apunkt/plano
1
0
Fork 0
mirror of https://github.com/katanemo/plano.git synced 2026-04-25 00:36:34 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 3
plano/guides/prompt_guard.html
adilhafeez 36c2ac23e8 deploy: 37600fd07a
2026-04-18 00:23:50 +00:00

313 lines
No EOL
37 KiB
HTML
Executable file
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html :class="{ 'dark' : darkMode === true }" data-content_root="../" lang="en" x-data="{ darkMode: $persist(window.matchMedia('(prefers-color-scheme: dark)').matches), activeSection: ''}">
<head>
<script>
(function () {
// Set initial color scheme
if ((localStorage.getItem("_x_darkMode") === "true") || (window.matchMedia("(prefers-color-scheme: dark)").matches)) {
document.documentElement.classList.add("dark");
}
// Watch for media preference changes
window.matchMedia("(prefers-color-scheme: dark)").addEventListener("change", (event) => {
localStorage.setItem("_x_darkMode", event.matches);
document.documentElement.classList.toggle("dark", event.matches);
});
})();
</script>
<meta content="width=device-width, initial-scale=1.0" name="viewport"/>
<meta charset="utf-8"/>
<meta content="#ffffff" media="(prefers-color-scheme: light)" name="theme-color"/>
<meta content="#030711" media="(prefers-color-scheme: dark)" name="theme-color"/>
<meta content="width=device-width, initial-scale=1" name="viewport"/>
<title>Guardrails | Plano Docs v0.4.19</title>
<meta content="Guardrails | Plano Docs v0.4.19" property="og:title"/>
<meta content="Guardrails | Plano Docs v0.4.19" name="twitter:title"/>
<link href="../_static/pygments.css?v=73db4dac" rel="stylesheet" type="text/css"/>
<link href="../_static/theme.css?v=979577e3" rel="stylesheet" type="text/css"/>
<link href="../_static/sphinx-design.min.css?v=95c83b7e" rel="stylesheet" type="text/css"/>
<link href="../_static/css/custom.css?v=2929376a" rel="stylesheet" type="text/css"/>
<link href="../_static/awesome-sphinx-design.css?v=b1d4564d" rel="stylesheet" type="text/css"/>
<link href="./docs/guides/prompt_guard.html" rel="canonical"/>
<link href="../_static/favicon.ico" rel="icon"/>
<link href="../search.html" rel="search" title="Search"/>
<link href="state.html" rel="next" title="Conversational State"/>
<link href="observability/access_logging.html" rel="prev" title="Access Logging"/>
</head>
<body :class="{ 'overflow-hidden': showSidebar }" class="min-h-screen font-sans antialiased bg-background text-foreground" x-data="{ showSidebar: false, showScrollTop: false }">
<div @click.self="showSidebar = false" class="fixed inset-0 z-50 overflow-hidden bg-background/80 backdrop-blur-sm md:hidden" x-cloak="" x-show="showSidebar"></div><div class="relative flex flex-col min-h-screen" id="page"><a class="absolute top-0 left-0 z-[100] block bg-background p-4 text-xl transition -translate-x-full opacity-0 focus:translate-x-0 focus:opacity-100" href="#content">
Skip to content
</a><header class="sticky top-0 z-40 w-full border-b shadow-xs border-border bg-background/90 backdrop-blur"><div class="container flex items-center h-14">
<div class="hidden mr-4 md:flex">
<a class="flex items-center mr-6" href="../index.html">
<img alt="Logo" class="mr-2 dark:invert" height="24" src="../_static/favicon.ico" width="24"/><span class="hidden font-bold sm:inline-block text-clip whitespace-nowrap">Plano Docs v0.4.19</span>
</a></div><button @click="showSidebar = true" class="inline-flex items-center justify-center h-10 px-0 py-2 mr-2 text-base font-medium transition-colors rounded-md hover:text-accent-foreground hover:bg-transparent md:hidden" type="button">
<svg aria-hidden="true" fill="currentColor" height="24" viewbox="0 96 960 960" width="24" xmlns="http://www.w3.org/2000/svg">
<path d="M152.587 825.087q-19.152 0-32.326-13.174t-13.174-32.326q0-19.152 13.174-32.326t32.326-13.174h440q19.152 0 32.326 13.174t13.174 32.326q0 19.152-13.174 32.326t-32.326 13.174h-440Zm0-203.587q-19.152 0-32.326-13.174T107.087 576q0-19.152 13.174-32.326t32.326-13.174h320q19.152 0 32.326 13.174T518.087 576q0 19.152-13.174 32.326T472.587 621.5h-320Zm0-203.587q-19.152 0-32.326-13.174t-13.174-32.326q0-19.152 13.174-32.326t32.326-13.174h440q19.152 0 32.326 13.174t13.174 32.326q0 19.152-13.174 32.326t-32.326 13.174h-440ZM708.913 576l112.174 112.174q12.674 12.674 12.674 31.826t-12.674 31.826Q808.413 764.5 789.261 764.5t-31.826-12.674l-144-144Q600 594.391 600 576t13.435-31.826l144-144q12.674-12.674 31.826-12.674t31.826 12.674q12.674 12.674 12.674 31.826t-12.674 31.826L708.913 576Z"></path>
</svg>
<span class="sr-only">Toggle navigation menu</span>
</button>
<div class="flex items-center justify-between flex-1 gap-2 sm:gap-4 md:justify-end">
<div class="flex-1 w-full md:w-auto md:flex-none"><form @keydown.k.window.meta="$refs.search.focus()" action="../search.html" class="relative flex items-center group" id="searchbox" method="get">
<input aria-label="Search the docs" class="inline-flex items-center font-medium transition-colors bg-transparent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 ring-offset-background border border-input hover:bg-accent focus:bg-accent hover:text-accent-foreground focus:text-accent-foreground hover:placeholder-accent-foreground py-2 px-4 relative h-9 w-full justify-start rounded-[0.5rem] text-sm text-muted-foreground sm:pr-12 md:w-40 lg:w-64" id="search-input" name="q" placeholder="Search ..." type="search" x-ref="search"/>
<kbd class="pointer-events-none absolute right-1.5 top-2 hidden h-5 select-none text-muted-foreground items-center gap-1 rounded border border-border bg-muted px-1.5 font-mono text-[10px] font-medium opacity-100 sm:flex group-hover:bg-accent group-hover:text-accent-foreground">
<span class="text-xs">⌘</span>
K
</kbd>
</form>
</div>
<nav class="flex items-center gap-1">
<a href="https://github.com/katanemo/plano" rel="noopener nofollow" title="Visit repository on GitHub">
<div class="inline-flex items-center justify-center px-0 text-sm font-medium transition-colors rounded-md hover:bg-accent hover:text-accent-foreground h-9 w-9">
<svg fill="currentColor" height="26px" style="margin-top:-2px;display:inline" viewbox="0 0 45 44" xmlns="http://www.w3.org/2000/svg"><path clip-rule="evenodd" d="M22.477.927C10.485.927.76 10.65.76 22.647c0 9.596 6.223 17.736 14.853 20.608 1.087.2 1.483-.47 1.483-1.047 0-.516-.019-1.881-.03-3.693-6.04 1.312-7.315-2.912-7.315-2.912-.988-2.51-2.412-3.178-2.412-3.178-1.972-1.346.149-1.32.149-1.32 2.18.154 3.327 2.24 3.327 2.24 1.937 3.318 5.084 2.36 6.321 1.803.197-1.403.759-2.36 1.379-2.903-4.823-.548-9.894-2.412-9.894-10.734 0-2.37.847-4.31 2.236-5.828-.224-.55-.969-2.759.214-5.748 0 0 1.822-.584 5.972 2.226 1.732-.482 3.59-.722 5.437-.732 1.845.01 3.703.25 5.437.732 4.147-2.81 5.967-2.226 5.967-2.226 1.185 2.99.44 5.198.217 5.748 1.392 1.517 2.232 3.457 2.232 5.828 0 8.344-5.078 10.18-9.916 10.717.779.67 1.474 1.996 1.474 4.021 0 2.904-.027 5.247-.027 5.96 0 .58.392 1.256 1.493 1.044C37.981 40.375 44.2 32.24 44.2 22.647c0-11.996-9.726-21.72-21.722-21.72" fill="currentColor" fill-rule="evenodd"></path></svg>
</div>
</a>
<button @click="darkMode = !darkMode" class="relative inline-flex items-center justify-center px-0 text-sm font-medium transition-colors rounded-md hover:bg-accent hover:text-accent-foreground h-9 w-9" title="Toggle color scheme" type="button">
<svg class="absolute transition-all scale-100 rotate-0 dark:-rotate-90 dark:scale-0" fill="currentColor" height="16" viewbox="0 96 960 960" width="16" xmlns="http://www.w3.org/2000/svg">
<path d="M480 685q45.456 0 77.228-31.772Q589 621.456 589 576q0-45.456-31.772-77.228Q525.456 467 480 467q-45.456 0-77.228 31.772Q371 530.544 371 576q0 45.456 31.772 77.228Q434.544 685 480 685Zm0 91q-83 0-141.5-58.5T280 576q0-83 58.5-141.5T480 376q83 0 141.5 58.5T680 576q0 83-58.5 141.5T480 776ZM80 621.5q-19.152 0-32.326-13.174T34.5 576q0-19.152 13.174-32.326T80 530.5h80q19.152 0 32.326 13.174T205.5 576q0 19.152-13.174 32.326T160 621.5H80Zm720 0q-19.152 0-32.326-13.174T754.5 576q0-19.152 13.174-32.326T800 530.5h80q19.152 0 32.326 13.174T925.5 576q0 19.152-13.174 32.326T880 621.5h-80Zm-320-320q-19.152 0-32.326-13.174T434.5 256v-80q0-19.152 13.174-32.326T480 130.5q19.152 0 32.326 13.174T525.5 176v80q0 19.152-13.174 32.326T480 301.5Zm0 720q-19.152 0-32.326-13.17Q434.5 995.152 434.5 976v-80q0-19.152 13.174-32.326T480 850.5q19.152 0 32.326 13.174T525.5 896v80q0 19.152-13.174 32.33-13.174 13.17-32.326 13.17ZM222.174 382.065l-43-42Q165.5 327.391 166 308.239t13.174-33.065q13.435-13.674 32.587-13.674t32.065 13.674l42.239 43q12.674 13.435 12.555 31.706-.12 18.272-12.555 31.946-12.674 13.674-31.445 13.413-18.772-.261-32.446-13.174Zm494 494.761-42.239-43q-12.674-13.435-12.674-32.087t12.674-31.565Q686.609 756.5 705.38 757q18.772.5 32.446 13.174l43 41.761Q794.5 824.609 794 843.761t-13.174 33.065Q767.391 890.5 748.239 890.5t-32.065-13.674Zm-42-494.761Q660.5 369.391 661 350.62q.5-18.772 13.174-32.446l41.761-43Q728.609 261.5 747.761 262t33.065 13.174q13.674 13.435 13.674 32.587t-13.674 32.065l-43 42.239q-13.435 12.674-31.706 12.555-18.272-.12-31.946-12.555Zm-495 494.761Q165.5 863.391 165.5 844.239t13.674-32.065l43-42.239q13.435-12.674 32.087-12.674t31.565 12.674Q299.5 782.609 299 801.38q-.5 18.772-13.174 32.446l-41.761 43Q231.391 890.5 212.239 890t-33.065-13.174ZM480 576Z"></path>
</svg>
<svg class="absolute transition-all scale-0 rotate-90 dark:rotate-0 dark:scale-100" fill="currentColor" height="16" viewbox="0 96 960 960" width="16" xmlns="http://www.w3.org/2000/svg">
<path d="M480 936q-151 0-255.5-104.5T120 576q0-138 90-239.5T440 218q25-3 39 18t-1 44q-17 26-25.5 55t-8.5 61q0 90 63 153t153 63q31 0 61.5-9t54.5-25q21-14 43-1.5t19 39.5q-14 138-117.5 229T480 936Zm0-80q88 0 158-48.5T740 681q-20 5-40 8t-40 3q-123 0-209.5-86.5T364 396q0-20 3-40t8-40q-78 32-126.5 102T200 576q0 116 82 198t198 82Zm-10-270Z"></path>
</svg>
</button>
</nav>
</div>
</div>
</header>
<div class="flex-1"><div class="container md:grid md:grid-cols-[220px_minmax(0,1fr)] md:gap-6 lg:grid-cols-[240px_minmax(0,1fr)] lg:gap-10"><aside :aria-hidden="!showSidebar" :class="{ 'translate-x-0': showSidebar }" class="fixed inset-y-0 left-0 md:top-14 z-50 md:z-30 bg-background md:bg-transparent transition-all duration-100 -translate-x-full md:translate-x-0 ml-0 p-6 md:p-0 md:-ml-2 md:h-[calc(100vh-3.5rem)] w-5/6 md:w-full overflow-y-auto border-r border-border md:sticky" id="left-sidebar">
<a class="justify-start text-sm md:!hidden bg-background" href="../index.html">
<img alt="Logo" class="mr-2 dark:invert" height="16" src="../_static/favicon.ico" width="16"/><span class="font-bold text-clip whitespace-nowrap">Plano Docs v0.4.19</span>
</a>
<div class="relative overflow-hidden md:overflow-auto my-4 md:my-0">
<div class="overflow-y-auto h-full w-full relative pr-6">
<script async="" src="https://www.googletagmanager.com/gtag/js?id=G-EH2VW19FXE"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'G-EH2VW19FXE');
</script>
<nav class="table w-full min-w-full my-6 lg:my-8">
<p class="caption" role="heading"><span class="caption-text">Get Started</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../get_started/overview.html">Overview</a></li>
<li class="toctree-l1"><a class="reference internal" href="../get_started/intro_to_plano.html">Intro to Plano</a></li>
<li class="toctree-l1"><a class="reference internal" href="../get_started/quickstart.html">Quickstart</a></li>
<li class="toctree-l1"><a class="reference internal" href="../get_started/quickstart.html#next-steps">Next Steps</a></li>
</ul>
<p class="caption" role="heading"><span class="caption-text">Concepts</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../concepts/listeners.html">Listeners</a></li>
<li class="toctree-l1"><a class="reference internal" href="../concepts/agents.html">Agents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../concepts/filter_chain.html">Filter Chains</a></li>
<li class="toctree-l1" x-data="{ expanded: $el.classList.contains('current') ? true : false }"><a :class="{ 'expanded' : expanded }" @click="expanded = !expanded" class="reference internal expandable" href="../concepts/llm_providers/llm_providers.html">Model (LLM) Providers<button @click.prevent.stop="expanded = !expanded" type="button" x-cloak=""><span class="sr-only"></span><svg fill="currentColor" height="18px" stroke="none" viewbox="0 0 24 24" width="18px" xmlns="http://www.w3.org/2000/svg"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></svg></button></a><ul x-cloak="" x-show="expanded">
<li class="toctree-l2"><a class="reference internal" href="../concepts/llm_providers/supported_providers.html">Supported Providers &amp; Configuration</a></li>
<li class="toctree-l2"><a class="reference internal" href="../concepts/llm_providers/client_libraries.html">Client Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../concepts/llm_providers/model_aliases.html">Model Aliases</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../concepts/prompt_target.html">Prompt Target</a></li>
<li class="toctree-l1"><a class="reference internal" href="../concepts/signals.html">Signals™</a></li>
</ul>
<p class="caption" role="heading"><span class="caption-text">Guides</span></p>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="orchestration.html">Orchestration</a></li>
<li class="toctree-l1"><a class="reference internal" href="llm_router.html">LLM Routing</a></li>
<li class="toctree-l1"><a class="reference internal" href="function_calling.html">Function Calling</a></li>
<li class="toctree-l1" x-data="{ expanded: $el.classList.contains('current') ? true : false }"><a :class="{ 'expanded' : expanded }" @click="expanded = !expanded" class="reference internal expandable" href="observability/observability.html">Observability<button @click.prevent.stop="expanded = !expanded" type="button" x-cloak=""><span class="sr-only"></span><svg fill="currentColor" height="18px" stroke="none" viewbox="0 0 24 24" width="18px" xmlns="http://www.w3.org/2000/svg"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></svg></button></a><ul x-cloak="" x-show="expanded">
<li class="toctree-l2"><a class="reference internal" href="observability/tracing.html">Tracing</a></li>
<li class="toctree-l2"><a class="reference internal" href="observability/monitoring.html">Monitoring</a></li>
<li class="toctree-l2"><a class="reference internal" href="observability/access_logging.html">Access Logging</a></li>
</ul>
</li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">Guardrails</a></li>
<li class="toctree-l1"><a class="reference internal" href="state.html">Conversational State</a></li>
</ul>
<p class="caption" role="heading"><span class="caption-text">Resources</span></p>
<ul>
<li class="toctree-l1" x-data="{ expanded: $el.classList.contains('current') ? true : false }"><a :class="{ 'expanded' : expanded }" @click="expanded = !expanded" class="reference internal expandable" href="../resources/tech_overview/tech_overview.html">Tech Overview<button @click.prevent.stop="expanded = !expanded" type="button" x-cloak=""><span class="sr-only"></span><svg fill="currentColor" height="18px" stroke="none" viewbox="0 0 24 24" width="18px" xmlns="http://www.w3.org/2000/svg"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></svg></button></a><ul x-cloak="" x-show="expanded">
<li class="toctree-l2"><a class="reference internal" href="../resources/tech_overview/request_lifecycle.html">Request Lifecycle</a></li>
<li class="toctree-l2"><a class="reference internal" href="../resources/tech_overview/model_serving.html">Bright Staff</a></li>
<li class="toctree-l2"><a class="reference internal" href="../resources/tech_overview/threading_model.html">Threading Model</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../resources/deployment.html">Deployment</a></li>
<li class="toctree-l1"><a class="reference internal" href="../resources/configuration_reference.html">Configuration Reference</a></li>
<li class="toctree-l1"><a class="reference internal" href="../resources/cli_reference.html">CLI Reference</a></li>
<li class="toctree-l1"><a class="reference internal" href="../resources/llms_txt.html">llms.txt</a></li>
</ul>
</nav>
</div>
</div>
<button @click="showSidebar = false" class="absolute md:hidden right-4 top-4 rounded-sm opacity-70 transition-opacity hover:opacity-100" type="button">
<svg class="h-4 w-4" fill="currentColor" height="24" stroke="none" viewbox="0 96 960 960" width="24" xmlns="http://www.w3.org/2000/svg">
<path d="M480 632 284 828q-11 11-28 11t-28-11q-11-11-11-28t11-28l196-196-196-196q-11-11-11-28t11-28q11-11 28-11t28 11l196 196 196-196q11-11 28-11t28 11q11 11 11 28t-11 28L536 576l196 196q11 11 11 28t-11 28q-11 11-28 11t-28-11L480 632Z"></path>
</svg>
</button>
</aside>
<main class="relative py-6 lg:gap-10 lg:py-8 xl:grid xl:grid-cols-[1fr_300px]">
<div class="w-full min-w-0 mx-auto">
<nav aria-label="breadcrumbs" class="flex items-center mb-4 space-x-1 text-sm text-muted-foreground">
<a class="overflow-hidden text-ellipsis whitespace-nowrap hover:text-foreground" href="../index.html">
<span class="hidden md:inline">Plano Docs v0.4.19</span>
<svg aria-label="Home" class="md:hidden" fill="currentColor" height="18" stroke="none" viewbox="0 96 960 960" width="18" xmlns="http://www.w3.org/2000/svg">
<path d="M240 856h120V616h240v240h120V496L480 316 240 496v360Zm-80 80V456l320-240 320 240v480H520V696h-80v240H160Zm320-350Z"></path>
</svg>
</a>
<div class="mr-1">/</div><span aria-current="page" class="font-medium text-foreground overflow-hidden text-ellipsis whitespace-nowrap">Guardrails</span>
</nav>
<div id="content" role="main">
<section id="guardrails">
<span id="prompt-guard"></span><h1>Guardrails<a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#guardrails"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></h1>
<p><strong>Guardrails</strong> are Plano’s way of applying safety and validation checks to prompts before they reach your application logic. They are typically implemented as
filters in a <a class="reference internal" href="../concepts/filter_chain.html#filter-chain"><span class="std std-ref">Filter Chain</span></a> attached to an agent, so every request passes through a consistent processing layer.</p>
<section id="why-guardrails">
<h2>Why Guardrails<a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#why-guardrails" x-intersect.margin.0%.0%.-70%.0%="activeSection = '#why-guardrails'"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></h2>
<p>Guardrails are essential for maintaining control over AI-driven applications. They help enforce organizational policies, ensure compliance with regulations
(like GDPR or HIPAA), and protect users from harmful or inappropriate content. In applications where prompts generate responses or trigger actions, guardrails
minimize risks like malicious inputs, off-topic queries, or misaligned outputs—adding a consistent layer of input scrutiny that makes interactions safer,
more reliable, and easier to reason about.</p>
<ul class="simple">
<li><p><strong>Jailbreak Prevention</strong>: Detect and filter inputs that attempt to change LLM behavior, expose system prompts, or bypass safety policies.</p></li>
<li><p><strong>Domain and Topicality Enforcement</strong>: Ensure that agents only respond to prompts within an approved domain (for example, finance-only or healthcare-only use cases) and reject unrelated queries.</p></li>
<li><p><strong>Dynamic Error Handling</strong>: Provide clear error messages when requests violate policy, helping users correct their inputs.</p></li>
</ul>
</section>
<section id="how-guardrails-work">
<h2>How Guardrails Work<a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#how-guardrails-work" x-intersect.margin.0%.0%.-70%.0%="activeSection = '#how-guardrails-work'"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></h2>
<p>Guardrails can be implemented as either in-process MCP filters or as HTTP-based filters. HTTP filters are external services that receive the request over HTTP, validate it, and return a response to allow or reject the request. This makes it easy to use filters written in any language or run them as independent services.</p>
<p>Each filter receives the chat messages, evaluates them against policy, and either lets the request continue or raises a <code class="docutils literal notranslate"><span class="pre">ToolError</span></code> (or returns an error response) to reject it with a helpful error message.</p>
<p>The example below shows an input guard for TechCorp’s customer support system that validates queries are within the company’s domain:</p>
<div class="literal-block-wrapper docutils container" id="id1">
<div class="code-block-caption"><span class="caption-text">Example domain validation guard using FastMCP</span><a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#id1"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></div>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><code><span id="line-1"><span class="kn">from</span><span class="w"> </span><span class="nn">typing</span><span class="w"> </span><span class="kn">import</span> <span class="n">List</span>
</span><span id="line-2"><span class="kn">from</span><span class="w"> </span><span class="nn">fastmcp.exceptions</span><span class="w"> </span><span class="kn">import</span> <span class="n">ToolError</span>
</span><span id="line-3"><span class="kn">from</span><span class="w"> </span><span class="nn">.</span><span class="w"> </span><span class="kn">import</span> <span class="n">mcp</span>
</span><span id="line-4">
</span><span id="line-5"><span class="nd">@mcp</span><span class="o">.</span><span class="n">tool</span>
</span><span id="line-6"><span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">input_guards</span><span class="p">(</span><span class="n">messages</span><span class="p">:</span> <span class="n">List</span><span class="p">[</span><span class="n">ChatMessage</span><span class="p">])</span> <span class="o">-&gt;</span> <span class="n">List</span><span class="p">[</span><span class="n">ChatMessage</span><span class="p">]:</span>
</span><span id="line-7"><span class="w"> </span><span class="sd">"""Validates queries are within TechCorp's domain."""</span>
</span><span id="line-8">
</span><span id="line-9"> <span class="c1"># Get the user's query</span>
</span><span id="line-10"> <span class="n">user_query</span> <span class="o">=</span> <span class="nb">next</span><span class="p">(</span>
</span><span id="line-11"> <span class="p">(</span><span class="n">msg</span><span class="o">.</span><span class="n">content</span> <span class="k">for</span> <span class="n">msg</span> <span class="ow">in</span> <span class="nb">reversed</span><span class="p">(</span><span class="n">messages</span><span class="p">)</span> <span class="k">if</span> <span class="n">msg</span><span class="o">.</span><span class="n">role</span> <span class="o">==</span> <span class="s2">"user"</span><span class="p">),</span>
</span><span id="line-12"> <span class="s2">""</span>
</span><span id="line-13"> <span class="p">)</span>
</span><span id="line-14">
</span><span id="line-15"> <span class="c1"># Use an LLM to validate the query scope (simplified)</span>
</span><span id="line-16"> <span class="n">is_valid</span> <span class="o">=</span> <span class="k">await</span> <span class="n">validate_with_llm</span><span class="p">(</span><span class="n">user_query</span><span class="p">)</span>
</span><span id="line-17">
</span><span id="line-18"> <span class="k">if</span> <span class="ow">not</span> <span class="n">is_valid</span><span class="p">:</span>
</span><span id="line-19"> <span class="k">raise</span> <span class="n">ToolError</span><span class="p">(</span>
</span><span id="line-20"> <span class="s2">"I can only assist with questions related to TechCorp and its services. "</span>
</span><span id="line-21"> <span class="s2">"Please ask about TechCorp's products, pricing, SLAs, or technical support."</span>
</span><span id="line-22"> <span class="p">)</span>
</span><span id="line-23">
</span><span id="line-24"> <span class="k">return</span> <span class="n">messages</span>
</span></code></pre></div>
</div>
</div>
<p>To wire this guardrail into Plano, define the filter and add it to your agent’s filter chain:</p>
<div class="literal-block-wrapper docutils container" id="id2">
<div class="code-block-caption"><span class="caption-text">Plano configuration with input guard filter</span><a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#id2"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></div>
<div class="highlight-yaml notranslate"><div class="highlight"><pre><span></span><code><span id="line-1"><span class="nt">filters</span><span class="p">:</span>
</span><span id="line-2"><span class="w"> </span><span class="p p-Indicator">-</span><span class="w"> </span><span class="nt">id</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">input_guards</span>
</span><span id="line-3"><span class="w"> </span><span class="nt">url</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">http://localhost:10500</span>
</span><span id="line-4">
</span><span id="line-5"><span class="nt">listeners</span><span class="p">:</span>
</span><span id="line-6"><span class="w"> </span><span class="p p-Indicator">-</span><span class="w"> </span><span class="nt">type</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">agent</span>
</span><span id="line-7"><span class="w"> </span><span class="nt">name</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">agent_1</span>
</span><span id="line-8"><span class="w"> </span><span class="nt">port</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">8001</span>
</span><span id="line-9"><span class="w"> </span><span class="nt">router</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">plano_orchestrator_v1</span>
</span><span id="line-10"><span class="w"> </span><span class="nt">agents</span><span class="p">:</span>
</span><span id="line-11"><span class="w"> </span><span class="p p-Indicator">-</span><span class="w"> </span><span class="nt">id</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">rag_agent</span>
</span><span id="line-12"><span class="w"> </span><span class="nt">description</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">virtual assistant for retrieval augmented generation tasks</span>
</span><span id="line-13"><span class="w"> </span><span class="nt">filter_chain</span><span class="p">:</span>
</span><span id="line-14"><span class="w"> </span><span class="p p-Indicator">-</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">input_guards</span>
</span></code></pre></div>
</div>
</div>
<p>When a request arrives at <code class="docutils literal notranslate"><span class="pre">agent_1</span></code>, Plano invokes the <code class="docutils literal notranslate"><span class="pre">input_guards</span></code> filter first. If validation passes, the request continues to
the agent. If validation fails (<code class="docutils literal notranslate"><span class="pre">ToolError</span></code> raised), Plano returns an error response to the caller.</p>
</section>
<section id="testing-the-guardrail">
<h2>Testing the Guardrail<a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#testing-the-guardrail" x-intersect.margin.0%.0%.-70%.0%="activeSection = '#testing-the-guardrail'"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></h2>
<p>Here’s an example of the guardrail in action, rejecting a query about Apple Corporation (outside TechCorp’s domain):</p>
<div class="literal-block-wrapper docutils container" id="id3">
<div class="code-block-caption"><span class="caption-text">Request that violates the guardrail policy</span><a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#id3"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></div>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span><code><span id="line-1">curl<span class="w"> </span>-X<span class="w"> </span>POST<span class="w"> </span>http://localhost:8001/v1/chat/completions<span class="w"> </span><span class="se">\</span>
</span><span id="line-2"><span class="w"> </span>-H<span class="w"> </span><span class="s2">"Content-Type: application/json"</span><span class="w"> </span><span class="se">\</span>
</span><span id="line-3"><span class="w"> </span>-d<span class="w"> </span><span class="s1">'{</span>
</span><span id="line-4"><span class="s1"> "model": "gpt-4",</span>
</span><span id="line-5"><span class="s1"> "messages": [</span>
</span><span id="line-6"><span class="s1"> {</span>
</span><span id="line-7"><span class="s1"> "role": "user",</span>
</span><span id="line-8"><span class="s1"> "content": "what is sla for apple corporation?"</span>
</span><span id="line-9"><span class="s1"> }</span>
</span><span id="line-10"><span class="s1"> ],</span>
</span><span id="line-11"><span class="s1"> "stream": false</span>
</span><span id="line-12"><span class="s1"> }'</span>
</span></code></pre></div>
</div>
</div>
<div class="literal-block-wrapper docutils container" id="id4">
<div class="code-block-caption"><span class="caption-text">Error response from the guardrail</span><a @click.prevent="window.navigator.clipboard.writeText($el.href); $el.setAttribute('data-tooltip', 'Copied!'); setTimeout(() =&gt; $el.setAttribute('data-tooltip', 'Copy link to this element'), 2000)" aria-label="Copy link to this element" class="headerlink" data-tooltip="Copy link to this element" href="#id4"><svg height="1em" viewbox="0 0 24 24" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"></path></svg></a></div>
<div class="highlight-json notranslate"><div class="highlight"><pre><span></span><code><span id="line-1"><span class="p">{</span>
</span><span id="line-2"><span class="w"> </span><span class="nt">"error"</span><span class="p">:</span><span class="w"> </span><span class="s2">"ClientError"</span><span class="p">,</span>
</span><span id="line-3"><span class="w"> </span><span class="nt">"agent"</span><span class="p">:</span><span class="w"> </span><span class="s2">"input_guards"</span><span class="p">,</span>
</span><span id="line-4"><span class="w"> </span><span class="nt">"status"</span><span class="p">:</span><span class="w"> </span><span class="mi">400</span><span class="p">,</span>
</span><span id="line-5"><span class="w"> </span><span class="nt">"agent_response"</span><span class="p">:</span><span class="w"> </span><span class="s2">"I apologize, but I can only assist with questions related to TechCorp and its services. Your query appears to be outside this scope. The query is about SLA for Apple Corporation, which is unrelated to TechCorp.\n\nPlease ask me about TechCorp's products, services, pricing, SLAs, or technical support."</span>
</span><span id="line-6"><span class="p">}</span>
</span></code></pre></div>
</div>
</div>
<p>This prevents out-of-scope queries from reaching your agent while providing clear feedback to users about why their request was rejected.</p>
</section>
</section>
</div><div class="flex justify-between items-center pt-6 mt-12 border-t border-border gap-4">
<div class="mr-auto">
<a class="inline-flex items-center justify-center rounded-md text-sm font-medium transition-colors border border-input hover:bg-accent hover:text-accent-foreground py-2 px-4" href="observability/access_logging.html">
<svg class="mr-2 h-4 w-4" fill="none" height="24" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" viewbox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg">
<polyline points="15 18 9 12 15 6"></polyline>
</svg>
Access Logging
</a>
</div>
<div class="ml-auto">
<a class="inline-flex items-center justify-center rounded-md text-sm font-medium transition-colors border border-input hover:bg-accent hover:text-accent-foreground py-2 px-4" href="state.html">
Conversational State
<svg class="ml-2 h-4 w-4" fill="none" height="24" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" viewbox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg">
<polyline points="9 18 15 12 9 6"></polyline>
</svg>
</a>
</div>
</div></div><aside class="hidden text-sm xl:block" id="right-sidebar">
<div class="sticky top-16 -mt-10 max-h-[calc(100vh-5rem)] h-full overflow-y-auto pt-6 space-y-2"><p class="font-medium">On this page</p>
<ul>
<li><a :data-current="activeSection === '#why-guardrails'" class="reference internal" href="#why-guardrails">Why Guardrails</a></li>
<li><a :data-current="activeSection === '#how-guardrails-work'" class="reference internal" href="#how-guardrails-work">How Guardrails Work</a></li>
<li><a :data-current="activeSection === '#testing-the-guardrail'" class="reference internal" href="#testing-the-guardrail">Testing the Guardrail</a></li>
</ul>
</div>
</aside>
</main>
</div>
</div><footer class="py-6 border-t border-border md:py-0">
<div class="container flex flex-col items-center justify-between gap-4 md:h-24 md:flex-row">
<div class="flex flex-col items-center gap-4 px-8 md:flex-row md:gap-2 md:px-0">
<p class="text-sm leading-loose text-center text-muted-foreground md:text-left">© 2026, Katanemo Labs, a DigitalOcean Company Last updated: Apr 18, 2026. </p>
</div>
</div>
</footer>
</div>
<script src="../_static/documentation_options.js?v=0bdd1eca"></script>
<script src="../_static/doctools.js?v=9bcbadda"></script>
<script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
<script defer="defer" src="../_static/theme.js?v=d6a9845b"></script>
<script src="../_static/design-tabs.js?v=f930bc37"></script>
<script src="../_static/js/fix-copy.js?v=2f5cab98"></script>
</body>
</html>
Reference in a new issue View git blame Copy permalink