Cite as: Real Problem AI problem “How do I put a hard spending cap on my OpenAI or Anthropic API key?”. Opportunity score 8.5 out of 10 (severity 9, AI feasibility 8, market signal 9, competition gap 8). Category AI / Agents. Trend Agents. Source signal: Hacker News discussion of Simon Willison's post "We're going to need default hard budget caps on pretty much everything", 4 October 2026, 313 comments; a separate Ask HN post on 26 September 2026 claims Codex agents ran up about USD 78,000 without approval.. Canonical URL: https://www.realproblem.ai/idea/how-do-i-set-a-hard-spending-cap-on-my-openai-or-anthropic-api-key.
How do I put a hard spending cap on my OpenAI or Anthropic API key?
Coding agents and background routines can fan out into hundreds of parallel runs overnight, and most AI and cloud billing still offers alerts after the fact rather than a hard stop that actually cuts the key off at a set amount.
Who has it: Solo builders, small dev teams and agencies running coding agents, scheduled AI jobs and API keys on a company card.
- Severity9/10
- Feasible today8/10
- Market signal9/10
- Competition gap8/10
Heard in public
“It should be illegal to not have them”
Quoted word for word from the public post linked below. Nobody submitted it to Real Problem AI.
Hacker News discussion of Simon Willison's post "We're going to need default hard budget caps on pretty much everything", 4 October 2026, 313 comments; a separate Ask HN post on 26 September 2026 claims Codex agents ran up about USD 78,000 without approval.What nothing does yet
A drop in budget guard for AI keys: issue a scoped key per agent or job with a hard dollar and token ceiling per hour and per day, kill it the moment the ceiling is hit, and show a live burn rate so a runaway loop is stopped in minutes instead of discovered on the invoice.
Tools that solve this
3 named so far, and where each one stops.
- Provider budget alerts and monthly limits
Mostly email alerts or soft limits at the organisation level, not a per key, per agent, per hour hard stop.
- Virtual cards (Privacy, Revolut, Ramp)
Cap the card, but the charge often lands after the usage, and a declined card can still leave a bill owed.
- LLM gateways such as LiteLLM and Portkey
Can enforce budgets per key, but you have to self host or route every tool through them, which agent harnesses do not do by default.
How you might build it
- 01API proxy that mints scoped keys
- 02Per key token and cost metering
- 03Hard kill switch with webhooks
- 04Provider pricing tables kept current
- 05Slack and SMS alerts
#NOV1 · Canonical URL: https://www.realproblem.ai/idea/how-do-i-set-a-hard-spending-cap-on-my-openai-or-anthropic-api-key