diff --git a/.github/workflows/publish-model-catalog.yml b/.github/workflows/publish-model-catalog.yml
new file mode 100644
index 00000000..03641352
--- /dev/null
+++ b/.github/workflows/publish-model-catalog.yml
@@ -0,0 +1,112 @@
+name: Publish Model Catalog
+
+on:
+  workflow_run:
+    workflows:
+      - CI
+    types:
+      - completed
+  pull_request:
+    paths:
+      - '.github/workflows/publish-model-catalog.yml'
+      - '.gitignore'
+      - 'package.json'
+      - 'packages/ai/**'
+      - 'scripts/publish-model-catalog.mjs'
+  schedule:
+    - cron: '17 */4 * * *'
+  workflow_dispatch:
+    inputs:
+      source_ref:
+        description: 'Commit, branch, or tag to generate from'
+        required: false
+        default: 'main'
+        type: string
+      publish:
+        description: 'Upload the generated catalog to production R2'
+        required: true
+        default: false
+        type: boolean
+
+permissions:
+  contents: read
+
+jobs:
+  generate:
+    if: ${{ github.event_name != 'workflow_run' || (github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.head_branch == 'main') }}
+    runs-on: ubuntu-latest
+    env:
+      SOURCE_REF: ${{ github.event.workflow_run.head_sha || github.event.pull_request.head.sha || inputs.source_ref || github.sha }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          ref: ${{ env.SOURCE_REF }}
+          persist-credentials: false
+
+      - name: Setup Node.js
+        uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af # v4.1.0
+        with:
+          node-version: '22'
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci --ignore-scripts
+
+      - name: Generate model catalog JSON
+        run: npm run generate:model-catalog
+
+      - name: Validate model catalog JSON
+        run: npm run check:model-catalog
+
+      - name: Upload model catalog JSON
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: model-catalog-json
+          path: .artifacts/model-catalog
+          if-no-files-found: error
+          retention-days: 14
+
+  publish:
+    if: ${{ github.event_name == 'schedule' || github.event_name == 'workflow_run' || (github.event_name == 'workflow_dispatch' && inputs.publish) }}
+    needs: generate
+    runs-on: ubuntu-latest
+    environment: pi-model-upload
+    concurrency:
+      group: publish-model-catalog-r2
+      cancel-in-progress: true
+    env:
+      SOURCE_REF: ${{ github.event.workflow_run.head_sha || inputs.source_ref || github.sha }}
+      AWS_ACCESS_KEY_ID: ${{ secrets.PI_ARTIFACTS_R2_ACCESS_KEY_ID }}
+      AWS_SECRET_ACCESS_KEY: ${{ secrets.PI_ARTIFACTS_R2_SECRET_ACCESS_KEY }}
+      AWS_DEFAULT_REGION: auto
+      AWS_EC2_METADATA_DISABLED: 'true'
+      R2_ENDPOINT: https://67c0d357268b0fca6e0b465bb9d01b84.r2.cloudflarestorage.com
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          ref: ${{ env.SOURCE_REF }}
+          persist-credentials: false
+
+      - name: Setup Node.js
+        uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af # v4.1.0
+        with:
+          node-version: '22'
+
+      - name: Download model catalog JSON
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
+        with:
+          name: model-catalog-json
+          path: .artifacts/model-catalog
+
+      - name: Verify AWS CLI
+        run: aws --version
+
+      - name: Publish model catalog to R2
+        run: |
+          node scripts/publish-model-catalog.mjs \
+            --input .artifacts/model-catalog \
+            --bucket pi-artifacts \
+            --endpoint "$R2_ENDPOINT" \
+            --source-commit "$(git rev-parse HEAD)"
diff --git a/.gitignore b/.gitignore
index 12a09a8f..49dc29c7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 node_modules/
 dist/
+.artifacts/
 *.log
 .DS_Store
 *.tsbuildinfo
diff --git a/package.json b/package.json
index 4ec90289..83462d28 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,8 @@
 		"check:shrinkwrap": "node scripts/generate-coding-agent-shrinkwrap.mjs --check",
 		"check:install-lock:coding-agent": "node scripts/generate-coding-agent-install-lock.mjs --check",
 		"check:ts-imports": "node scripts/check-ts-relative-imports.mjs",
+		"generate:model-catalog": "npm --prefix packages/ai run generate-model-catalog",
+		"check:model-catalog": "node scripts/publish-model-catalog.mjs --input .artifacts/model-catalog --dry-run",
 		"profile:tui": "node scripts/profile-coding-agent-node.mjs --mode tui",
 		"profile:rpc": "node scripts/profile-coding-agent-node.mjs --mode rpc",
 		"test": "npm run test --workspaces --if-present",
diff --git a/packages/ai/package.json b/packages/ai/package.json
index d0edb56b..e2ecd28c 100644
--- a/packages/ai/package.json
+++ b/packages/ai/package.json
@@ -46,6 +46,7 @@
 	"scripts": {
 		"clean": "shx rm -rf dist",
 		"generate-models": "node scripts/generate-models.ts",
+		"generate-model-catalog": "node scripts/generate-models.ts --strict --json-only --json-output ../../.artifacts/model-catalog",
 		"generate-image-models": "node scripts/generate-image-models.ts",
 		"build": "npm run generate-models && npm run generate-image-models && tsgo -p tsconfig.build.json",
 		"test": "vitest --run",
diff --git a/packages/ai/scripts/generate-models.ts b/packages/ai/scripts/generate-models.ts
index 6f194818..d740182b 100644
--- a/packages/ai/scripts/generate-models.ts
+++ b/packages/ai/scripts/generate-models.ts
@@ -1,7 +1,7 @@
 #!/usr/bin/env node
 
-import { readdirSync, rmSync, writeFileSync } from "fs";
-import { join, dirname } from "path";
+import { mkdirSync, readdirSync, rmSync, writeFileSync } from "fs";
+import { dirname, join, resolve } from "path";
 import { fileURLToPath } from "url";
 import {
 	CLOUDFLARE_AI_GATEWAY_ANTHROPIC_BASE_URL,
@@ -22,6 +22,40 @@ const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
 const packageRoot = join(__dirname, "..");
 
+function readGeneratorOptions(args: string[]): {
+	strict: boolean;
+	jsonOnly: boolean;
+	jsonOutputDir: string | undefined;
+} {
+	let strict = false;
+	let jsonOnly = false;
+	let jsonOutputDir: string | undefined;
+
+	for (let index = 0; index < args.length; index++) {
+		const arg = args[index];
+		if (arg === "--strict") {
+			strict = true;
+			continue;
+		}
+		if (arg === "--json-only") {
+			jsonOnly = true;
+			continue;
+		}
+		if (arg === "--json-output") {
+			const value = args[++index];
+			if (!value) throw new Error("--json-output requires a directory");
+			jsonOutputDir = resolve(value);
+			continue;
+		}
+		throw new Error(`Unknown argument: ${arg}`);
+	}
+
+	if (jsonOnly && !jsonOutputDir) throw new Error("--json-only requires --json-output");
+	return { strict, jsonOnly, jsonOutputDir };
+}
+
+const generatorOptions = readGeneratorOptions(process.argv.slice(2));
+
 interface ModelsDevModel {
 	id: string;
 	name: string;
@@ -688,6 +722,7 @@ async function fetchNvidiaNimModelIds(): Promise<Map<string, string>> {
 	try {
 		console.log("Fetching models from NVIDIA NIM API...");
 		const response = await fetch(`${NVIDIA_BASE_URL}/models`);
+		if (!response.ok) throw new Error(`NVIDIA NIM API returned ${response.status}`);
 		const data = (await response.json()) as { data?: NvidiaNimModelListItem[] };
 		const modelIds = new Map<string, string>();
 
@@ -700,6 +735,7 @@ async function fetchNvidiaNimModelIds(): Promise<Map<string, string>> {
 		return modelIds;
 	} catch (error) {
 		console.error("Failed to fetch NVIDIA NIM models:", error);
+		if (generatorOptions.strict) throw error;
 		return new Map();
 	}
 }
@@ -708,6 +744,7 @@ async function fetchOpenRouterModels(): Promise<Model<any>[]> {
 	try {
 		console.log("Fetching models from OpenRouter API...");
 		const response = await fetch("https://openrouter.ai/api/v1/models");
+		if (!response.ok) throw new Error(`OpenRouter API returned ${response.status}`);
 		const data = await response.json();
 
 		const models: Model<any>[] = [];
@@ -760,6 +797,7 @@ async function fetchOpenRouterModels(): Promise<Model<any>[]> {
 		return models;
 	} catch (error) {
 		console.error("Failed to fetch OpenRouter models:", error);
+		if (generatorOptions.strict) throw error;
 		return [];
 	}
 }
@@ -768,6 +806,7 @@ async function fetchAiGatewayModels(): Promise<Model<any>[]> {
 	try {
 		console.log("Fetching models from Vercel AI Gateway API...");
 		const response = await fetch(`${AI_GATEWAY_MODELS_URL}/models`);
+		if (!response.ok) throw new Error(`Vercel AI Gateway API returned ${response.status}`);
 		const data = await response.json();
 		const models: Model<any>[] = [];
 
@@ -818,6 +857,7 @@ async function fetchAiGatewayModels(): Promise<Model<any>[]> {
 		return models;
 	} catch (error) {
 		console.error("Failed to fetch Vercel AI Gateway models:", error);
+		if (generatorOptions.strict) throw error;
 		return [];
 	}
 }
@@ -826,6 +866,7 @@ async function loadModelsDevData(): Promise<Model<any>[]> {
 	try {
 		console.log("Fetching models from models.dev API...");
 		const response = await fetch("https://models.dev/api.json");
+		if (!response.ok) throw new Error(`models.dev API returned ${response.status}`);
 		const data = await response.json();
 
 		const models: Model<any>[] = [];
@@ -1703,6 +1744,7 @@ async function loadModelsDevData(): Promise<Model<any>[]> {
 		return models;
 	} catch (error) {
 		console.error("Failed to load models.dev data:", error);
+		if (generatorOptions.strict) throw error;
 		return [];
 	}
 }
@@ -2236,85 +2278,110 @@ async function generateModels() {
 		}
 	}
 
-	// Generate TypeScript files: one catalog per provider plus an aggregator
-	const generatedHeader = `// This file is auto-generated by scripts/generate-models.ts
+	const sortedProviderIds = Object.keys(providers).sort();
+
+	if (!generatorOptions.jsonOnly) {
+		// Generate TypeScript files: one catalog per provider plus an aggregator
+		const generatedHeader = `// This file is auto-generated by scripts/generate-models.ts
 // Do not edit manually - run 'npm run generate-models' to update
 
 `;
-	const catalogConstName = (providerId: string) => `${providerId.toUpperCase().replace(/[^A-Z0-9]+/g, "_")}_MODELS`;
+		const catalogConstName = (providerId: string) =>
+			`${providerId.toUpperCase().replace(/[^A-Z0-9]+/g, "_")}_MODELS`;
 
-	function emitModel(model: Model<any>, indent: string): string {
-		let output = `${indent}"${model.id}": {\n`;
-		output += `${indent}\tid: "${model.id}",\n`;
-		output += `${indent}\tname: "${model.name}",\n`;
-		output += `${indent}\tapi: "${model.api}",\n`;
-		output += `${indent}\tprovider: "${model.provider}",\n`;
-		if (model.baseUrl !== undefined) {
-			output += `${indent}\tbaseUrl: "${model.baseUrl}",\n`;
+		function emitModel(model: Model<any>, indent: string): string {
+			let output = `${indent}"${model.id}": {\n`;
+			output += `${indent}\tid: "${model.id}",\n`;
+			output += `${indent}\tname: "${model.name}",\n`;
+			output += `${indent}\tapi: "${model.api}",\n`;
+			output += `${indent}\tprovider: "${model.provider}",\n`;
+			if (model.baseUrl !== undefined) {
+				output += `${indent}\tbaseUrl: "${model.baseUrl}",\n`;
+			}
+			if (model.headers) {
+				output += `${indent}\theaders: ${JSON.stringify(model.headers)},\n`;
+			}
+			if (model.compat) {
+				output += `${indent}\tcompat: ${JSON.stringify(model.compat)},\n`;
+			}
+			output += `${indent}\treasoning: ${model.reasoning},\n`;
+			if (model.thinkingLevelMap) {
+				output += `${indent}\tthinkingLevelMap: ${JSON.stringify(model.thinkingLevelMap)},\n`;
+			}
+			output += `${indent}\tinput: [${model.input.map(i => `"${i}"`).join(", ")}],\n`;
+			output += `${indent}\tcost: {\n`;
+			output += `${indent}\t\tinput: ${model.cost.input},\n`;
+			output += `${indent}\t\toutput: ${model.cost.output},\n`;
+			output += `${indent}\t\tcacheRead: ${model.cost.cacheRead},\n`;
+			output += `${indent}\t\tcacheWrite: ${model.cost.cacheWrite},\n`;
+			if (model.cost.tiers) {
+				output += `${indent}\t\ttiers: ${JSON.stringify(model.cost.tiers)},\n`;
+			}
+			output += `${indent}\t},\n`;
+			output += `${indent}\tcontextWindow: ${model.contextWindow},\n`;
+			output += `${indent}\tmaxTokens: ${model.maxTokens},\n`;
+			output += `${indent}} satisfies Model<"${model.api}">,\n`;
+			return output;
 		}
-		if (model.headers) {
-			output += `${indent}\theaders: ${JSON.stringify(model.headers)},\n`;
-		}
-		if (model.compat) {
-			output += `${indent}\tcompat: ${JSON.stringify(model.compat)},\n`;
-		}
-		output += `${indent}\treasoning: ${model.reasoning},\n`;
-		if (model.thinkingLevelMap) {
-			output += `${indent}\tthinkingLevelMap: ${JSON.stringify(model.thinkingLevelMap)},\n`;
-		}
-		output += `${indent}\tinput: [${model.input.map(i => `"${i}"`).join(", ")}],\n`;
-		output += `${indent}\tcost: {\n`;
-		output += `${indent}\t\tinput: ${model.cost.input},\n`;
-		output += `${indent}\t\toutput: ${model.cost.output},\n`;
-		output += `${indent}\t\tcacheRead: ${model.cost.cacheRead},\n`;
-		output += `${indent}\t\tcacheWrite: ${model.cost.cacheWrite},\n`;
-		if (model.cost.tiers) {
-			output += `${indent}\t\ttiers: ${JSON.stringify(model.cost.tiers)},\n`;
-		}
-		output += `${indent}\t},\n`;
-		output += `${indent}\tcontextWindow: ${model.contextWindow},\n`;
-		output += `${indent}\tmaxTokens: ${model.maxTokens},\n`;
-		output += `${indent}} satisfies Model<"${model.api}">,\n`;
-		return output;
-	}
 
-	const sortedProviderIds = Object.keys(providers).sort();
-	const providersDir = join(packageRoot, "src/providers");
+		const providersDir = join(packageRoot, "src/providers");
 
-	// Remove stale per-provider catalogs
-	for (const entry of readdirSync(providersDir)) {
-		if (entry.endsWith(".models.ts")) {
-			rmSync(join(providersDir, entry));
+		// Remove stale per-provider catalogs
+		for (const entry of readdirSync(providersDir)) {
+			if (entry.endsWith(".models.ts")) {
+				rmSync(join(providersDir, entry));
+			}
 		}
-	}
 
-	// Per-provider catalogs (sorted for deterministic output)
-	for (const providerId of sortedProviderIds) {
-		const models = providers[providerId];
+		// Per-provider catalogs (sorted for deterministic output)
+		for (const providerId of sortedProviderIds) {
+			const models = providers[providerId];
+			let output = generatedHeader;
+			output += `import type { Model } from "../types.ts";\n\n`;
+			output += `export const ${catalogConstName(providerId)} = {\n`;
+			const sortedModelIds = Object.keys(models).sort();
+			for (const modelId of sortedModelIds) {
+				output += emitModel(models[modelId], "\t");
+			}
+			output += `} as const;\n`;
+			writeFileSync(join(providersDir, `${providerId}.models.ts`), output);
+		}
+		console.log(`Generated ${sortedProviderIds.length} catalogs under src/providers/`);
+
+		// Aggregator
 		let output = generatedHeader;
-		output += `import type { Model } from "../types.ts";\n\n`;
-		output += `export const ${catalogConstName(providerId)} = {\n`;
-		const sortedModelIds = Object.keys(models).sort();
-		for (const modelId of sortedModelIds) {
-			output += emitModel(models[modelId], "\t");
+		for (const providerId of sortedProviderIds) {
+			output += `import { ${catalogConstName(providerId)} } from "./providers/${providerId}.models.ts";\n`;
+		}
+		output += `\nexport const MODELS = {\n`;
+		for (const providerId of sortedProviderIds) {
+			output += `\t${JSON.stringify(providerId)}: ${catalogConstName(providerId)},\n`;
 		}
 		output += `} as const;\n`;
-		writeFileSync(join(providersDir, `${providerId}.models.ts`), output);
+		writeFileSync(join(packageRoot, "src/models.generated.ts"), output);
+		console.log("Generated src/models.generated.ts");
 	}
-	console.log(`Generated ${sortedProviderIds.length} catalogs under src/providers/`);
 
-	// Aggregator
-	let output = generatedHeader;
-	for (const providerId of sortedProviderIds) {
-		output += `import { ${catalogConstName(providerId)} } from "./providers/${providerId}.models.ts";\n`;
+	if (generatorOptions.jsonOutputDir) {
+		const jsonProviders: Record<string, Record<string, Model<any>>> = {};
+		for (const providerId of sortedProviderIds) {
+			jsonProviders[providerId] = {};
+			for (const modelId of Object.keys(providers[providerId]).sort()) {
+				jsonProviders[providerId][modelId] = providers[providerId][modelId];
+			}
+		}
+
+		const providerOutputDir = join(generatorOptions.jsonOutputDir, "providers");
+		rmSync(generatorOptions.jsonOutputDir, { recursive: true, force: true });
+		mkdirSync(providerOutputDir, { recursive: true });
+		const writeJson = (path: string, value: unknown) => writeFileSync(path, `${JSON.stringify(value)}\n`);
+		writeJson(join(generatorOptions.jsonOutputDir, "models.json"), jsonProviders);
+		writeJson(join(generatorOptions.jsonOutputDir, "providers.json"), sortedProviderIds);
+		for (const providerId of sortedProviderIds) {
+			writeJson(join(providerOutputDir, `${providerId}.json`), jsonProviders[providerId]);
+		}
+		console.log(`Generated JSON model catalog under ${generatorOptions.jsonOutputDir}`);
 	}
-	output += `\nexport const MODELS = {\n`;
-	for (const providerId of sortedProviderIds) {
-		output += `\t${JSON.stringify(providerId)}: ${catalogConstName(providerId)},\n`;
-	}
-	output += `} as const;\n`;
-	writeFileSync(join(packageRoot, "src/models.generated.ts"), output);
-	console.log("Generated src/models.generated.ts");
 
 	// Print statistics
 	const totalModels = allModels.length;
@@ -2330,4 +2397,7 @@ async function generateModels() {
 }
 
 // Run the generator
-generateModels().catch(console.error);
+generateModels().catch((error) => {
+	console.error(error);
+	process.exitCode = 1;
+});
diff --git a/scripts/publish-model-catalog.mjs b/scripts/publish-model-catalog.mjs
new file mode 100644
index 00000000..a8a30d43
--- /dev/null
+++ b/scripts/publish-model-catalog.mjs
@@ -0,0 +1,295 @@
+#!/usr/bin/env node
+
+import { createHash } from "node:crypto";
+import {
+	mkdtempSync,
+	readFileSync,
+	readdirSync,
+	rmSync,
+	writeFileSync,
+} from "node:fs";
+import { tmpdir } from "node:os";
+import { join, resolve } from "node:path";
+import { spawnSync } from "node:child_process";
+import { isDeepStrictEqual } from "node:util";
+
+const CATALOG_SCHEMA_VERSION = 1;
+const CATALOG_PREFIX = `models/v${CATALOG_SCHEMA_VERSION}`;
+const CATALOG_INDEX_KEY = `${CATALOG_PREFIX}/index.json`;
+// Bump this only when generated model metadata requires behavior unavailable in older pi clients.
+const MINIMUM_PI_VERSION = "0.80.7";
+const JSON_CONTENT_TYPE = "application/json; charset=utf-8";
+const IMMUTABLE_CACHE_CONTROL = "public, max-age=31536000, immutable";
+const INDEX_CACHE_CONTROL = "no-store";
+const REQUIRED_PROVIDERS = ["anthropic", "openai", "openrouter"];
+const MINIMUM_MODEL_COUNT = 500;
+
+function parseArgs(args) {
+	const options = {
+		input: undefined,
+		bucket: undefined,
+		endpoint: undefined,
+		sourceCommit: undefined,
+		dryRun: false,
+	};
+
+	for (let index = 0; index < args.length; index++) {
+		const arg = args[index];
+		if (arg === "--dry-run") {
+			options.dryRun = true;
+			continue;
+		}
+		if (arg === "--input" || arg === "--bucket" || arg === "--endpoint" || arg === "--source-commit") {
+			const value = args[++index];
+			if (!value) throw new Error(`${arg} requires a value`);
+			options[
+				{
+					"--input": "input",
+					"--bucket": "bucket",
+					"--endpoint": "endpoint",
+					"--source-commit": "sourceCommit",
+				}[arg]
+			] = value;
+			continue;
+		}
+		throw new Error(`Unknown argument: ${arg}`);
+	}
+
+	if (!options.input) throw new Error("--input is required");
+	if (!options.dryRun && !options.bucket) throw new Error("--bucket is required when publishing");
+	if (!options.dryRun && !options.endpoint) throw new Error("--endpoint is required when publishing");
+	return options;
+}
+
+function readJson(path) {
+	return JSON.parse(readFileSync(path, "utf8"));
+}
+
+function isRecord(value) {
+	return typeof value === "object" && value !== null && !Array.isArray(value);
+}
+
+function validateBundle(inputDir) {
+	const modelsPath = join(inputDir, "models.json");
+	const providerIndexPath = join(inputDir, "providers.json");
+	const providersDir = join(inputDir, "providers");
+	const modelsBytes = readFileSync(modelsPath);
+	const models = JSON.parse(modelsBytes.toString("utf8"));
+	const providerIds = readJson(providerIndexPath);
+
+	if (!isRecord(models)) throw new Error("models.json must contain an object");
+	if (!Array.isArray(providerIds) || !providerIds.every((value) => typeof value === "string")) {
+		throw new Error("providers.json must contain an array of provider IDs");
+	}
+
+	const expectedProviderIds = Object.keys(models).sort();
+	if (!isDeepStrictEqual(providerIds, expectedProviderIds)) {
+		throw new Error("providers.json does not match the sorted providers in models.json");
+	}
+	for (const providerId of REQUIRED_PROVIDERS) {
+		if (!Object.hasOwn(models, providerId)) throw new Error(`Required provider is missing: ${providerId}`);
+	}
+
+	let modelCount = 0;
+	for (const providerId of providerIds) {
+		const providerModels = models[providerId];
+		if (!isRecord(providerModels)) throw new Error(`Provider catalog must be an object: ${providerId}`);
+		const providerFile = readJson(join(providersDir, `${providerId}.json`));
+		if (!isDeepStrictEqual(providerFile, providerModels)) {
+			throw new Error(`Provider shard does not match models.json: ${providerId}`);
+		}
+		for (const [modelId, model] of Object.entries(providerModels)) {
+			if (!isRecord(model) || model.id !== modelId || model.provider !== providerId) {
+				throw new Error(`Invalid model entry: ${providerId}/${modelId}`);
+			}
+			modelCount++;
+		}
+	}
+
+	const shardFiles = readdirSync(providersDir).filter((name) => name.endsWith(".json")).sort();
+	const expectedShardFiles = providerIds.map((providerId) => `${providerId}.json`).sort();
+	if (!isDeepStrictEqual(shardFiles, expectedShardFiles)) {
+		throw new Error("Provider shard files do not match providers.json");
+	}
+	if (modelCount < MINIMUM_MODEL_COUNT) {
+		throw new Error(`Refusing to publish only ${modelCount} models; expected at least ${MINIMUM_MODEL_COUNT}`);
+	}
+
+	const digest = createHash("sha256").update(modelsBytes).digest("hex");
+	return {
+		modelsPath,
+		providerIndexPath,
+		providersDir,
+		providerIds,
+		providerCount: providerIds.length,
+		modelCount,
+		revision: `sha256-${digest}`,
+	};
+}
+
+function gitSourceCommit() {
+	const result = spawnSync("git", ["rev-parse", "HEAD"], { encoding: "utf8" });
+	if (result.status !== 0) throw new Error(`Unable to determine source commit: ${result.stderr.trim()}`);
+	return result.stdout.trim();
+}
+
+function aws(args, { allowNotFound = false } = {}) {
+	const result = spawnSync("aws", args, {
+		encoding: "utf8",
+		env: {
+			...process.env,
+			AWS_DEFAULT_REGION: process.env.AWS_DEFAULT_REGION || "auto",
+			AWS_EC2_METADATA_DISABLED: "true",
+		},
+	});
+	if (result.error) throw result.error;
+	if (result.status === 0) return true;
+	const message = `${result.stdout}\n${result.stderr}`.trim();
+	if (allowNotFound && /(?:404|NoSuchKey|Not Found)/i.test(message)) return false;
+	throw new Error(`aws ${args.slice(0, 2).join(" ")} failed:\n${message}`);
+}
+
+function downloadIndex(bucket, endpoint, outputPath) {
+	return aws(
+		[
+			"s3",
+			"cp",
+			`s3://${bucket}/${CATALOG_INDEX_KEY}`,
+			outputPath,
+			"--endpoint-url",
+			endpoint,
+			"--only-show-errors",
+		],
+		{ allowNotFound: true },
+	);
+}
+
+function uploadJson(bucket, endpoint, sourcePath, key, cacheControl) {
+	aws([
+		"s3",
+		"cp",
+		sourcePath,
+		`s3://${bucket}/${key}`,
+		"--endpoint-url",
+		endpoint,
+		"--content-type",
+		JSON_CONTENT_TYPE,
+		"--cache-control",
+		cacheControl,
+		"--only-show-errors",
+	]);
+}
+
+function validateIndex(index) {
+	if (!isRecord(index) || index.schemaVersion !== CATALOG_SCHEMA_VERSION) {
+		throw new Error(`Existing ${CATALOG_INDEX_KEY} has an unsupported schema`);
+	}
+	if (!Array.isArray(index.catalogs)) throw new Error(`Existing ${CATALOG_INDEX_KEY} has no catalogs array`);
+	for (const catalog of index.catalogs) {
+		if (
+			!isRecord(catalog) ||
+			typeof catalog.minimumPiVersion !== "string" ||
+			typeof catalog.revision !== "string"
+		) {
+			throw new Error(`Existing ${CATALOG_INDEX_KEY} contains an invalid catalog entry`);
+		}
+	}
+	return index;
+}
+
+function comparePiVersions(left, right) {
+	const leftParts = left.split(".").map(Number);
+	const rightParts = right.split(".").map(Number);
+	for (let index = 0; index < Math.max(leftParts.length, rightParts.length); index++) {
+		const difference = (leftParts[index] || 0) - (rightParts[index] || 0);
+		if (difference !== 0) return difference;
+	}
+	return left.localeCompare(right);
+}
+
+function buildIndex(existingIndex, publication) {
+	const entry = {
+		minimumPiVersion: MINIMUM_PI_VERSION,
+		revision: publication.revision,
+		sourceCommit: publication.sourceCommit,
+		publishedAt: new Date().toISOString(),
+		providerCount: publication.providerCount,
+		modelCount: publication.modelCount,
+	};
+	const catalogs = (existingIndex?.catalogs || [])
+		.filter((catalog) => catalog.minimumPiVersion !== MINIMUM_PI_VERSION)
+		.concat(entry)
+		.sort((left, right) => comparePiVersions(left.minimumPiVersion, right.minimumPiVersion));
+	return {
+		schemaVersion: CATALOG_SCHEMA_VERSION,
+		defaultRevision: publication.revision,
+		catalogs,
+	};
+}
+
+async function main() {
+	const options = parseArgs(process.argv.slice(2));
+	const inputDir = resolve(options.input);
+	const bundle = validateBundle(inputDir);
+	const publication = {
+		schemaVersion: CATALOG_SCHEMA_VERSION,
+		minimumPiVersion: MINIMUM_PI_VERSION,
+		revision: bundle.revision,
+		sourceCommit: options.sourceCommit || gitSourceCommit(),
+		providerCount: bundle.providerCount,
+		modelCount: bundle.modelCount,
+	};
+	writeFileSync(join(inputDir, "publication.json"), `${JSON.stringify(publication, null, 2)}\n`);
+
+	console.log(JSON.stringify(publication, null, 2));
+	if (options.dryRun) {
+		console.log(`Validated model catalog at ${inputDir}; no objects uploaded.`);
+		return;
+	}
+
+	const temporaryDir = mkdtempSync(join(tmpdir(), "pi-model-catalog-"));
+	try {
+		const currentIndexPath = join(temporaryDir, "index-current.json");
+		const hasCurrentIndex = downloadIndex(options.bucket, options.endpoint, currentIndexPath);
+		const currentIndex = hasCurrentIndex ? validateIndex(readJson(currentIndexPath)) : undefined;
+		const currentEntry = currentIndex?.catalogs.find(
+			(catalog) => catalog.minimumPiVersion === MINIMUM_PI_VERSION,
+		);
+		if (currentIndex?.defaultRevision === bundle.revision && currentEntry?.revision === bundle.revision) {
+			console.log(`Model catalog ${bundle.revision} is already current; no objects uploaded.`);
+			return;
+		}
+
+		const revisionPrefix = `${CATALOG_PREFIX}/revisions/${bundle.revision}`;
+		uploadJson(options.bucket, options.endpoint, bundle.modelsPath, `${revisionPrefix}/models.json`, IMMUTABLE_CACHE_CONTROL);
+		uploadJson(
+			options.bucket,
+			options.endpoint,
+			bundle.providerIndexPath,
+			`${revisionPrefix}/providers.json`,
+			IMMUTABLE_CACHE_CONTROL,
+		);
+		for (const providerId of bundle.providerIds) {
+			uploadJson(
+				options.bucket,
+				options.endpoint,
+				join(bundle.providersDir, `${providerId}.json`),
+				`${revisionPrefix}/providers/${providerId}.json`,
+				IMMUTABLE_CACHE_CONTROL,
+			);
+		}
+
+		const nextIndex = buildIndex(currentIndex, publication);
+		const nextIndexPath = join(temporaryDir, "index-next.json");
+		writeFileSync(nextIndexPath, `${JSON.stringify(nextIndex, null, 2)}\n`);
+		uploadJson(options.bucket, options.endpoint, nextIndexPath, CATALOG_INDEX_KEY, INDEX_CACHE_CONTROL);
+		console.log(`Published ${bundle.revision} to s3://${options.bucket}/${revisionPrefix}`);
+	} finally {
+		rmSync(temporaryDir, { recursive: true, force: true });
+	}
+}
+
+main().catch((error) => {
+	console.error(error instanceof Error ? error.message : error);
+	process.exitCode = 1;
+});