refactor: dedupe inner-tool model routing into a single helper

src/webwright/config/model_claude.yaml

@@ -6,14 +6,8 @@
 # Required env:
 #   - ANTHROPIC_API_KEY (agent, image_qa, and self_reflection tools)
 
-model: &model
+model:
   model_class: anthropic
   model_name: claude-opus-4-7
   anthropic_endpoint: https://api.anthropic.com/v1/messages
   anthropic_version: "2023-06-01"
-
-tools:
-  image_qa:
-    model: *model
-  self_reflection:
-    model: *model

src/webwright/tools/_model_config.py

@@ -0,0 +1,77 @@
+"""Resolve the model client used by inner tools (image_qa, self_reflection).
+
+The CLI snapshots the fully merged run config to
+``<workspace_dir>/config_snapshot/merged_config.yaml``; the tools read that file
+(or an explicit ``--model-config`` override) and instantiate the same model the
+agent uses.
+"""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from typing import Any
+
+import yaml
+
+from webwright.models import get_model
+
+DEFAULT_MERGED_CONFIG_RELPATH = Path("config_snapshot") / "merged_config.yaml"
+
+
+def _load_structured_config(path: Path) -> dict[str, Any]:
+    text = path.read_text(encoding="utf-8")
+    if path.suffix.lower() in {".yaml", ".yml"}:
+        loaded = yaml.safe_load(text)
+    else:
+        loaded = json.loads(text)
+    if not isinstance(loaded, dict):
+        raise ValueError(f"Model config must be an object: {path}")
+    return loaded
+
+
+def _extract_model_block(config: dict[str, Any]) -> dict[str, Any]:
+    model_block = config.get("model")
+    if not isinstance(model_block, dict):
+        raise ValueError(
+            "Model config is missing a top-level `model:` block; "
+            "stack a model_*.yaml (e.g. model_claude.yaml) or pass --model-config <path>."
+        )
+    return model_block
+
+
+def resolve_model_config_path(model_config_arg: str, *, workspace_dir: str) -> Path:
+    """Return the path to a config containing a top-level ``model:`` block.
+
+    Resolution order:
+      1. ``model_config_arg`` (absolute or relative to ``workspace_dir``).
+      2. ``<workspace_dir>/config_snapshot/merged_config.yaml`` (written by the CLI).
+    """
+    candidates: list[Path] = []
+    if model_config_arg:
+        configured = Path(model_config_arg)
+        candidates.append(configured)
+        if workspace_dir and not configured.is_absolute():
+            candidates.append(Path(workspace_dir) / configured)
+    if workspace_dir:
+        candidates.append(Path(workspace_dir) / DEFAULT_MERGED_CONFIG_RELPATH)
+    for candidate in candidates:
+        if candidate.exists():
+            return candidate.resolve()
+    raise FileNotFoundError(
+        "No tool model config found. Pass --model-config <path> or run via the agent so "
+        f"<workspace-dir>/{DEFAULT_MERGED_CONFIG_RELPATH} is available."
+    )
+
+
+def load_tool_model(
+    *,
+    model_config_arg: str,
+    workspace_dir: str,
+    timeout_seconds: int,
+) -> Any:
+    config_path = resolve_model_config_path(model_config_arg, workspace_dir=workspace_dir)
+    config = _load_structured_config(config_path)
+    model_block = dict(_extract_model_block(config))
+    model_block["request_timeout_seconds"] = timeout_seconds
+    return get_model(model_block)