Approvers

Overview

Approvers enable you to create fine-grained policies for approving tool calls made by models. For example, the following are all supported:

1. All tool calls are approved by a human operator.
2. Select tool calls are approved by a human operator (the rest being executed without approval).
3. Custom approvers that decide to either approve, reject, or escalate to another approver.

Approvers can be implemented in Python packages and the referred to by package and name from approval policy config files. For example, here is a simple custom approver that just reflects back a decision passed to it at creation time:

approvers.py

@approver
def auto_approver(decision: ApprovalDecision = "approve") -> Approver:

    async def approve(
        message: str,
        call: ToolCall,
        view: ToolCallView,
        history: list[ChatMessage],
    ) -> Approval:
        return Approval(
            decision=decision,
            explanation="Automatic decision."
        )

    return approve

Approver Registration

If you are publishing an approver within a Python package, you should register an inspect_ai setuptools entry point. This will ensure that inspect loads your extension before it attempts to resolve approvers by name.

For example, let’s say your package is named evaltools and has this structure:

evaltools/
  approvers.py
  _registry.py
pyproject.toml

The _registry.py file serves as a place to import things that you want registered with Inspect. For example:

_registry.py

from .approvers import auto_approver

You can then register your auto_approver Inspect extension (and anything else imported into _registry.py) like this in pyproject.toml:

Setuptools

[project.entry-points.inspect_ai]
evaltools = "evaltools._registry"

uv

[project.entry-points.inspect_ai]
evaltools = "evaltools._registry"

Poetry

[tool.poetry.plugins.inspect_ai]
evaltools = "evaltools._registry"

Once you’ve done this, you can refer to the approver within an approval policy config using its package qualified name. For example:

approval.yaml

approvers:
  - name: evaltools/auto_approver
    tools: "harmless*"
    decision: approve