Allowed Tools

Whitelist agent tools by name to prevent collisions in multi-environment setups

Tool whitelisting prevents agent confusion by filtering visible tools to only those explicitly allowed, solving collision problems in multi-environment deployments.

Quick Start

1. Set Environment Variable

   Enable tool whitelisting by setting ALLOWED_TOOLS to a comma-separated list of tool names:

   export ALLOWED_TOOLS="search,send_message"
   

   from praisonaiagents import Agent
   
   agent = Agent(
       name="Assistant",
       instructions="Use only the whitelisted tools",
       tools=["search", "send_message", "extract_pdf"],  # extract_pdf gets filtered out
   )
   
   agent.start("Find recent news and message me a summary")
   
2. Programmatic Usage

   Use the AllowedToolsFilter class directly for more control:

   from praisonaiagents.allowed_tools_filter import AllowedToolsFilter
   
   tool_filter = AllowedToolsFilter()
   available_tools = {"search", "send_message", "extract_pdf"}
   visible_tools = tool_filter.filter_tools(available_tools)
   tool_filter.log_diagnostics()
   
   print(f"Filtered tools: {visible_tools}")
   

---

How It Works

The filter operates at tool registration time, intercepting the complete tool registry and returning only whitelisted tools.

Environment State	Behavior
ALLOWED_TOOLS unset	All tools visible (with collision warning)
ALLOWED_TOOLS=""	Error - empty string not allowed
ALLOWED_TOOLS=search,send_message	Only these tools visible
Unknown tool + CI=true	Strict failure at startup
Unknown tool + dev mode	Warning logged, unknown tools stripped

---

Configuration Options

Option	Type	Default	Description
ALLOWED_TOOLS (env)	str (csv)	unset	Comma-separated tool names to whitelist
HERMES_ONLY_TOOLS (env)	str (csv)	unset	Deprecated backward-compatibility alias
CI (env)	str	unset	When truthy (true/1/yes), unknown tools cause startup failure
env_var_name (constructor)	str	"ALLOWED_TOOLS"	Override the primary environment variable name

AllowedToolsFilter Methods

Method	Returns	Description
filter_tools(available_tools)	Set[str]	Apply whitelist filter to tool set
is_enabled()	bool	Check if filtering is active
get_whitelist()	Optional[Set[str]]	Get current whitelist set
log_diagnostics()	None	Print startup diagnostics report
get_diagnostics()	Dict[str, Any]	Get diagnostics as dictionary

---

Common Patterns

Multi-Environment Composition

Combine YouTube, Twilio, and Gmail tool modules while ensuring agents see only canonical tools:

from praisonaiagents import Agent

# Multiple environments might register overlapping tool names
# ALLOWED_TOOLS ensures deterministic tool selection
agent = Agent(
    name="Communication Assistant", 
    instructions="Handle multimedia communication tasks",
    tools=["youtube_search", "twilio_send", "gmail_send", "search", "send_message"]
)
# Only tools in ALLOWED_TOOLS whitelist will be visible

CI/CD Strict Mode

Catch typos early by enabling strict mode in pipelines:

# In CI environment
export CI=true
export ALLOWED_TOOLS="search,send_message,nonexistent_tool"
# This will fail fast with ValueError instead of silently ignoring typos

Backward Compatibility Migration

Existing projects using HERMES_ONLY_TOOLS continue working:

# Legacy (still works)
export HERMES_ONLY_TOOLS="search,send_message"

# Preferred (takes precedence if both are set)
export ALLOWED_TOOLS="search,send_message"

---

Best Practices

Use exact registered tool names

Tool names are case-sensitive and must match exactly as registered in the tool registry. Use list_tools() to verify available names before whitelisting.

from praisonaiagents.tools import list_tools
print("Available tools:", list_tools())

Enable strict mode in CI pipelines

Set CI=true in automated environments to catch typos in ALLOWED_TOOLS that would otherwise be silently ignored in development.

# In CI/CD pipelines
export CI=true
export ALLOWED_TOOLS="search,send_message"

Prefer ALLOWED_TOOLS over legacy naming

New projects should use ALLOWED_TOOLS instead of the deprecated HERMES_ONLY_TOOLS. The new name is clearer and future-proof.

# ✅ Preferred
export ALLOWED_TOOLS="search,send_message"

# ❌ Deprecated (backward compatibility only)  
export HERMES_ONLY_TOOLS="search,send_message"

Combine with BotConfig for layered security

Environment-variable whitelisting is global and name-based, while BotConfig.allowed_tools provides per-bot runtime filtering. Use both for comprehensive tool security.

from praisonaiagents import Agent, BotConfig

# Global filter (env var): search,send_message,extract_pdf
# Bot-level filter (runtime): search,send_message only
bot_config = BotConfig(allowed_tools=["search", "send_message"])
agent = Agent(name="Bot", bot_config=bot_config)

---

When to Use ALLOWED_TOOLS

Real-World Scenario

User runs an agent in an environment with YouTube, Gmail, and Twilio integrations. Each provides a send_message tool:

1. Without ALLOWED_TOOLS: Agent might pick wrong send_message implementation
2. With ALLOWED_TOOLS: Agent gets deterministic tool set: search,gmail_send,twilio_sms
3. User types: “/summarize latest emails and send alerts”
4. Agent behavior: Uses search for email summary, gmail_send for notifications (not the conflicting tools)

---

Related

Tool Configuration

Environment variables and tool setup

Security Best Practices

Agent and tool security guidelines