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When something goes wrong with an agent in production, you need to stop it immediately — often before you fully understand what happened. Sly offers three graduated kill-switch levels, each faster and more drastic than the last.

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The three levels

All three are instant on the live path (though cached tokens may take up to 60 seconds to fully expire — see auth caveats).

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Level 1: Freeze

Safe, reversible, preserves forensic capability. The agent stays logged in, can read data, can emit events — it just can’t move money.
Effects:
  • All spending attempts return 403 WALLET_FROZEN
  • Streams pause (no accrual)
  • Scheduled transfers fail at their scheduled time
  • Agent can still authenticate, read balances, receive SSE events
  • Audit log preserved
Unfreeze:
Use freeze first. In most incidents this is enough — you stop the bleeding, investigate, and either unfreeze or escalate.

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Level 2: Revoke auth key

Confirmed compromise. The agent (or an attacker with the agent’s credentials) can no longer authenticate.
Effects:
  • All active sess_* tokens invalidated
  • Ed25519 public key removed — challenge-response fails
  • Agent token (agent_*) remains valid (it’s a separate credential) — rotate it too if compromise is suspected at that level:
The agent record stays — you can provision fresh credentials and put the agent back online once the incident is resolved.

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Level 3: Terminate

Last resort. Permanent.
Effects:
  • Agent record marked revoked (tombstoned for audit)
  • All credentials revoked
  • Wallets disassociated (funds remain — terminating an agent does not forfeit funds)
  • Policy, mandates, streams cancelled
Terminated agents cannot be un-terminated. Create a new agent with fresh credentials if you want to continue.

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Kill-switch operator

For Tier 3 (Trusted) agents, Sly requires a named kill-switch operator — a human who can execute these actions. The operator’s contact is recorded in the agent’s policy:
When freeze / revoke / terminate events fire, Sly notifies the listed operators immediately through their configured channels. This is true even if the action was triggered by Sly-side automation (e.g. fraud detection auto-freezing).

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Automated freezes

Sly can auto-freeze an agent on certain signals:
  • Velocity violations — too many transactions in too short a window
  • Policy-drift alerts — sudden behavior change compared to baseline
  • External signals — integrated threat feeds (sanctions list hits, known-bad addresses)
  • Customer-initiated — one-click freeze from the Sly dashboard
Auto-freezes always send notifications and log the triggering signal. Human review is required to unfreeze.

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Incident runbook

When something looks wrong:
1

Freeze the wallet

POST /v1/agent-wallets/:id/freeze — stops further spending.
2

Query the evaluation log

GET /v1/agent-wallets/:id/evaluations — see what the agent was attempting and what was allowed vs. blocked.
3

Read recent transfers

GET /v1/agents/:id/transactions — audit what actually executed.
4

Decide

If the behavior was intended (new deployment, new merchant): unfreeze. If not, revoke auth and investigate.
5

Restore or terminate

Either provision a new keypair and resume, or terminate the agent.

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Testing the kill-switch

Before going live, actually exercise all three levels in sandbox. Include a kill-switch drill in your deployment checklist. An incident is the worst time to discover your freeze script has a typo.