diff --git a/src/models.py b/src/models.py
index 16bc71c..fe38524 100644
--- a/src/models.py
+++ b/src/models.py
@@ -368,18 +368,70 @@ class Preset:
   )
 
 @dataclass
-class ToolPreset:
+class Tool:
  name: str
- categories: Dict[str, Dict[str, Any]]
+ approval: str = 'auto'
+ weight: int = 3
+ parameter_bias: Dict[str, str] = field(default_factory=dict)
 
  def to_dict(self) -> Dict[str, Any]:
   return {
-   "categories": self.categories,
+   "name": self.name,
+   "approval": self.approval,
+   "weight": self.weight,
+   "parameter_bias": self.parameter_bias,
+  }
+
+ @classmethod
+ def from_dict(cls, data: Dict[str, Any]) -> "Tool":
+  return cls(
+   name=data["name"],
+   approval=data.get("approval", "auto"),
+   weight=data.get("weight", 3),
+   parameter_bias=data.get("parameter_bias", {}),
+  )
+
+@dataclass
+class ToolPreset:
+ name: str
+ categories: Dict[str, List[Union[Tool, Any]]]
+
+ def to_dict(self) -> Dict[str, Any]:
+  serialized_categories = {}
+  for cat, tools in self.categories.items():
+   serialized_categories[cat] = [t.to_dict() if isinstance(t, Tool) else t for t in tools]
+  return {
+   "categories": serialized_categories,
   }
 
  @classmethod
  def from_dict(cls, name: str, data: Dict[str, Any]) -> "ToolPreset":
+  raw_categories = data.get("categories", {})
+  parsed_categories = {}
+  for cat, tools in raw_categories.items():
+   parsed_categories[cat] = [Tool.from_dict(t) if isinstance(t, dict) else t for t in tools]
   return cls(
    name=name,
-   categories=data.get("categories", {}),
+   categories=parsed_categories,
+  )
+
+@dataclass
+class BiasProfile:
+ name: str
+ tool_weights: Dict[str, int] = field(default_factory=dict)
+ category_multipliers: Dict[str, float] = field(default_factory=dict)
+
+ def to_dict(self) -> Dict[str, Any]:
+  return {
+   "name": self.name,
+   "tool_weights": self.tool_weights,
+   "category_multipliers": self.category_multipliers,
+  }
+
+ @classmethod
+ def from_dict(cls, data: Dict[str, Any]) -> "BiasProfile":
+  return cls(
+   name=data["name"],
+   tool_weights=data.get("tool_weights", {}),
+   category_multipliers=data.get("category_multipliers", {}),
   )
diff --git a/src/tool_presets.py b/src/tool_presets.py
index 1f288a2..b3519fb 100644
--- a/src/tool_presets.py
+++ b/src/tool_presets.py
@@ -1,91 +1,110 @@
 import tomllib
 import tomli_w
 from pathlib import Path
-from typing import Dict, List, Optional, Union
+from typing import Dict, List, Optional, Union, Any
 from src import paths
-from src.models import ToolPreset
+from src.models import ToolPreset, BiasProfile
 
 class ToolPresetManager:
  def __init__(self, project_root: Optional[Union[str, Path]] = None):
   self.project_root = Path(project_root) if project_root else None
 
- def _load_from_path(self, path: Path) -> Dict[str, ToolPreset]:
+ def _get_path(self, scope: str) -> Path:
+  if scope == "global":
+   return paths.get_global_tool_presets_path()
+  elif scope == "project":
+   if not self.project_root:
+    raise ValueError("Project root not set for project scope operation.")
+   return paths.get_project_tool_presets_path(self.project_root)
+  else:
+   raise ValueError(f"Invalid scope: {scope}")
+
+ def _read_raw(self, path: Path) -> Dict[str, Any]:
   if not path.exists():
    return {}
   try:
    with open(path, "rb") as f:
-    data = tomllib.load(f)
-   presets = {}
-   for name, config in data.items():
-    if isinstance(config, dict):
-     presets[name] = ToolPreset.from_dict(name, config)
-   return presets
+    return tomllib.load(f)
   except Exception:
    return {}
 
- def load_all(self) -> Dict[str, ToolPreset]:
-  """
-  Merges global and project presets. 
-  Project presets override global ones if they have the same name.
-  """
-  presets = self._load_from_path(paths.get_global_tool_presets_path())
-  if self.project_root:
-   project_presets = self._load_from_path(paths.get_project_tool_presets_path(self.project_root))
-   presets.update(project_presets)
-  return presets
-
- def save_preset(self, preset: ToolPreset, scope: str = "project") -> None:
-  """
-  Saves a preset to either 'global' or 'project' scope.
-  Scope must be 'global' or 'project'.
-  """
-  if scope == "global":
-   path = paths.get_global_tool_presets_path()
-  elif scope == "project":
-   if not self.project_root:
-    raise ValueError("Project root not set for project scope saving.")
-   path = paths.get_project_tool_presets_path(self.project_root)
-  else:
-   raise ValueError(f"Invalid scope: {scope}")
-  
-  data = {}
-  if path.exists():
-   try:
-    with open(path, "rb") as f:
-     data = tomllib.load(f)
-   except Exception:
-    data = {}
-  
-  data[preset.name] = preset.to_dict()
-  
+ def _write_raw(self, path: Path, data: Dict[str, Any]) -> None:
   path.parent.mkdir(parents=True, exist_ok=True)
   with open(path, "wb") as f:
    tomli_w.dump(data, f)
 
+ def load_all_presets(self) -> Dict[str, ToolPreset]:
+  global_path = paths.get_global_tool_presets_path()
+  global_data = self._read_raw(global_path).get("presets", {})
+  
+  presets = {}
+  for name, config in global_data.items():
+   if isinstance(config, dict):
+    presets[name] = ToolPreset.from_dict(name, config)
+  
+  if self.project_root:
+   project_path = paths.get_project_tool_presets_path(self.project_root)
+   project_data = self._read_raw(project_path).get("presets", {})
+   for name, config in project_data.items():
+    if isinstance(config, dict):
+     presets[name] = ToolPreset.from_dict(name, config)
+  
+  return presets
+
+ def load_all(self) -> Dict[str, ToolPreset]:
+  """Backward compatibility for load_all()."""
+  return self.load_all_presets()
+
+ def save_preset(self, preset: ToolPreset, scope: str = "project") -> None:
+  path = self._get_path(scope)
+  data = self._read_raw(path)
+  if "presets" not in data:
+   data["presets"] = {}
+  data["presets"][preset.name] = preset.to_dict()
+  self._write_raw(path, data)
+
  def delete_preset(self, name: str, scope: str = "project") -> None:
-  """
-  Deletes a preset from the specified scope.
-  Scope must be 'global' or 'project'.
-  """
-  if scope == "global":
-   path = paths.get_global_tool_presets_path()
-  elif scope == "project":
-   if not self.project_root:
-    raise ValueError("Project root not set for project scope deletion.")
-   path = paths.get_project_tool_presets_path(self.project_root)
-  else:
-   raise ValueError(f"Invalid scope: {scope}")
+  path = self._get_path(scope)
+  data = self._read_raw(path)
+  if "presets" in data and name in data["presets"]:
+   del data["presets"][name]
+   self._write_raw(path, data)
+
+ def load_all_bias_profiles(self) -> Dict[str, BiasProfile]:
+  global_path = paths.get_global_tool_presets_path()
+  global_data = self._read_raw(global_path).get("bias_profiles", {})
   
-  if not path.exists():
-   return
+  profiles = {}
+  for name, config in global_data.items():
+   if isinstance(config, dict):
+    cfg = dict(config)
+    if "name" not in cfg:
+     cfg["name"] = name
+    profiles[name] = BiasProfile.from_dict(cfg)
   
-  try:
-   with open(path, "rb") as f:
-    data = tomllib.load(f)
-  except Exception:
-   return
+  if self.project_root:
+   project_path = paths.get_project_tool_presets_path(self.project_root)
+   project_data = self._read_raw(project_path).get("bias_profiles", {})
+   for name, config in project_data.items():
+    if isinstance(config, dict):
+     cfg = dict(config)
+     if "name" not in cfg:
+      cfg["name"] = name
+     profiles[name] = BiasProfile.from_dict(cfg)
   
-  if name in data:
-   del data[name]
-   with open(path, "wb") as f:
-    tomli_w.dump(data, f)
+  return profiles
+
+ def save_bias_profile(self, profile: BiasProfile, scope: str = "project") -> None:
+  path = self._get_path(scope)
+  data = self._read_raw(path)
+  if "bias_profiles" not in data:
+   data["bias_profiles"] = {}
+  data["bias_profiles"][profile.name] = profile.to_dict()
+  self._write_raw(path, data)
+
+ def delete_bias_profile(self, name: str, scope: str = "project") -> None:
+  path = self._get_path(scope)
+  data = self._read_raw(path)
+  if "bias_profiles" in data and name in data["bias_profiles"]:
+   del data["bias_profiles"][name]
+   self._write_raw(path, data)
diff --git a/tests/test_bias_models.py b/tests/test_bias_models.py
new file mode 100644
index 0000000..e7e547f
--- /dev/null
+++ b/tests/test_bias_models.py
@@ -0,0 +1,46 @@
+import pytest
+from src.models import Tool, ToolPreset, BiasProfile
+
+def test_tool_model():
+ tool = Tool(name="read_file", weight=5, parameter_bias={"path": "preferred"})
+ data = tool.to_dict()
+ assert data["name"] == "read_file"
+ assert data["weight"] == 5
+ assert data["parameter_bias"]["path"] == "preferred"
+ 
+ tool2 = Tool.from_dict(data)
+ assert tool2.name == "read_file"
+ assert tool2.weight == 5
+ assert tool2.parameter_bias["path"] == "preferred"
+
+def test_tool_preset_extension():
+ # Verify that ToolPreset correctly parses and serializes Tool objects
+ tool_data = {"name": "read_file", "weight": 4, "parameter_bias": {"path": "high"}}
+ raw_data = {"categories": {"General": [tool_data]}}
+ 
+ # Test parsing via from_dict
+ preset = ToolPreset.from_dict("test", raw_data)
+ assert isinstance(preset.categories["General"][0], Tool)
+ assert preset.categories["General"][0].weight == 4
+ 
+ # Test serialization
+ data = preset.to_dict()
+ assert data["categories"]["General"][0]["weight"] == 4
+ assert data["categories"]["General"][0]["name"] == "read_file"
+
+def test_bias_profile_model():
+ profile = BiasProfile(
+  name="Execution-Focused",
+  tool_weights={"run_powershell": 5},
+  category_multipliers={"Surgical": 1.5}
+ )
+ data = profile.to_dict()
+ assert data["tool_weights"]["run_powershell"] == 5
+ assert data["category_multipliers"]["Surgical"] == 1.5
+ 
+ # BiasProfile.from_dict expects 'name' inside the dict as well if coming from load_all_bias_profiles
+ data["name"] = "Execution-Focused"
+ profile2 = BiasProfile.from_dict(data)
+ assert profile2.name == "Execution-Focused"
+ assert profile2.tool_weights["run_powershell"] == 5
+ assert profile2.category_multipliers["Surgical"] == 1.5
diff --git a/tests/test_tool_preset_manager.py b/tests/test_tool_preset_manager.py
index 6d376c5..b1e3826 100644
--- a/tests/test_tool_preset_manager.py
+++ b/tests/test_tool_preset_manager.py
@@ -2,7 +2,7 @@ import pytest
 import tomli_w
 from pathlib import Path
 from src.tool_presets import ToolPresetManager
-from src.models import ToolPreset
+from src.models import ToolPreset, BiasProfile, Tool
 from src import paths
 
 @pytest.fixture
@@ -25,17 +25,18 @@ def temp_paths(tmp_path, monkeypatch):
   "project_presets": project_presets
  }
 
-def test_load_all_merged(temp_paths):
+def test_load_all_presets_merged(temp_paths):
  # Setup global presets
  global_data = {
-  "default": {
-   "categories": {
-    "file": {"read": True},
-    "shell": {"run": False}
+  "presets": {
+   "default": {
+    "categories": {
+     "General": [{"name": "read_file", "approval": "auto"}]
+    }
+   },
+   "global_only": {
+    "categories": {"Web": [{"name": "web_search", "approval": "ask"}]}
    }
-  },
-  "global_only": {
-   "categories": {"web": {"search": True}}
   }
  }
  with open(temp_paths["global_presets"], "wb") as f:
@@ -43,98 +44,78 @@ def test_load_all_merged(temp_paths):
   
  # Setup project presets (overrides 'default')
  project_data = {
-  "default": {
-   "categories": {
-    "file": {"read": True},
-    "shell": {"run": True} # Override
+  "presets": {
+   "default": {
+    "categories": {
+     "General": [{"name": "read_file", "approval": "auto", "weight": 5}]
+    }
    }
-  },
-  "project_only": {
-   "categories": {"git": {"commit": True}}
   }
  }
  with open(temp_paths["project_presets"], "wb") as f:
   tomli_w.dump(project_data, f)
   
  manager = ToolPresetManager(project_root=temp_paths["project_dir"])
- all_presets = manager.load_all()
+ all_presets = manager.load_all_presets()
  
  assert "default" in all_presets
- assert all_presets["default"].categories["shell"]["run"] is True # Overridden
+ assert isinstance(all_presets["default"].categories["General"][0], Tool)
+ assert all_presets["default"].categories["General"][0].weight == 5
  assert "global_only" in all_presets
- assert "project_only" in all_presets
- assert all_presets["global_only"].categories["web"]["search"] is True
- assert all_presets["project_only"].categories["git"]["commit"] is True
 
-def test_save_preset_global(temp_paths):
- manager = ToolPresetManager()
- preset = ToolPreset(name="new_global", categories={"test": {"ok": True}})
- 
- manager.save_preset(preset, scope="global")
- 
- assert temp_paths["global_presets"].exists()
- loaded = manager._load_from_path(temp_paths["global_presets"])
- assert "new_global" in loaded
- assert loaded["new_global"].categories == {"test": {"ok": True}}
-
-def test_save_preset_project(temp_paths):
- manager = ToolPresetManager(project_root=temp_paths["project_dir"])
- preset = ToolPreset(name="new_project", categories={"test": {"ok": False}})
- 
- manager.save_preset(preset, scope="project")
- 
- assert temp_paths["project_presets"].exists()
- loaded = manager._load_from_path(temp_paths["project_presets"])
- assert "new_project" in loaded
- assert loaded["new_project"].categories == {"test": {"ok": False}}
-
-def test_delete_preset_global(temp_paths):
- # Initial global setup
+def test_bias_profiles_merged(temp_paths):
+ # Setup global biases
  global_data = {
-  "to_delete": {"categories": {}},
-  "keep": {"categories": {}}
+  "bias_profiles": {
+   "Discovery": {
+    "tool_weights": {"web_search": 5},
+    "category_multipliers": {"Web": 1.5}
+   }
+  }
  }
  with open(temp_paths["global_presets"], "wb") as f:
   tomli_w.dump(global_data, f)
   
- manager = ToolPresetManager()
- manager.delete_preset("to_delete", scope="global")
- 
- loaded = manager._load_from_path(temp_paths["global_presets"])
- assert "to_delete" not in loaded
- assert "keep" in loaded
-
-def test_delete_preset_project(temp_paths):
- # Initial project setup
+ # Setup project biases
  project_data = {
-  "to_delete": {"categories": {}},
-  "keep": {"categories": {}}
+  "bias_profiles": {
+   "Execution": {
+    "tool_weights": {"run_powershell": 5}
+   }
+  }
  }
  with open(temp_paths["project_presets"], "wb") as f:
   tomli_w.dump(project_data, f)
   
  manager = ToolPresetManager(project_root=temp_paths["project_dir"])
- manager.delete_preset("to_delete", scope="project")
+ profiles = manager.load_all_bias_profiles()
  
- loaded = manager._load_from_path(temp_paths["project_presets"])
- assert "to_delete" not in loaded
- assert "keep" in loaded
+ assert "Discovery" in profiles
+ assert profiles["Discovery"].category_multipliers["Web"] == 1.5
+ assert "Execution" in profiles
+ assert profiles["Execution"].tool_weights["run_powershell"] == 5
 
-def test_save_project_no_root_raises(temp_paths):
- manager = ToolPresetManager(project_root=None)
- preset = ToolPreset(name="fail", categories={})
- with pytest.raises(ValueError, match="Project root not set"):
-  manager.save_preset(preset, scope="project")
+def test_save_bias_profile(temp_paths):
+ manager = ToolPresetManager(project_root=temp_paths["project_dir"])
+ profile = BiasProfile(name="Custom", tool_weights={"test": 1})
+ 
+ manager.save_bias_profile(profile, scope="project")
+ 
+ loaded = manager.load_all_bias_profiles()
+ assert "Custom" in loaded
+ assert loaded["Custom"].tool_weights["test"] == 1
 
-def test_delete_project_no_root_raises(temp_paths):
- manager = ToolPresetManager(project_root=None)
- with pytest.raises(ValueError, match="Project root not set"):
-  manager.delete_preset("any", scope="project")
-
-def test_invalid_scope_raises(temp_paths):
- manager = ToolPresetManager()
- preset = ToolPreset(name="fail", categories={})
- with pytest.raises(ValueError, match="Invalid scope"):
-  manager.save_preset(preset, scope="invalid")
- with pytest.raises(ValueError, match="Invalid scope"):
-  manager.delete_preset("any", scope="invalid")
+def test_delete_bias_profile(temp_paths):
+ project_data = {
+  "bias_profiles": {
+   "to_delete": {"tool_weights": {}}
+  }
+ }
+ with open(temp_paths["project_presets"], "wb") as f:
+  tomli_w.dump(project_data, f)
+  
+ manager = ToolPresetManager(project_root=temp_paths["project_dir"])
+ manager.delete_bias_profile("to_delete", scope="project")
+ 
+ profiles = manager.load_all_bias_profiles()
+ assert "to_delete" not in profiles
diff --git a/tests/test_tool_presets_execution.py b/tests/test_tool_presets_execution.py
index 6a35568..076a530 100644
--- a/tests/test_tool_presets_execution.py
+++ b/tests/test_tool_presets_execution.py
@@ -3,14 +3,14 @@ import asyncio
 from src import ai_client
 from src import mcp_client
 from src import models
-from src.models import ToolPreset
+from src.models import ToolPreset, Tool
 from unittest.mock import MagicMock, patch
 
 @pytest.mark.asyncio
 async def test_tool_auto_approval():
  # Setup a preset with read_file as auto
  preset = ToolPreset(name="AutoTest", categories={
-  "General": {"read_file": "auto"}
+  "General": [Tool(name="read_file", approval="auto")]
  })
  
  with patch("src.tool_presets.ToolPresetManager.load_all", return_value={"AutoTest": preset}):
@@ -39,7 +39,7 @@ async def test_tool_auto_approval():
 async def test_tool_ask_approval():
  # Setup a preset with run_powershell as ask
  preset = ToolPreset(name="AskTest", categories={
-  "General": {"run_powershell": "ask"}
+  "General": [Tool(name="run_powershell", approval="ask")]
  })
  
  with patch("src.tool_presets.ToolPresetManager.load_all", return_value={"AskTest": preset}):
@@ -65,7 +65,7 @@ async def test_tool_ask_approval():
 async def test_tool_rejection():
  # Setup a preset with run_powershell as ask
  preset = ToolPreset(name="AskTest", categories={
-  "General": {"run_powershell": "ask"}
+  "General": [Tool(name="run_powershell", approval="ask")]
  })
  
  with patch("src.tool_presets.ToolPresetManager.load_all", return_value={"AskTest": preset}):
diff --git a/tool_presets.toml b/tool_presets.toml
index 837516d..06f6938 100644
--- a/tool_presets.toml
+++ b/tool_presets.toml
@@ -23,3 +23,15 @@ categories.Python = [
  { name = "py_check_syntax", approval = "auto" },
  { name = "py_get_hierarchy", approval = "auto" }
 ]
+
+[bias_profiles.Balanced]
+tool_weights = {}
+category_multipliers = {}
+
+[bias_profiles.Execution-Focused]
+tool_weights = { run_powershell = 5 }
+category_multipliers = { Runtime = 1.5, Surgical = 1.2 }
+
+[bias_profiles.Discovery-Heavy]
+tool_weights = { web_search = 4, search_files = 4 }
+category_multipliers = { Web = 1.5, Analysis = 1.3 }