feat(ai): split-tag tool-call recovery + greedy decode — 3x lift on 0.5b

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>
This commit is contained in:
leetcrypt
2026-06-10 13:34:21 -07:00
parent 92c0a07d56
commit 99afff41c6
3 changed files with 128 additions and 13 deletions
+43 -13
View File
@@ -71,10 +71,12 @@ class OllamaProvider:
# can't do them (and fall straight to the simple injector).
self._tools_ok: bool | None = None
def _options(self) -> dict:
def _options(self, extra: dict | None = None) -> dict:
opts = {"num_ctx": self.num_ctx, "num_predict": self.num_predict}
if self.num_thread is not None:
opts["num_thread"] = self.num_thread
if extra:
opts.update(extra)
return opts
def _raise_for_status(self, r: requests.Response) -> None:
@@ -133,11 +135,18 @@ class OllamaProvider:
turns); ``system`` is prepended. Returns ``(text, tool_calls)`` where each
call is ``{"name": str, "arguments": dict}``. Raises ``ToolsUnsupported`` if
the model can't do function calling so the bridge can fall back to simple."""
# Greedy decode (temperature 0) for the tool loop: at Ollama's default 0.8 a
# weak model "creatively" narrates the next step in prose or fabricates file
# content instead of emitting a deterministic structured call. The nudge loop
# changes the prompt between turns, so temp 0 still escapes a failing state on
# retry — it just stops sampling away from the correct tool-call format. This
# override is scoped to complete_with_tools; chat (complete/stream) keeps the
# model's default sampling so replies stay natural.
payload = {
"model": self.model,
"stream": False,
"keep_alive": self.keep_alive,
"options": self._options(),
"options": self._options({"temperature": 0.0}),
"tools": tools,
"messages": [{"role": "system", "content": system}] + messages,
}
@@ -188,6 +197,16 @@ class OllamaProvider:
re.I,
)
# The SPLIT-form leak (qwen2.5:0.5b at temp 0, ~half its turns): the tool NAME in
# a `<tools>` tag and the arguments in a SEPARATE bare JSON object with no `name`
# key — `<tools>write_file</tools>{"path":…,"content":…}`. Captures the name; the
# decoder reads the args object that follows from the trailing `{`.
_NAMED_TAG = re.compile(
r"<(tool_call|tool_calls|function_call|function|tools)>\s*"
r"([a-zA-Z_]\w*)\s*</\1>\s*(?=\{)",
re.I,
)
@classmethod
def _coerce_call(cls, obj, valid_names) -> dict | None:
"""Turn a decoded JSON object into a `{"name","arguments"}` call IF it
@@ -225,16 +244,20 @@ class OllamaProvider:
"""Recover tool calls a small/quantized model emitted as TEXT in `content`
instead of the structured `tool_calls` field. Handles qwen's
`<tool_call>{json}</tool_call>` blocks plus the looser CPU-model leaks: bare
JSON, ```json fenced blocks, and alternate wrapper tags (`<tools>`,
`<function_call>`). Scans for every JSON object via a decoder (so nested
braces in arguments parse correctly) and keeps ONLY those that `_coerce_call`
accepts as a known tool — never freeform prose, so it can't fabricate an
action the model didn't structurally request. Returns the text with the
recovered JSON (and now-orphaned wrapper tags / code fences) stripped, plus
the calls."""
JSON, ```json fenced blocks, alternate wrapper tags (`<tools>`,
`<function_call>`), and the SPLIT form where the name sits in a tag and the
args follow as a separate object (`<tools>write_file</tools>{"path":…}`).
Scans for every JSON object via a decoder (so nested braces in arguments parse
correctly) and keeps ONLY those that resolve to a KNOWN tool — never freeform
prose, so it can't fabricate an action the model didn't structurally request.
Returns the text with the recovered JSON (and now-orphaned wrapper tags / code
fences) stripped, plus the calls."""
dec = json.JSONDecoder()
calls: list[dict] = []
spans: list[tuple[int, int]] = []
# Split-form index: the `{` that opens an args object → (tool_name, tag_start),
# so the scan pairs that JSON as arguments and strips the whole tag+object.
split = {m.end(): (m.group(2), m.start()) for m in cls._NAMED_TAG.finditer(text)}
i, n = 0, len(text)
while i < n:
brace = text.find("{", i)
@@ -245,10 +268,17 @@ class OllamaProvider:
except ValueError:
i = brace + 1
continue
call = cls._coerce_call(obj, valid_names)
if call is not None:
calls.append(call)
spans.append((brace, end))
if brace in split:
# `<tag>NAME</tag>{args}` — name from the tag, this object is the args.
name, tag_start = split[brace]
if (not valid_names or name in valid_names) and isinstance(obj, dict):
calls.append({"name": name, "arguments": obj})
spans.append((tag_start, end))
else:
call = cls._coerce_call(obj, valid_names)
if call is not None:
calls.append(call)
spans.append((brace, end))
i = end
if spans:
kept, last = [], 0