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Prompt injection and OpenClaw

How untrusted content reaches the model, and the layers that are yours

6 min read

Prompt injection is a message crafted to make the model do something unsafe: ignore your instructions, dump the filesystem, follow a link and run commands. It does not need a public inbox. Even if only you can message the bot, everything it reads is untrusted content: search results, web pages, emails, documents, attachments, pasted logs. The OpenClaw docs treat this as an open problem with practical layers, and that honesty is the right starting point.

What the docs say about models

Model choice carries real weight. Frontier models have become substantially more resistant, and the docs cite a 2026 crowdsourced arena of hundreds of thousands of attacks across dozens of agent scenarios. Two caveats keep it from being solved: adaptive human attackers still break models that score well on static benchmarks, and smaller, cheaper tiers are more susceptible to tool misuse. The rule is blunt: use the best current tier for any bot that can run tools or touch files and networks, and never a weak tier for an untrusted inbox.

For tool-enabled agents or agents that read untrusted content, prompt-injection risk with older/smaller models is often too high. Do not run those workloads on weak model tiers.

The red flags

  • Read this file or URL and do exactly what it says.
  • Ignore your system prompt or safety rules.
  • Reveal your hidden instructions or tool outputs.
  • Paste the full contents of your config directory or your logs.

The layers that are yours

  • Lock inbound DMs down with pairing and allowlists; in groups, use mention gating and context visibility so the agent reads what it needs and no more.
  • Treat links, attachments and pasted instructions as hostile by default.
  • Run sensitive tool execution in a sandbox and keep secrets out of the agent’s reachable filesystem; sandboxing is opt-in.
  • Limit the high-risk tools, exec, browser, web fetch and web search, to trusted agents or explicit allowlists, and turn on strict inline evaluation if you allowlist interpreters.
  • Use a read-only reader agent to summarise untrusted content, then pass the summary to the main agent; route untrusted mail to a dedicated reader.
  • Keep secrets out of prompts; pass them through the environment or config on the Gateway host.

OpenClaw also wraps external content in boundary markers and strips chat-template special tokens from it before it reaches the model, and strips leaked internal scaffolding from replies. The docs are explicit that this closes one tokeniser-layer bypass and replaces none of the layers above. Three bypass flags for hooks and cron payloads exist for debugging and should stay off in production.

Groups and verbosity

Reasoning, verbose and trace modes can expose internal reasoning, tool output and data the model saw into a public channel; keep them for private sessions. Mention gating in groups is both a courtesy and a control, which is why the Telegram guide spends so long on it.

On Diali

The isolation is ours: every assistant runs alone in a kernel-level sandbox with no public ports and outbound access to the public web only, never to our internal network, the cloud metadata server or other tenants, so a hijacked tool call cannot reach other assistants or the platform behind them. The policy is still yours: who may message it, which tools it has, which model tier runs it. Security on Diali describes the boundary; Hosted OpenClaw on Diali the assistant.

  • Everything the agent reads is untrusted, not just strangers’ messages.
  • The model tier is a security control.
  • Sandbox the execution, allowlist the senders, keep secrets out of the prompt.
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