99afff41c6
The first harness changes to move the benchmark off the 1/12 noise floor, on
the model that needs it most (qwen2.5:0.5b: 1/12 -> 4/12, 3/12).
- complete_with_tools now decodes the tool loop at temperature 0 (scoped; chat
keeps default sampling). At Ollama's default 0.8 the weak model sampled away
from the tool-call format into prose/fabrication; the nudge prompt changes
between turns so temp 0 still escapes a failed state on retry.
- Greedy decode made 0.5b's leak deterministic, exposing its real shape: not a
JSON object with a name key, but the name in a <tools> tag and the args in a
SEPARATE object — <tools>write_file</tools>{"path":…} — ~5 of 12 tasks/run.
_NAMED_TAG pairs the tag-name with the following args object, gated on the
known tool set so it still can't fabricate an action.
- Bridge recovers a ```bash block narrated in prose as a run_shell call,
non-destructive only (FENCE_DESTRUCTIVE guard); fires on prose-leak turns,
no-op where the model emits structured calls.
Ablation on 0.5b: structured-JSON-only 0/0 -> fenced+temp0 2/0 -> +split-tag
4/3. The lift is concentrated on the weakest model by design — a 3B emits
proper calls and fails on capability/content (unchanged at 1/12), which no
parser can fix. All recovery paths unit-checked for the positive shapes and
the negatives (prose / unknown tool / destructive block) they must ignore.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>