Cycles — Budget Authority for AI Agents MCP server
io.github.runcycles/cycles-mcp-server·v0.6.1Runtime budget authority for AI agents — reserve, enforce, reconcile spend across providers
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Cycles — Budget Authority for AI Agents tools (9, 1 write)
write = sends, deletes, buys or postsRead from the package source without running it. The installed server may list more.
cycles_check_balanceCheck current budget balance for a scope. Returns remaining, reserved, spent, allocated, and debt amounts. At least one subject filter (tenant, workspace, app, workflow, agent, or toolset) is required. Do not use as a substitute for cycles_reserve \u2014 balances can change between check and action.
cycles_commitCommit actual usage after an operation completes. Always call this after cycles_reserve whether the operation succeeded or failed. Finalizes the budget charge and releases any unused reserved amount back to the pool.
cycles_create_eventwrite actionRecord a usage event directly without the reserve/commit lifecycle. Use for fire-and-forget metering of completed operations where pre-estimation is not available. The event is applied atomically to all derived scopes.
cycles_decideLightweight preflight check \u2014 ask whether an action would be allowed without reserving budget. Does not create a reservation. Use at workflow start to decide strategy. For concurrency-safe budget locking, use cycles_reserve instead.
cycles_extendExtend the TTL of an active reservation. Use as a heartbeat for long-running operations to prevent the reservation from expiring. Does not change the reserved amount.
cycles_get_reservationGet details of a specific reservation by ID. Returns status, subject, action, reserved amount, timestamps, and affected scopes. Useful for debugging and monitoring long-running operations.
cycles_list_reservationsList reservations, optionally filtered by status (ACTIVE, COMMITTED, RELEASED, EXPIRED) or subject fields. Useful for debugging stuck reservations or auditing budget usage.
cycles_releaseRelease a reservation without committing. Use when an operation is cancelled, skipped, or fails before execution. Returns the released budget amount back to the pool.
cycles_reserveReserve budget before a costly operation (LLM call, tool invocation, external action). Returns a reservation_id to commit or release later. If decision is not ALLOW, do not proceed with the operation. For lightweight preflight checks without reserving, use cycles_decide instead.
Public scan report
scanner v0.1.9 · 2026-09-24 · same rubric, same numbers if you re-run it
- Code scan4 source files scanned25/25
- –Live reliabilityno gateway calls yet and no remote to proben/a
- –Tool poisoningtools not inspected (local package is not executed); not countedn/a
- Auth qualitystatic API keys via environment variables6/15
- Maintenancelast push 0 days ago15/15
- Maintainer identityregistry namespace matches repository owner7/10
How Cycles — Budget Authority for AI Agents compares
Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.
- Safety score
- 82/100
- higher than 63% of 48,255 servers
- Tools
- 9
- the typical server has 7
- Tools that change things
- 11%
- typical: 0%. Fewer write tools means less an agent can break
- Downloads a week
- 37
- more than 28% of 12,191 servers with a package
What its tools let an agent do: 8 read · 1 change
Install Cycles — Budget Authority for AI Agents in Claude Code, Cursor or VS Code
Runs npx -y @runcycles/mcp-server on your machine. Read the scan report first; the gateway never runs local packages.
claude mcp add cycles-mcp-server -- npx -y @runcycles/mcp-server
What the publisher says
From the Cycles — Budget Authority for AI Agents repository's README, as published. We do not edit it. Read it on GitHub
Cycles MCP Server — AI agent runtime control over Model Context Protocol
MCP server that gives any MCP-compatible AI agent (Claude Code, Cursor, Windsurf, custom agents) runtime budget, action, and audit authority — enforce LLM cost limits, tool call caps, action permissions, and audit trails before execution, with zero agent code changes. Connect via MCP and use the budget tools (cyclesreserve, cyclescommit, cyclesrelease, cyclesdecide) directly from the agent's tool-calling loop. Powered by Cycles. See Security Model & Enforcement Boundary for what is enforced server-side versus cooperatively in the agent loop.
Why use this?
Autonomous AI agents (Claude, GPT, custom agents) call LLMs, invoke tools, and hit external APIs — but have no built-in way to cap how much they spend. A single agent loop can burn through hundreds of dollars before anyone notices. Multiply that across tenants and teams, and cost control becomes a real problem.
This MCP server gives any MCP-compatible agent a runtime budget authority: a set of tools to check, reserve, spend, and release budget before and after every costly operation. The agent asks "can I afford this?" before acting, and reports what it actually used afterward.
Who needs this:
- Platform teams building multi-tenant agent systems that need per-customer or per-workspace spend limits
- Agent developers who want agents to self-regulate — degrade to cheaper models when budget is low, skip optional tool calls, reduce retries
- Enterprises deploying AI agents that need guardrails so a runaway agent can't blow through a budget
Why MCP specifically:
MCP is the standard protocol that AI hosts (Claude Desktop, Claude Code, Cursor, Windsurf, custom agents) use to discover and call tools. By exposing Cycles as an MCP server, any MCP-compatible agent gets budget awareness as a plug-in — just add the server to your config. No SDK integration in the agent's own code required.
The server also ships built-in prompts so an AI assistant can help you design your budget strategy, generate integration code, and diagnose budget overruns — not just enforce budgets at runtime.
Use Cases
Coding agent with a per-task dollar cap
You run a Claude Code agent that writes and iterates on code. Each task should cost no more than $5. The agent calls cyclesreserve before every LLM call with a cost estimate in USDMICROCENTS. If the reservation comes back DENY, the agent stops and reports "budget exhausted" instead of silently racking up charges. When the call completes, cycles_commit records the actual token cost so the running total stays accurate.
Multi-tenant SaaS with per-customer budgets
Shortened. The full README is on GitHub.
Nothing above is checked by us. What we check is on the safety report.
Cycles — Budget Authority for AI Agents: common questions
- Is Cycles — Budget Authority for AI Agents MCP server safe?
- Mostly: it is graded B (82/100). Read the Cycles — Budget Authority for AI Agents safety report
- How do I install Cycles — Budget Authority for AI Agents?
- It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.
- Does Cycles — Budget Authority for AI Agents need an API key?
- Yes. The registry entry asks for
CYCLES_API_KEY. - Is Cycles — Budget Authority for AI Agents maintained?
- The last commit was 41 days ago (2026-09-24). The latest release is v0.6.1.
- How does Cycles — Budget Authority for AI Agents compare with other MCP servers?
- safety score 82/100 (higher than 63% of 48,255 servers); tools 9 (the typical server has 7); tools that change things 11% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.