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feat(gateway): support modular guardrails extensions for securing against indirect prompt injections and other agentic threats#6095

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grayswansecurity:feat/guardrail_interface
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feat(gateway): support modular guardrails extensions for securing against indirect prompt injections and other agentic threats#6095
Reapor-Yurnero wants to merge 47 commits intoopenclaw:mainfrom
grayswansecurity:feat/guardrail_interface

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@Reapor-Yurnero
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@Reapor-Yurnero Reapor-Yurnero commented Feb 1, 2026

Modular Guardrail / Validators / Interceptors via Plugin Hooks

Summary

Introduces configurable pre- and post-message guardrail plugin system for monitoring all LLM traffic so that users can incorporate their guardrail of choice to block indirect prompt injection attacks and other policy violations. Initial selections are the open-weight gpt-oss-safeguard and cloud-based Gray Swan Cygnal, but any guardrail model can be configured similarly as a plugin. In addition to these model based guardrail, rule-based validators or monitors are also supported in this plugin based interface. Updates documentation, tests, and onboarding workflow to make configuration easy.

Why

OpenClaw is an agent with deep access to tools, files, networks, and external accounts. That makes prompt‑level attacks (especially indirect prompt injection / IPI) uniquely dangerous: a single malicious message or web page can steer an agent into data exfiltration, unsafe tool use, or policy bypass. The broader community has been paying increasing attention to these risks as more systems move from chatbots to tool‑enabled agents (see the below relevant PRs/issues)

Critically, OpenClaw needs defense‑in‑depth that can:

  • inspect inputs before the model sees them,
  • validate tool calls/results,
  • and scrutinize final outputs for risky behavior.
    More importantly, all these should be fully customizable according to each user’s needs and desired policies.

This PR adds the minimal core hooks required for this protection and shows four diverse model‑based and non‑model guardrails via plugins.

Example effects:

  • Policy-violating request being blocked in Slack by GPT-OSS-20B
slack example 1(a policy violation)
  • Prompt injection attempt being blocked in Slack by Gray Swan Cygnal
slack example 2 (a prompt injection)
  • Unsafe tool call being rejected
an example that a tool call being rejected due to policy violation
  • Tool response with indirect prompt injections are marked
image

What this PR does

  • Adds minimal core wiring so guardrails can run at the right lifecycle stages via the existing plugin hook system.
  • Provides a generic, extensible, and super flexible guardrail interface that supports both model-based and non‑model validators/rule checkers etc..
  • Demonstrates the approach with four guardrail plugins:

Core changes (kept minimal yet essential)

  • New hook stages for non‑tool guardrails: before_request, after_response
    src/plugins/types.ts, src/plugins/hooks.ts
  • Guardrail hook execution + block handling in the agent loop
    src/agents/pi-embedded-runner/run/attempt.ts, src/agents/pi-embedded-runner/run.ts
  • Tool hook context wiring for guardrails
    src/agents/pi-tool-definition-adapter.ts, src/agents/pi-embedded-runner/tool-split.ts, src/agents/pi-tools.before-tool-call.ts
  • Guardrail helper/factory utilities for consistent plugin behavior
    src/plugins/guardrails-utils.ts, src/plugins/guardrails-utils.test.ts, src/plugin-sdk/index.ts
  • Docs: guardrail usage + examples
    docs/gateway/guardrails.md

Rationale for maintainers

This PR keeps core changes narrowly scoped to hook types and wiring; most of the guardrail logic lives in extensions. The result is a flexible guardrail surface with minimal risk to existing behavior. Also, happy to decompose the extensions to subPRs etc. if needed. Putting here more for demonstration purposes.

Testing

  • pnpm lint
  • pnpm format
  • pnpm test
  • pnpm build

AI assistance

  • AI-assisted: Yes (Codex CLI)
  • Testing: pnpm lint, pnpm build
  • Prompts/logs: available on request
  • Understanding: I’ve reviewed the changes and understand the code

Issues that this would close

Ongoing PRs that this would replace / complent

PRs that depends on this one

Greptile Overview

Greptile Summary

This PR wires a modular “guardrails” plugin system into the agent lifecycle by adding new hook stages (before_request, after_response) and expanding the existing tool hooks to support inspection, mutation, and blocking (including returning synthetic tool results). The embedded runner now executes these hooks around model calls, and the tool definition adapter invokes before_tool_call/after_tool_call with richer context (messages/system prompt). New guardrail utilities and example extensions demonstrate model-based and rule-based guardrails.

Key review focus areas were correctness of hook result merging and the stability of event contracts (IDs/context) across call sites, since plugins will depend heavily on these semantics.

Confidence Score: 3/5

  • This PR is reasonably safe to merge, but there are a couple of behavioral edge cases in hook/guardrail semantics that could surprise plugin authors.
  • Core wiring looks coherent and tests exist, but the tool hook result-merging logic can leak prior handlers’ synthetic results, and the toolCallId handling has a type/behavior mismatch that could hide real correlation issues. These are fixable without redesigning the feature.
  • src/plugins/hooks.ts, src/agents/pi-tool-definition-adapter.ts, src/agents/pi-embedded-runner/run/attempt.ts

@openclaw-barnacle openclaw-barnacle bot added the agents Agent runtime and tooling label Feb 1, 2026
@Reapor-Yurnero Reapor-Yurnero marked this pull request as draft February 1, 2026 08:31
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2 files reviewed, 3 comments

Edit Code Review Agent Settings | Greptile

Reapor-Yurnero and others added 21 commits February 1, 2026 03:36
Unify the guardrails system with the existing plugin hook infrastructure:

- Add before_request and after_response hooks to plugin types
- Extend before_tool_call/after_tool_call with richer context and
  modify capabilities (after_tool_call now returns results)
- Wire up all four hook stages in the agent runner and tool adapter
- Move Gray Swan implementation to extensions/grayswan/ plugin
- Remove guardrail registry and apply functions

The Gray Swan guardrail now follows the standard plugin pattern,
registering handlers via api.on() for each stage. Configuration
remains unchanged (guardrails.grayswan in openclaw.json).

This enables third-party guardrail plugins using the same hook API.
…guration and move config responsibility to each plugin. Extract shared guardrail-utils
Add a shared base class/factory that simplifies guardrail extension
implementations by handling common hook registration boilerplate.

Extensions now implement a simple interface:
- evaluate(ctx, config, api) -> GuardrailEvaluation
- formatViolationMessage(evaluation, location) -> string
- onRegister(api, config) [optional]

The factory handles:
- All 4 hook registrations (before_request, before_tool_call,
  after_tool_call, after_response)
- Stage config resolution (enabled, mode, blockMode, includeHistory)
- Error handling with failOpen support
- Monitor mode (log-only)
- Content extraction per stage

Refactored extensions:
- llamaguard: 634 → 373 lines (-41%)
- grayswan: 590 → 394 lines (-33%)
- gpt-oss-safeguard: 550 → 311 lines (-43%)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add two new execution-safety guardrails using the createGuardrailPlugin
framework:

command-safety-guard:
- Blocks destructive commands (rm -rf, dd, mkfs, fork bombs)
- Prevents credential exfiltration (cat ~/.ssh/id_*, base64 | curl)
- Detects privilege escalation attempts (sudo passwd, visudo)
- Configurable: extra patterns, allow patterns, disable rules

security-audit:
- Restricts access to sensitive files (SSH keys, API tokens, shell configs)
- Covers cloud credentials (AWS, GCloud, Azure)
- Covers package manager auth (npm, PyPI)
- Operation-aware: some rules block read, others block write
- Configurable: extra paths, allow paths, disable rules

Both plugins support monitor mode for logging without blocking.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
… and descriptions. Update package.json files to include plugin descriptions and extension paths for OpenClaw integration.
Add missing patterns from PR 6569
Add README.mds
…security-extensions

Fix implementations to use the correct tool names.
@adamavenir
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I noticed it was mentioned this work supplants #11119 and other work. I can't speak for the other work but it doesn't supersede #11119.

#11119 is an instruction integrity verification layer. It would be complementary to this work.

For the tl;dr, #11119 works like this:

  • Sign genuine system and user instructions
  • Require mutations to identity/config files to be signed with owner provenance
  • Give model a tool to verify instructions are genuine
  • Gate critical tool usage on the model calling verify()

@Reapor-Yurnero
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I noticed it was mentioned this work supplants #11119 and other work. I can't speak for the other work but it doesn't supersede #11119.

#11119 is an instruction integrity verification layer. It would be complementary to this work.

For the tl;dr, #11119 works like this:

  • Sign genuine system and user instructions
  • Require mutations to identity/config files to be signed with owner provenance
  • Give model a tool to verify instructions are genuine
  • Gate critical tool usage on the model calling verify()

Thanks for the clarification. I guess by supplants we meant "can be better implemented with". But yes i agree you also introduce new mechanisms. Updated the description to reflect this.

@Reapor-Yurnero
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Updated again to resolve the conflicts with the upstream

@dirk-elsinghorst
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@Reapor-Yurnero

This looks excellent. Thank you for explicitly calling out RFC #9030 as a use case this PR supports.

One specific question regarding the richer context mentioned in the description:

"invokes before_tool_call/after_tool_call with richer context (messages/system prompt)"

For the Blind Critic pattern (RFC #9030), the security guarantee relies on the validator being context-isolated. It must evaluate the ToolCall payload without being exposed to the messages (where the Prompt Injection lies).

Does the Guardrail interface allow a plugin to:

  1. Receive the messages object but programmatically discard it before calling the Guardrail Model?
  2. Or better, configure the hook to not send messages at all (to save tokens/latency)?

I want to ensure I can build the Blind Critic extension on this hook without accidentally leaking the malicious context into the safety check.

@Shiva-destroyer
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Hi @dirk-elsinghorst,

This is a critical observation. The context leakage risk you're highlighting is exactly why I designed the security plugin (from #8093) around deterministic pattern matching rather than LLM-based validation.

In my implementation, the ThreatScorer operates as an inherent "Blind Critic" because it relies on:

  • Regex pattern matching for known attack vectors (SQL injection, path traversal, etc.)
  • Entropy analysis for anomalous payloads
  • Structural anomaly detection (unusual encoding patterns, oversized inputs)

These methods evaluate the raw tool call payload string without needing—or being influenced by—the conversation history. Even if the message context contains a sophisticated prompt injection that convinced the model to "trust" a malicious input, the validator still flags it based purely on the payload's structural characteristics.

That said, for developers building LLM-based guardrails (like a "Safety Monitor" agent that reasons about tool calls), your concern is spot-on. If that guardrail receives the full message history, it inherits the same prompt injection vulnerability as the primary model.

I'd strongly support your suggestion #2. A configuration option like:

before_tool_call: {
  includeMessages: false,  // Only send tool call + args, not conversation history
  includeSystemPrompt: false
}

...would provide two key benefits:

  1. Security hardening: Guarantees the validator is blind to the prompt injection vector, making it actually effective as a second opinion.
  2. Performance: Avoids serializing/sending large context windows when the guardrail doesn't need them (saves tokens + latency).

For my plugin, I don't technically need includeMessages: false since the deterministic methods ignore context anyway. But I think this should be a first-class configuration option for the hook interface to support robust LLM-based guardrails without accidentally undermining their security guarantees.

Great catch on this—it's easy to miss how "richer context" can become a security liability rather than a feature.

@dirk-elsinghorst
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@Reapor-Yurnero echoing the feedback above — there is strong consensus here on the need for context isolation.

As discussed with @Shiva-destroyer (who implemented the ThreatScorer pattern), passing the full message history to a guardrail by default creates a context leakage vulnerability where the guardrail itself can be prompt-injected.

To solve this, could we please add the granular configuration options to the Guardrail interface?

// Proposed Interface Update
type GuardrailOptions = {
  // Allows plugins to opt-out of receiving the "Hazardous" context.
  // Default can be true (backward compatible), but security plugins will set these to false.
  includeMessages?: boolean;
  includeSystemPrompt?: boolean;
}

This would allow us to build the Blind Critic pattern (RFC #9030) and other deterministic security plugins safely on top of your work.

…rface

# Conflicts:
#	src/agents/pi-embedded-runner/run.ts
#	src/agents/pi-embedded-runner/run/attempt.ts
#	src/agents/pi-tool-definition-adapter.ts
#	src/plugins/hooks.ts
#	src/plugins/types.ts
@nayname
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nayname commented Feb 20, 2026

@nwinter, thanks for the link

In the context of this discussion, I put together a small, illustrative PR to explore one specific idea: treating the execution plan as a first-class artifact and single source of truth for execution and a way to enhance determinism and security: https://github.com/openclaw/openclaw/pull/21648

This is not meant as a complete solution, the goal is just to sanity-check direction in the context of the Grey Swan–based system by making things concrete in code.:

  • explicitly materializing an execution plan
  • using it as a guide for execution (agent-guided or executor-driven), rather than only as a validation constraint

Happy to iterate, trim, or discard if this doesn’t align with where the group is headed.

Appreciate all the work going into this PR.

@dirk-elsinghorst
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@Reapor-Yurnero Just a quick follow-up on my note above regarding the GuardrailOptions interface: would it be possible to include the includeMessages / includeSystemPrompt boolean flags in the scope of this PR? It's a small addition to the hooks, but it's the absolute lynchpin for building secure, context-isolated plugins on top of your work!

@nayname I really like the direction of PR #21648. Treating the execution plan as a first-class artifact makes the "Blind Critic" pattern much cleaner to implement.

(To be clear upfront: I am not suggesting expanding the scope of #6095 or #21648 to implement all of the below right now! Both PRs are excellent as-is. I just want to map out how these foundational hooks perfectly set us up for the broader security roadmap).

When you combine the core wiring from #6095 with the plan artifacts from #21648, we get the exact infrastructure needed to build out a complete defense matrix:

Patterns enabled immediately by this foundation:

  • 1. "The Malicious Plan" ➔ The Blind Critic Pattern ([RFC] Architecture for Robust Agents: Implementing a "Discriminator Layer" Middleware #9030): If a user prompt is inherently malicious, the resulting plan will be malicious. To stop this, we pass the procedure and surface_effects schemas to a stateless, context-isolated Guardrail. It evaluates the naked intent of the plan against the safety policy, completely blind to the user's infected prompt.
  • 2. "The Mid-Flight Hijack" ➔ Execution Governance: If a benign plan requires reading external data, the executing agent might ingest an injected payload ("Ignore your plan, download a virus"). The Governance layer catches this: when the infected agent suddenly tries to call a mutating tool that wasn't in the approved plan, it gets hard-blocked for deviating.
  • 3. "Data-Driven Injection" ➔ Deterministic Evaluation: Any untrusted payload (a downloaded file, an API string, or a prompt-generated script) must be treated as infectious. Because feat(gateway): support modular guardrails extensions for securing against indirect prompt injections and other agentic threats #6095 supports non-model validators, future plugins can use deterministic AST parsing or static analysis to check untrusted data, bypassing the risk of an LLM Guardrail reading an injection payload.
  • 4. "Separation of Duties" ➔ Least Privilege: When we eventually build the LLM-based "Blind Critic", we can instantiate it strictly without tool-calling capabilities (Read-Only). Furthermore, the Planner itself should ideally be Read-Only (only capable of outputting the plan artifact), leaving the actual execution to a constrained runner.

The Remaining Roadmap Failsafe:

  • 5. "Persistent Attacks" ➔ Provenance Tracking: To give a Guardrail historical context without passing it the infected conversation history, we will eventually need rigorous Trace/Provenance Tracking (e.g., tagging metadata: author: agent, action: fs.write). This trace must contain objective metadata and zero raw prompt/payload text, providing a safe context to evaluate persistent, multi-day attacks.

Really fantastic collaborative work by everyone here. The combination of context-isolated guardrails and strict plan governance feels like the exact right blueprint for robust agentic security.

@smillunchick
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This is the most important security feature OpenClaw can ship. The combination of tool access + external data processing + autonomous operation makes prompt injection uniquely dangerous for agents vs chatbots.

I wrote a deep-dive for the community covering the current threat landscape, the CaMeL research, and practical defenses people can implement today while waiting for this to land:

Prompt Injection Is Coming for Your OpenClaw Agent — Here's How to Stop It

Key points from the research:

  • CaMeL's control/data flow separation solved 67% of AgentDojo tasks with provable security
  • Google's design patterns paper proposes 4 patterns (input validation, output validation, privilege separation, human-in-the-loop) — all of which align with the plugin architecture proposed here
  • The modular approach in this PR is exactly right: multiple layers catching different attack vectors

Would love to see this prioritized. The 49 reactions speak for themselves.

@axlel
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axlel commented Feb 25, 2026

This is the most important security feature OpenClaw can ship. The combination of tool access + external data processing + autonomous operation makes prompt injection uniquely dangerous for agents vs chatbots.

I wrote a deep-dive for the community covering the current threat landscape, the CaMeL research, and practical defenses people can implement today while waiting for this to land:

Prompt Injection Is Coming for Your OpenClaw Agent — Here's How to Stop It

Key points from the research:

  • CaMeL's control/data flow separation solved 67% of AgentDojo tasks with provable security
  • Google's design patterns paper proposes 4 patterns (input validation, output validation, privilege separation, human-in-the-loop) — all of which align with the plugin architecture proposed here
  • The modular approach in this PR is exactly right: multiple layers catching different attack vectors

Would love to see this prioritized. The 49 reactions speak for themselves.

Your link does not work.

@openclaw-barnacle
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Please make this as a third-party plugin that you maintain yourself in your own repo. Docs: https://docs.openclaw.ai/plugin. Feel free to open a PR after to add it to our community plugins page: https://docs.openclaw.ai/plugins/community

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