newt-coder — coder plugin closing failure mode T0b.
Background: see the authoritative knowledge card
~/workspaces/knowledge/board/drake/2026-05-29_newt-coder-failure-mode-taxonomy.md.
The default newt worker (newt-flat) sends the operator's task
prompt verbatim with no file contents, then asks the model to emit
a unified diff. Local Ollama coder models reliably invent
plausible-but-wrong context lines under that contract — apply_patch
rejects the patch on context mismatch and the workspace diff stays
empty (failure mode T0b).
newt-coder is the opinionated path: it scans the workspace for
files the task mentions, injects them verbatim into the user
message, and asks the model to emit each updated file in full
(no fences, no prose, no diffs). The reply is parsed by
normalize_emission and the changes are written to the workspace;
the caller then captures a real diff via git diff.
Activation:
- env:
NEWT_CODER=1, or - per-session ACP param:
{ "coder": true }onnew_session.
Both are checked by newt-acp-worker. The legacy newt-flat path is
the default and remains unchanged.