docs: add Aegis guardrail provider

[Acacian]

Summary

• Add Aegis guardrail provider documentation
  (docs/my-website/docs/proxy/guardrails/aegis.md)
• Add sidebar entry in sidebars.js

What is Aegis?

Aegis is an open-source governance runtime for AI agents
that provides:

• Prompt injection detection (107 patterns)
• PII masking (email, phone, SSN)
• Policy-as-code (YAML-based)
• Audit trail

PyPI: https://pypi.org/project/agent-aegis/

[vercel]

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Project	Deployment	Actions	Updated (UTC)
litellm	Ready	Preview, Comment	Mar 29, 2026 3:05pm

[CLAassistant]

All committers have signed the CLA.

[codspeed-hq]

Merging this PR will not alter performance

✅ 16 untouched benchmarks

---

_{Comparing Acacian:docs/aegis-guardrail (6e7ff28) with main (5812053)}

[greptile-apps]

Greptile Summary

This is a documentation-only PR that adds a new page for the Aegis open-source guardrail library and a corresponding sidebar entry. The previous version of this PR was revised to address a prior review comment about guardrail: aegis not being registered in LiteLLM's guardrail registry; the current approach correctly drops that config in favour of Aegis's own auto-instrumentation mechanism (monkey-patching litellm.completion/acompletion).

Key observations:

• No code changes — entirely documentation and sidebar wiring.
• Integration model is fundamentally different from every other provider in the guardrails/ section. All other listed guardrails integrate via the LiteLLM guardrail registry and config.yaml; Aegis patches litellm at the Python module level instead. This distinction is partially explained in the doc but the downstream implication — that per-request guardrail selection (\"guardrails\": [\"aegis\"]) is not supported — is not mentioned.
• The LiteLLM Proxy AEGIS_INSTRUMENT=1 usage section is accurate but lacks an explanation of the startup hook mechanism, which users will need if they try to debug why instrumentation doesn't appear to take effect.
• No test, security, or backward-compatibility concerns apply (docs only).

Confidence Score: 5/5

Safe to merge — documentation only, no code changes, and the prior critical issue has been resolved

All remaining findings are P2 style suggestions (missing explanatory caveats). The previous P0/P1 concern about a non-functional guardrail: aegis config entry has been addressed by replacing that approach with auto-instrumentation. No runtime behaviour of LiteLLM is affected.

docs/my-website/docs/proxy/guardrails/aegis.md — proxy instrumentation and global-activation caveats could be clearer

Important Files Changed

Filename	Overview
docs/my-website/docs/proxy/guardrails/aegis.md	Adds Aegis guardrail documentation using auto-instrumentation (monkey-patching) rather than LiteLLM's native guardrail registry — fundamentally different from every other provider in this section; missing caveats about global vs. per-request activation and proxy startup hook mechanism
docs/my-website/sidebars.js	Adds proxy/guardrails/aegis entry at the top of the third-party guardrail list; no issues

Sequence Diagram

sequenceDiagram
    participant U as User Code / Proxy
    participant A as Aegis (monkey-patch)
    participant L as litellm.completion (original)
    participant LLM as LLM Provider

    Note over U,A: Startup — aegis.auto_instrument() called
    A->>L: wraps litellm.completion & acompletion

    U->>A: litellm.completion(model, messages)
    A->>A: run guardrails (injection, PII, policy)
    alt Blocked
        A-->>U: raise AegisGuardrailError
    else Allowed
        A->>L: forward call (original completion)
        L->>LLM: API request
        LLM-->>L: response
        L-->>A: response
        A->>A: post-call audit logging
        A-->>U: response
    end

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_{Reviews (3): Last reviewed commit: "docs: fix non-functional start_proxy.py ..." | Re-trigger Greptile}

[greptile-apps]

No backend implementation for guardrail: aegis

The documentation instructs users to configure guardrail: aegis, but this value is not registered anywhere in the LiteLLM codebase. Using this configuration will immediately raise a runtime ValueError rather than working as documented.

The lookup chain in litellm/proxy/guardrails/guardrail_registry.py is:

1. Check guardrail_initializer_registry (built from SupportedGuardrailIntegrations enum + auto-discovered guardrail_hooks/*/)
2. Check if guardrail_type contains "." (custom module path)
3. Otherwise → raise ValueError(f"Unsupported guardrail: {guardrail_type}")

"aegis" is absent from both SupportedGuardrailIntegrations (litellm/types/guardrails.py) and the litellm/proxy/guardrails/guardrail_hooks/ directory. Every user who follows this guide will receive:

ValueError: Unsupported guardrail: aegis

The integration code (a guardrail_hooks/aegis/ module registered under SupportedGuardrailIntegrations.AEGIS) must be merged into LiteLLM before this documentation can be published. If the intent is to use the custom guardrail path (guardrail: aegis_module.AegisGuardrail), the documentation should instead reflect that pattern.