Tool Selection for LLM Agents: Routing Strategies and Implementation › Worked Example: Multi-Tool Selection

class ToolSelector:
    def __init__(self):
        self.tools = {
            "calculator": {
                "desc": "Perform mathematical calculations",
                "triggers": [
                    "calculate",
                    "compute",
                    "growth rate",
                    "percentage",
                    "sum",
                    "average",
                ],
            },
            "calendar": {
                "desc": "Schedule events and check availability",
                "triggers": [
                    "schedule",
                    "meeting",
                    "remind",
                    "block time",
                    "available",
                    "friday",
                    "next week",
                ],
            },
            "email": {
                "desc": "Send emails and messages",
                "triggers": ["email", "send", "message", "write to", "notify"],
            },
            "search": {
                "desc": "Find information and facts",
                "triggers": [
                    "find",
                    "look up",
                    "search",
                    "get",
                    "figures",
                    "data",
                    "q3",
                    "sales",
                ],
            },
            "notes": {
                "desc": "Save and retrieve notes",
                "triggers": ["save", "remember", "note", "write down", "store"],
            },
        }

    def analyze_intent(self, query):
        """Simple keyword-based analysis for demonstration."""
        query_lower = query.lower()
        detected_tools = []

        for tool_name, metadata in self.tools.items():
            score = sum(
                1 for trigger in metadata["triggers"] if trigger in query_lower
            )
            if score > 0:
                detected_tools.append((tool_name, score))

        # Sort by relevance score
        detected_tools.sort(key=lambda x: x[1], reverse=True)
        return detected_tools

    def create_execution_plan(self, query):
        """Create ordered plan based on dependencies."""
        tools_needed = self.analyze_intent(query)

        # Define dependencies: some tools must run before others
        dependencies = {
            "email": ["calendar"],  # Need meeting scheduled before emailing
            "calculator": ["search"],  # Need Q3 data before calculating growth
        }

        plan = []
        completed = set()

        while len(plan) < len(tools_needed):
            added_this_round = False
            for tool_name, score in tools_needed:
                if tool_name in completed:
                    continue

                # Check if dependencies satisfied
                deps = dependencies.get(tool_name, [])
                if all(d in completed for d in deps):
                    plan.append(
                        {
                            "tool": tool_name,
                            "reason": f"Detected intent: '{self.tools[tool_name]['desc']}'",
                            "params": self._extract_params(tool_name, query),
                        }
                    )
                    completed.add(tool_name)
                    added_this_round = True

            if not added_this_round and len(plan) < len(tools_needed):
                # Circular dependency or missing tool
                break

        return plan

    def _extract_params(self, tool_name, query):
        # Simplified parameter extraction
        params = {}
        if tool_name == "calendar":
            if "friday" in query.lower():
                params["day"] = "Friday"
            if "3 hours" in query:
                params["duration"] = "3 hours"
        elif tool_name == "search":
            if "Q3" in query and "sales" in query:
                params["query"] = "Q3 sales figures"
        elif tool_name == "calculator":
            params["task"] = "growth rate Q2 to Q3"
        elif tool_name == "email":
            params["recipient"] = "team"
            params["subject"] = "Presentation preparation"

        return params

selector = ToolSelector()
complex_query = "I need to prepare a presentation for next week's team meeting. Can you find the sales figures from Q3, calculate the growth rate from Q2, and schedule 3 hours this Friday to work on slides? Also, remind me to email the team about it."
intent_analysis = selector.analyze_intent(complex_query)
plan = selector.create_execution_plan(complex_query)