOW runs).
If the stub flow succeeds end-to-end but local_* / modal_* flows don't, the bug is backend-internal (sandbox provider, Modal CLI, etc.), not registry/IPC/renderer plumbing.
Reference for adding a new backend
lib/compute/backends/stub/stub-backend.ts is also the canonical
reference implementation for RFC §19 (Adding a new compute backend).
It demonstrates every ComputeBackend method against the simplest
possible state (a Map + setTimeout), so you can read the whole file
in under 5 minutes and see the contracts in action.
