IntersectMBO · Unisay · Aug 28, 2026 · Aug 25, 2026 · Aug 26, 2026
diff --git a/doc/cost-models/policies/index.html b/doc/cost-models/policies/index.html
@@ -0,0 +1,118 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>Policies - Plutus Cost Model Visualization</title>
+  <link rel="stylesheet" href="../shared/styles.css">
+  <script src="https://cdn.plot.ly/plotly-2.27.0.min.js"></script>
+</head>
+<body>
+  <nav></nav>
+
+  <div class="container">
+    <h1>Policies Cost Model Visualization</h1>
+    <p>
+      Interactive visualization of benchmark data and fitted cost model for the <code>Policies</code> builtin function.
+      This function returns the currency symbols of a <code>Value</code> in ascending order.
+    </p>
+
+    <div class="controls" id="data-source-controls">
+      <h3 id="data-source-toggle">Data Source Configuration</h3>
+      <div class="controls-content">
+        <div class="control-group-vertical">
+          <label for="branch-name">Branch name:</label>
+          <div class="branch-input-row">
+            <input type="text" id="branch-name" placeholder="master">
+            <button id="copy-link" title="Copy shareable link">Copy Link</button>
+          </div>
+        </div>
+        <div class="control-group-vertical">
+          <label for="csv-url">CSV file URL:</label>
+          <input type="text" id="csv-url" style="width: 100%; font-family: monospace;">
+        </div>
+        <div class="control-group-vertical">
+          <label for="json-url">JSON file URL:</label>
+          <input type="text" id="json-url" style="width: 100%; font-family: monospace;">
+        </div>
+        <div class="control-group">
+          <button id="reload-data">Load Data</button>
+        </div>
+      </div>
+    </div>
+
+    <div class="controls" id="plot-controls">
+      <h3 id="plot-controls-toggle">Plot Controls</h3>
+      <div class="controls-content">
+        <div class="control-group">
+          <input type="checkbox" id="show-model" checked>
+          <label for="show-model">Show model predictions</label>
+        </div>
+        <div class="control-group">
+          <label for="y-axis-mode">Y-axis range:</label>
+          <select id="y-axis-mode">
+            <option value="zero">Start from 0</option>
+            <option value="auto">Auto-scale from min</option>
+          </select>
+        </div>
+      </div>
+    </div>
+
+    <div class="plot-wrapper">
+      <div id="plot-container">
+        <div class="loading">Loading data and generating plot...</div>
+      </div>
+
+      <div class="info-panel">
+        <h3>Plot Information</h3>
+
+        <div class="info-section">
+          <dl>
+            <dt>X-axis:</dt>
+            <dd id="info-x-axis">Value Size</dd>
+
+            <dt>Y-axis:</dt>
+            <dd id="info-y-axis">Time (nanoseconds)</dd>
+
+            <dt>Description:</dt>
+            <dd id="info-description">Each point represents one benchmark run</dd>
+          </dl>
+        </div>
+
+        <div class="info-section">
+          <dt>Cost Model Type:</dt>
+          <dd id="info-model-type">Loading...</dd>
+
+          <dt>Model Formula (net):</dt>
+          <dd class="formula" id="info-model-formula">Loading...</dd>
+
+          <dt>Overhead:</dt>
+          <dd id="info-overhead">Loading...</dd>
+        </div>
+
+        <div class="info-section">
+          <dl>
+            <dt>Data points:</dt>
+            <dd id="info-data-points">-</dd>
+
+            <dt>Value Size range:</dt>
+            <dd id="info-x-range">-</dd>
+
+            <dt>Time range:</dt>
+            <dd id="info-time-range">-</dd>
+          </dl>
+        </div>
+
+        <div class="info-section">
+          <dl id="info-data-sources"></dl>
+        </div>
+      </div>
+    </div>
+  </div>
+
+  <footer></footer>
+
+  <script src="../shared/utils.js"></script>
+  <script src="plot.js"></script>
+</body>
+</html>
diff --git a/doc/cost-models/policies/plot.js b/doc/cost-models/policies/plot.js
@@ -0,0 +1,171 @@
+// Policies plot configuration and rendering
+
+// Configuration
+const FUNCTION_NAME = 'Policies';  // CSV uses PascalCase
+const COST_MODEL_NAME = 'policies';  // JSON uses camelCase
+const ARITY = 1;
+
+// Global state
+let benchmarkData = [];
+let modelPredictions = [];
+let costModel = null;
+let overhead = 0;
+let showModel = true;
+let yAxisMode = 'zero';
+
+setupCostModelPage({
+  slug: 'policies',
+  functionName: FUNCTION_NAME,
+  costModelName: COST_MODEL_NAME,
+  arity: ARITY,
+  render(data) {
+    ({ benchmarkData, costModel, overhead, modelPredictions } = data);
+    updateInfoPanel();
+    renderPlot();
+  },
+  setupControls
+});
+
+function updateInfoPanel() {
+  // Calculate stats
+  const stats = calculateStats(benchmarkData, 0);
+
+  // Update data points
+  document.getElementById('info-data-points').textContent = stats.dataPoints;
+
+  // Update ranges
+  if (stats.minArg !== undefined) {
+    document.getElementById('info-x-range').textContent = `${stats.minArg} - ${stats.maxArg}`;
+  }
+
+  document.getElementById('info-time-range').textContent = stats.timeRange;
+
+  // Update model info
+  if (costModel) {
+    document.getElementById('info-model-type').textContent = costModel.modelType;
+    document.getElementById('info-model-formula').textContent = formatModelFormula(
+      costModel.modelType,
+      costModel.coefficients
+    );
+  } else {
+    document.getElementById('info-model-type').textContent = 'Not available';
+    document.getElementById('info-model-formula').textContent = 'Cost model not found';
+  }
+
+  // Update overhead
+  if (overhead > 0) {
+    document.getElementById('info-overhead').textContent =
+      `${overhead.toFixed(2)} ns (arity ${ARITY}) added to predictions`;
+  } else {
+    document.getElementById('info-overhead').textContent = 'Not calculated';
+  }
+}
+
+function renderPlot() {
+  // Prepare benchmark trace
+  const benchmarkX = benchmarkData.map(d => d.args[0]);
+  const benchmarkY = benchmarkData.map(d => d.time);
+
+  const benchmarkTrace = {
+    x: benchmarkX,
+    y: benchmarkY,
+    mode: 'markers',
+    type: 'scatter',
+    name: 'Benchmark Data',
+    marker: {
+      size: 6,
+      color: '#0033AD',
+      opacity: 0.7
+    }
+  };
+
+  const traces = [benchmarkTrace];
+
+  // Prepare model trace if available
+  if (showModel && modelPredictions.length > 0) {
+    const modelX = modelPredictions.map(d => d.args[0]);
+    const modelY = modelPredictions.map(d => d.predictedTime);
+
+    const modelTrace = {
+      x: modelX,
+      y: modelY,
+      mode: 'markers',
+      type: 'scatter',
+      name: 'Model Predictions',
+      marker: {
+        size: 6,
+        color: '#E53E3E',
+        opacity: 0.4,
+        symbol: 'x'
+      }
+    };
+
+    traces.push(modelTrace);
+  }
+
+  // Layout configuration
+  const layout = {
+    title: {
+      text: `${FUNCTION_NAME} - Benchmark vs Model`,
+      font: { size: 20 }
+    },
+    xaxis: {
+      title: 'Value Size',
+      gridcolor: '#E0E0E0'
+    },
+    yaxis: {
+      title: 'Time (nanoseconds)',
+      gridcolor: '#E0E0E0'
+    },
+    hovermode: 'closest',
+    showlegend: true,
+    legend: {
+      x: 0.02,
+      y: 0.98,
+      bgcolor: 'rgba(255, 255, 255, 0.8)',
+      bordercolor: '#BDC3C7',
+      borderwidth: 1
+    },
+    plot_bgcolor: '#FAFAFA',
+    paper_bgcolor: 'rgba(0,0,0,0)'
+  };
+
+  // Set Y-axis range based on mode
+  if (yAxisMode === 'zero') {
+    layout.yaxis.range = [0, Math.max(...benchmarkY) * 1.1];
+  } else {
+    const minY = Math.min(...benchmarkY);
+    const maxY = Math.max(...benchmarkY);
+    const padding = (maxY - minY) * 0.1;
+    layout.yaxis.range = [minY - padding, maxY + padding];
+  }
+
+  // Config
+  const config = {
+    responsive: true,
+    displayModeBar: true,
+    displaylogo: false
+  };
+
+  // Render
+  // Clear loading message
+  const container = document.getElementById('plot-container');
+  container.innerHTML = '';
+  Plotly.newPlot('plot-container', traces, layout, config);
+}
+
+function setupControls() {
+  // Show/hide model checkbox
+  const showModelCheckbox = document.getElementById('show-model');
+  showModelCheckbox.addEventListener('change', (e) => {
+    showModel = e.target.checked;
+    renderPlot();
+  });
+
+  // Y-axis mode selector
+  const yAxisModeSelect = document.getElementById('y-axis-mode');
+  yAxisModeSelect.addEventListener('change', (e) => {
+    yAxisMode = e.target.value;
+    renderPlot();
+  });
+}
diff --git a/doc/cost-models/shared/utils.js b/doc/cost-models/shared/utils.js
@@ -525,6 +525,9 @@ const PAGES = [
    'Returns the number of <code>(currency symbol, token name)</code> pairs in a Plutus ' +
    '<code>Value</code> in O(1) time. ' +
    '(2D visualization: Value Size vs Time - constant cost)'],
+  ['policies', 'Policies',
+   'Returns the currency symbols of a Plutus <code>Value</code>; linear in the number ' +
+   'of policies. (2D visualization: Policy Count vs Time)'],
   ['listtoarray', 'ListToArray',
    'Converts a Plutus list to an array representation. ' +
    '(2D visualization: List Size vs Time)'],

diff --git a/plutus-core/changelog.d/20260819_154936_yuriy.lazaryev_policies_costing.md b/plutus-core/changelog.d/20260819_154936_yuriy.lazaryev_policies_costing.md
@@ -0,0 +1,3 @@
+### Added
+
+- Cost model for the `policies` builtin ([CIP-0168](https://cips.cardano.org/cip/CIP-0168)), with four new cost model parameters. Linear in the number of policies in the `Value`.
diff --git a/plutus-core/cost-model/budgeting-bench/Benchmarks/Values.hs b/plutus-core/cost-model/budgeting-bench/Benchmarks/Values.hs
@@ -25,6 +25,7 @@ import PlutusCore
       ( AssetCount
       , InsertCoin
       , LookupCoin
+      , Policies
       , ScaleValue
       , UnValueData
       , UnionValue
@@ -37,6 +38,7 @@ import PlutusCore.Builtin (BuiltinResult (BuiltinFailure, BuiltinSuccess, Builti
 import PlutusCore.Evaluation.Machine.ExMemoryUsage
   ( DataNodeCount (..)
   , ValueMaxDepth (..)
+  , ValueOuterSize (..)
   , ValueTotalSize (..)
   )
 import PlutusCore.Value
@@ -67,6 +69,7 @@ makeBenchmarks gen =
   , unionValueBenchmark gen
   , scaleValueBenchmark gen
   , assetCountBenchmark gen
+  , policiesBenchmark gen
   ]
 
 ----------------------------------------------------------------------------------------------------
@@ -390,6 +393,53 @@ assetCountBenchmark gen =
     []
     (generateTestValues gen)
 
+-- Policies ----------------------------------------------------------------------------------------
+
+{- Note [Benchmarking policies]
+`policies` is \(O(m)\) in the size of the outer map, which is exactly what
+`ValueOuterSize` (the measure the denotation uses) reports, so the fit applies to any
+shape of `Value`.
+
+The number of policies is sampled uniformly on a log scale, which puts a similar number
+of points in 1-10, 10-100, 100-1000 and so on. Sampling uniformly on the count itself
+would put almost every point above 1000, leaving the sizes that occur on chain
+unmeasured.
+
+The token count per policy is random under a total-size cap: the inner maps are never
+traversed, so it must not show in the measurements, and the fixed-size stacks (1000 and
+5000 policies at several token counts) would make a violation visible as vertical spread
+at a single x.
+-}
+policiesBenchmark :: StdGen -> Benchmark
+policiesBenchmark gen =
+  createOneTermBuiltinBenchWithWrapper_NF ValueOuterSize Policies [] (runBenchGen gen policiesArgs)
+  where
+    -- 40k pairs: safely above the largest `Value` a script can build within the
+    -- CPU budget (roughly 14k `insertCoin` applications).
+    maxTotalSize :: Int
+    maxTotalSize = Value.valueDataMaxSize
+
+    policiesArgs :: StatefulGen g m => g -> m [Value]
+    policiesArgs g = do
+      randoms <- replicateM 100 do
+        u <- uniformRM (0 :: Double, log (fromIntegral maxTotalSize)) g
+        let numPolicies = min maxTotalSize (max 1 (round (exp u)))
+        numTokens <- uniformRM (1, maxTotalSize `div` numPolicies) g
+        generate g numPolicies numTokens
+      stacks <-
+        sequence
+          [ generate g m k
+          | (m, ks) <- [(1000, [1, 2, 5, 10, 20, 40]), (5000, [1, 2, 4, 8])]
+          , k <- ks
+          ]
+      pure $ Value.empty : randoms <> stacks
+
+    generate :: StatefulGen g m => g -> Int -> Int -> m Value
+    generate g numPolicies numTokens = do
+      policyIds <- replicateM numPolicies (generateKey g)
+      tokenNames <- replicateM numTokens (generateKey g)
+      pure $ buildValue policyIds tokenNames (mkQuantity 1)
+
 ----------------------------------------------------------------------------------------------------
 -- Value Generators --------------------------------------------------------------------------------
 

diff --git a/plutus-core/cost-model/create-cost-model/BuiltinMemoryModels.hs b/plutus-core/cost-model/create-cost-model/BuiltinMemoryModels.hs
@@ -383,6 +383,10 @@ builtinMemoryModels =
       -- intercept keeps the cost nonzero for the empty index list.
       paramMultiIndexArray = Id $ ModelTwoArgumentsLinearInY $ OneVariableLinearFunction 4 3
     , paramAssetCount = Id $ ModelOneArgumentConstantCost 10
+    , -- `policies` returns the outer map's keys. The bytestrings are shared with the
+      -- `Value`, so only the list spine is new, at three words per cons cell (as for
+      -- `multiIndexArray`). The size measure is the number of policies (`ValueOuterSize`).
+      paramPolicies = Id $ ModelOneArgumentLinearInX $ OneVariableLinearFunction 4 3
     }
   where
     identityFunction = OneVariableLinearFunction 0 1
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		### Added

		- Cost model for the `policies` builtin ([CIP-0168](https://cips.cardano.org/cip/CIP-0168)), with four new cost model parameters. Linear in the number of policies in the `Value`.