Inside agent-gov: Architecture of an Agent Cost Governance Platform

Sathish Chelliah Posted on May 31 Inside agent-gov: Architecture of an Agent Cost Governance Platform # ai # python # opensource # architecture agent-gov (3 Part Series) 1 Announcing agent-gov: Open-Source AI Agent Cost Governance 2 Inside agent-gov: Architecture of an Agent Cost Governance Platform 3 5 Real-World AI Agent Cost Disasters (And How agent-gov Prevents Them) Inside agent-gov: Architecture of an Agent Cost Governance Platform AI agents orchestrate complex workflows — calling LLMs, scraping pages, querying databases, sending emails. Each call costs real money. Without a governance layer, a single buggy loop can burn through your budget before anyone notices. agent-gov is an open-source reverse proxy that intercepts every tool call your agents make, enforces budgets in real time, and auto-pauses out-of-control agents. Built as a FastAPI service with SQLite persistence, running 45 tests in 0.3 seconds. This post walks through the architecture: the proxy pattern, the four-stage decision tree, cost tracking with a tool registry, multi-tenancy via workspaces, and the lazy auto-reset pattern. The Proxy Pattern Every AI agent tool call passes through agent-gov before reaching the actual tool. The agent sends a POST /proxy/call with its API key, tool name, and estimated cost. agent-gov validates, budgets, and logs — then returns a 200 to approve or a 429 to reject. class ToolCall ( BaseModel ): agent_key : str = Field (...) tool_name : str = Field (...) estimated_cost : float = Field ( 0.0 , ge = 0 ) Enter fullscreen mode Exit fullscreen mode The proxy doesn't execute the tool itself — it guards access. The agent only proceeds if the proxy returns 200. This is the gatekeeper pattern : a lightweight decision layer between the agent and the outside world. Agent -> POST /proxy/call -> agent-gov -> 200/429 -> Agent decides | Calls actual tool | v OpenAI / Browser / API Enter fullscreen mode Exit fullscreen mode Why a proxy instead of a library? A library