How LangChain implements guardrails: middleware-based safety for agents
kalyan_kpl · x · 2026-09-06
kalyankpl breaks down how to add guardrails to AI apps in LangChain — safety/validation mechanisms that intercept execution across the agent lifecycle.
Use cases
- Preventing PII leakage
- Detecting and blocking prompt injection
- Blocking harmful content
- Enforcing business rules and compliance
- Validating output quality
- Requiring human approval for sensitive actions
Implementation: LangChain does this mainly via middleware, with two complementary approaches — deterministic guardrails (regex, keyword matching, schema validation, business rules, permission checks) and model-based checks as a supplement (rest of post truncated).
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