Backend execution (WS-B)

Capability declaration becomes executable deployment.

Substitution executor

targets/rewrite.py applies a target's declared substitutions to produce a target-ready graph and reports what changed (rewrite_report.py): applied, skipped, unfixable. Two rules ship — IF→beta=0 LIF for norse and AvgPool2d→SumPool2d+Scale for lava_loihi2. An unfixable primitive is named, never dropped, and a post-rewrite drift check quantifies any residual.

Real backends: reference, norse, lava_loihi2

targets/backends.compile_run() is the single entry point. It rewrites, optionally quantizes, gates on the backend's availability, then compiles, runs, and compares the result to the reference interpreter — returning a BackendResult whose status is ok, unavailable, or error. Nothing raises and nothing is faked.

Backend	Extra	Behavior
reference	—	In-process NIR interpreter; always available
norse	norse	Pure-PyTorch simulator; runs when the extra is installed
lava_loihi2	lava	Lava/Loihi 2 path; runs when the SDK is installed

An absent SDK yields status: "unavailable" with a note naming the extra. SDK imports are confined to backends/api.py.

deploy / rewrite / run

spikeforge-verify deploy  --topology conv_net --target reference   # capability view
spikeforge-verify rewrite --topology conv_net --target norse       # substitutions + drift
spikeforge-verify run     --topology conv_net --target reference   # compile + run + compare

The same commands are on spikeforge-targets. deploy exits 0 only when deployable; run exits non-zero unless status == "ok" and the comparison to the reference is within tolerance.

WebSocket + client

A deploy_run action (backend_run reply) adds the executed view beside the existing deployment_report. The BackendRunPanel renders the status, the rewrite report, the drift, and the reference comparison.