Cycles

Cycles is a self-hosted runtime authority for autonomous agents: it reserves budget and checks action exposure before an LLM call or tool dispatch actually fires. The core mechanic is a Reserve-Commit-Deny lifecycle — every action requests a reservation, gets approved or rejected, and only runs if the reservation lands. That ordering is the whole point. Dashboards, token counters and rate limiters tell you what you already spent; Cycles returns 409 BUDGET_EXCEEDED and the host skips the call. The vendor's demos make the difference concrete. A runaway agent is stopped at a $1 cap in roughly 30 seconds (~$5.95 modeled locally; ~$10 in 12s in the accelerated recording). In a tool-exposure scenario, four mocked customer actions execute without Cycles, but the outbound email is skipped once its reservation is rejected. In an illustrative coding-agent loop, a mandatory $15 run budget rejects a protected call around iteration 68 of 240 — $52.80 in modeled spend. Budgets scope across tenants, workflows and runs, with shared pools and tenant-close cascade semantics for SaaS operators who can't let one customer's retry loop drain an allocation everyone shares. Per-action caps carry TTL, grace period and extend support; overage policies, debt and overdraft are configurable; tenant, budget and API key management run through an Admin API. A Decide preflight call, webhook event delivery with scope filtering, Prometheus metrics, Shadow mode for dry-running policies against live traffic, and CyclesEvidence — a verifiable record of each pre-execution decision, denial and settlement — round out the governance surface. SDKs cover Python, TypeScript, Java/Spring and Rust, plus an MCP server for Claude Desktop, Claude Code, Cursor and Windsurf. Deployment is Docker-based with Redis required, and the docs claim the full stack in under five minutes. It is not an LLM gateway and not an observability tool, and the vendor publishes explicit comparison pages against rate limiting,