Function Calling (Tools)

Overview

OpenRegister supports function calling (also known as tools), enabling AI agents to perform actions and retrieve information from the system. Agents can manage registers, schemas, objects, applications, and other agents through natural language.

⚠️ Provider Support

Provider	Function Calling Support	Status
OpenAI	✅ Fully Supported	Excellent
Ollama	✅ Supported	Good with compatible models
Fireworks AI	❌ Not Implemented	Use OpenAI or Ollama

🎯 Recommended Models for Tool-Oriented Agents

For agents that need to use tools (function calling), model selection is critical. Not all models support function calling reliably.

Ollama Models - Function Calling Performance

Model	Function Calling	Performance	Recommended For
mistral-nemo	⭐⭐⭐⭐⭐ Excellent	Fast, reliable tool execution	RECOMMENDED for all tool agents
llama3.2:3b	⭐⭐⭐ Good	Lightweight, decent tool support	Basic tool usage, resource-constrained
llama3.1:8b	⭐⭐⭐⭐ Very Good	Reliable function calling	Alternative to mistral-nemo
mistral:7b	⭐⭐ Fair	Inconsistent tool calling	NOT recommended for tools
qwen2:0.5b	⭐ Poor	Minimal function support	Only for chat, not tools
phi3:mini	⭐⭐ Fair	Limited tool support	NOT recommended for tools

Installation

To install Mistral Nemo (recommended for tool agents):

docker exec openregister-ollama ollama pull mistral-nemo

Agent Configuration

For tool-oriented agents, configure:

{
  'provider': 'ollama',
  'model': 'mistral-nemo',
  'temperature': 0.3,
  'tools': ['opencatalogi.cms', 'openregister.objects']
}

Why Mistral Nemo?

• ✅ Reliable function execution - Consistently calls tools when appropriate
• ✅ Proper parameter handling - Correctly formats function arguments
• ✅ Low hallucination - Doesn't invent functions or parameters
• ✅ Fast inference - Reasonable speed even on CPU
• ✅ Good context retention - Remembers conversation history well

⚠️ Important Notes

Function calling is NOT yet implemented for Fireworks AI. If you want to use tools, you must:

1. Configure OpenAI or Ollama as your chat provider
2. Use a function-calling compatible model (see table above)
3. Ensure your agent is configured with at least one tool
4. Test with natural language commands (e.g., 'List all applications')

For Ollama users: We strongly recommend mistral-nemo for any agent that needs to use tools. Other models may describe what they would do instead of actually executing functions.

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Available Tools

1. Register Tool (openregister.register)

Manage registers (collections of schemas and objects).

Capabilities:

• List all accessible registers
• Get register details by ID or slug
• Create new registers
• Update register configuration
• Delete registers

Example queries:

• 'Show me all registers'
• 'What is in the products register?'
• 'Create a new register called customers'

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2. Schema Tool (openregister.schema)

Manage schemas (define object structure and validation).

Capabilities:

• List all accessible schemas
• Get schema details including properties
• Create new schemas
• Update schema configuration
• Delete schemas

Example queries:

• 'List all schemas in the products register'
• 'Show me the person schema'
• 'Create a schema for orders with fields: id, customer, total'

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3. Objects Tool (openregister.objects)

Manage objects (data records conforming to schemas).

Capabilities:

• Search and filter objects
• Get object details
• Create new objects
• Update existing objects
• Delete objects

Example queries:

• 'Find all persons named John'
• 'Show me object 123 from the products register'
• 'Create a new product with name: Widget, price: 10'

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4. Application Tool (openregister.application)

Manage applications (software modules in your organisation).

Capabilities:

• List all accessible applications
• Get application details
• Create new applications
• Update application configuration
• Delete applications

Example queries:

• 'List all applications'
• 'What applications are available?'
• 'Create an application called HR Portal'

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5. Agent Tool (openregister.agent)

Manage AI agents (self-management capability).

Capabilities:

• List all accessible agents
• Get agent configuration
• Create new agents
• Update agent settings
• Delete agents

Example queries:

• 'Show me all agents'
• 'Create a support agent for customer questions'
• 'What is the configuration of agent X?'

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Configuration

Enabling Tools for an Agent

1. Navigate to Settings → AI → Agents
2. Edit or create an agent
3. Select the tools you want to enable (e.g., 'Application Management')
4. Save the agent

Testing Function Calling

1. Ensure you are using OpenAI or Ollama (NOT Fireworks AI)
2. Create or edit an agent and enable at least one tool
3. Start a conversation with the agent
4. Ask the agent to perform an action:
   • 'List all applications'
   • 'Create a register called test'
   • 'Show me schema 5'

Checking the Logs

Function calls are logged for debugging:

docker logs -f master-nextcloud-1 | grep 'ChatService.*function'

You should see:

• [ChatService] Prepared functions for LLM - Tools are being sent
• [ChatService] Handling function call - LLM is calling a function
• [ApplicationTool] Listing applications - Function is being executed

If you see:

• Function calling not yet supported for Fireworks AI - You need to switch providers

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How Function Calling Works

1. Agent loads tools: When processing a message, ChatService loads tools configured for the agent
2. Convert to OpenAI format: Tools' getFunctions() returns function definitions in OpenAI format
3. Send to LLM: Functions are included in the chat API request
4. LLM decides: The LLM analyzes the user message and decides if a function call is needed
5. Execute function: If yes, ChatService executes the function via the tool
6. Return result: Function result is sent back to LLM, which formulates a natural language response

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Architecture

Tool Interface

All tools implement ToolInterface:

interface ToolInterface
{
    public function getName(): string;
    public function getDescription(): string;
    public function getFunctions(): array; // OpenAI function format
    public function executeFunction(string $functionName, array $parameters, ?string $userId = null): array;
}

Function Definition Format

Tools return function definitions as plain arrays (OpenAI format):

public function getFunctions(): array
{
    return [
        [
            'name' => 'list_applications',
            'description' => 'List all applications...',
            'parameters' => [
                'type' => 'object',
                'properties' => [
                    'limit' => [
                        'type' => 'integer',
                        'description' => 'Maximum results',
                    ],
                ],
                'required' => [],
            ],
        ],
    ];
}

Tool Registry

The ToolRegistry manages all available tools and maps tool IDs to implementations:

$tool = $this->toolRegistry->getTool('openregister.application');

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Security & RBAC

All tools respect:

• RBAC permissions: Users can only perform actions they have permissions for
• Organisation boundaries: Multi-tenancy is enforced
• Agent configuration: Only enabled tools are accessible
• View restrictions: Objects are filtered by agent's configured views

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Troubleshooting

'Function calling not yet supported for Fireworks AI'

Solution: Change your LLM provider to OpenAI or Ollama in Settings → AI → LLM Configuration.

Tools are not being called

Check:

1. Is the agent configured with tools enabled?
2. Are you using OpenAI or Ollama (not Fireworks)?
3. Is the user message clear and actionable? (e.g., 'List applications' not 'What are applications?')

'Tool not found' warning in logs

Solution: The tool ID in the agent configuration is incorrect. Use the format openregister.register, openregister.application, etc.

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Roadmap

Planned Features

• ✅ Basic function calling (OpenAI/Ollama)
• ⏳ Fireworks AI function calling support
• ⏳ Multi-step function calls (agent chains)
• ⏳ Function call caching
• ⏳ Custom tools via app configuration

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See Also

• RAG Deep Dive - How agents find information
• Agent Configuration - Configure agents and tools
• AI Configuration - Provider setup and AI features