HALO — Python API reference

Generated reference for the Python binding of the HALO harness protocol (halo_agent_harness). For the project overview, the normative protocol, and the decision records, start at the repository root.

• Protocol (normative): docs/spec/harness-protocol.md
• Overview & comparison: root README
• Progress / roadmap: docs/progress.md

Quickstart

from halo_agent_harness import AgentInput, AuthorityLevel, Decision, DecisionAction, Harness


class RefundApprover:
    name = "refund-approver"
    authority_level = AuthorityLevel.BLOCK
    capabilities = frozenset({DecisionAction.ALLOW, DecisionAction.BLOCK})

    def run(self, request, tools):
        if request.context["amount"] > 1000:
            return Decision(DecisionAction.BLOCK, 0.99, "over policy limit")
        return Decision(DecisionAction.ALLOW, 0.75, "within policy")


out = Harness().invoke(RefundApprover(), AgentInput("acme", "u1", context={"amount": 5000}))
# out.decision.auto_enforced was decided by the harness gate — never by the agent

See the API reference for the full surface.