External feedback (2026-04-30): "Provisioner doesn't read model from
config.yaml and doesn't set MODEL env var. Without MODEL, the adapter
defaults to sonnet and bypasses the mimo routing." Confirmed accurate
for SaaS workspaces.
Trace: claude-code-default/adapter.py reads `runtime_config.model or
"sonnet"` (and hermes reads HERMES_DEFAULT_MODEL via install.sh, which
IS plumbed). For claude-code there's nothing — workspace/config.py
loaded `runtime_config.model` only from YAML, ignoring MODEL_PROVIDER
env. The CP user-data script regenerates /configs/config.yaml at every
boot with only `name`, `runtime`, `a2a` keys (intentionally minimal so
it doesn't carry stale state) — so any user-set runtime_config.model
is wiped on every restart, and the adapter falls back to "sonnet" even
when the user picked Opus in the canvas Config tab.
Fix: when YAML omits runtime_config.model, fall back to the top-level
resolved `model`, which already honors MODEL_PROVIDER env override.
One-line in workspace/config.py. Now MODEL_PROVIDER → top-level model
→ runtime_config.model → adapter sees the user's selection. Sticky
across CP-driven restarts; the canvas Save+Restart loop works as
intended for every runtime, not just hermes.
Tests:
test_runtime_config_model_falls_back_to_top_level — top-level set, runtime_config empty → fallback wins
test_runtime_config_model_yaml_wins_over_top_level — YAML explicit → fallback skipped (precedence)
test_runtime_config_model_picks_up_env_via_top_level — full canvas Save+Restart simulation: env → top-level → runtime_config.model
Negative-control verified: removing the `or model` flips both fallback
tests red with the expected "" vs expected-model mismatch; restoring
flips them green. The yaml-wins test passes either way (correctly,
because precedence is preserved).
Replaces closed PR #2435 — that PR's commit was on a contaminated
branch and accidentally captured unrelated WIP changes (build script
+ a2a_mcp_server refactor) instead of this fix. Self-review caught it
and closed the PR. This branch is clean off main + diff verified
before push.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
0070d0bd59