> ## Documentation Index
> Fetch the complete documentation index at: https://praison.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Before Tool Definitions Input • AI Agent SDK

> BeforeToolDefinitionsInput: Input for BeforeToolDefinitions hooks.

# BeforeToolDefinitionsInput

> Defined in the [**events**](https://praison.ai/docs/sdk/reference/praisonaiagents/modules/events.md) module.

AI Agent

Input for BeforeToolDefinitions hooks.

Fired right after the advertised tool definitions are assembled for a
request and before they reach the LLM. Hooks should modify or filter the
`tool_definitions` list in place (e.g. `data.tool_definitions[:] = ...`)
to redact parameters, append usage guidance to descriptions, or constrain
the advertised schema per request. This mirrors how BEFORE\_LLM mutates its
payload in place; only in-place mutations are adopted by the runtime.

```mermaid theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
%%{init: {'theme': 'base', 'themeVariables': { 'primaryColor': '#8B0000', 'primaryTextColor': '#fff', 'primaryBorderColor': '#710101', 'lineColor': '#189AB4', 'secondaryColor': '#189AB4', 'tertiaryColor': '#fff' }}}%%

graph LR
    agent["Agent"] -- "uses" --> tool["Tool: BeforeToolDefinitionsInput"]
    tool -- "returns" --> result["Result"]
    style tool fill:#189AB4,color:#fff
    style agent fill:#8B0000,color:#fff
    style result fill:#8B0000,color:#fff
```

## Properties

**tool\_definitions** `List`

No description available.

**model** `str`

No description available.

> [accordion] Internal & Generic Methods
>
> * **to\_dict**: Generic utility method.

## Source

> [card] [View on GitHub](https://github.com/MervinPraison/PraisonAI/blob/main/src/praisonai-agents/praisonaiagents/hooks/events.py#L51)
>
> `praisonaiagents/hooks/events.py` at line 51

***

## Related Documentation

> [card] [Tools Concept](https://praison.ai/docs/docs/concepts/tools)

> [card] [Create Custom Tools](https://praison.ai/docs/docs/guides/tools/create-custom-tools)

> [card] [Tool Development](https://praison.ai/docs/docs/tutorials/advanced-tool-development)


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