Approval handlers for Decision.ask_

StandardPermissions(mode=Mode.DEFAULT) returns Decision.ask_(...) when a tool is marked destructive=True. Without an approval handler, ask falls back to deny. The agent never silently bypasses the gate. Wire a handler to surface the decision to a human / Slack / ticket queue:

from loomflow import Agent
from loomflow.core.types import ToolCall
 
async def approve_via_slack(call: ToolCall, user_id: str | None) -> bool:
    """Return True to allow the tool call, False to deny."""
    msg_id = await slack.post(
        channel="#approvals",
        text=f"User {user_id} wants to run {call.tool}({call.args!r}). React 👍 to approve.",
    )
    reactions = await slack.wait_for_reaction(msg_id, timeout=300)
    return "👍" in reactions
 
agent = Agent(
    "...",
    permissions=StandardPermissions(mode=Mode.DEFAULT),
    approval_handler=approve_via_slack,
    tools=[delete_user_data],  # @tool(destructive=True)
)

Failure-mode contract

• Handler returns False → tool result is denied with reason="approval declined"; the run continues, the model sees the denial in the next turn.
• No handler wired (approval_handler=None) → denied with reason="approval required; no approver". Same UX as before M10.4 . Single-tenant code that didn’t want approvals keeps working.
• Handler raises → treated as deny + warning logged.