diff --git a/server/chat-commands/info.ts b/server/chat-commands/info.ts
index be814ff80cea..5af54311eb3a 100644
--- a/server/chat-commands/info.ts
+++ b/server/chat-commands/info.ts
@@ -585,7 +585,7 @@ export const commands: Chat.ChatCommands = {
 		const gen = parseInt(cmd.substr(-1));
 		if (gen) target += `, gen${gen}`;
 
-		const {dex, format, targets} = this.splitFormat(target, true);
+		const {dex, format, targets} = this.splitFormat(target, true, true);
 
 		let buffer = '';
 		target = targets.join(',');
@@ -2819,7 +2819,7 @@ export const commands: Chat.ChatCommands = {
 			allowEmpty: true, useIDs: false,
 		});
 		const format = Dex.formats.get(toID(args.format[0]));
-		if (!format.exists) {
+		if (format.effectType !== 'Format') {
 			return this.popupReply(`The format '${format}' does not exist.`);
 		}
 		delete args.format;
@@ -3170,8 +3170,8 @@ export const pages: Chat.PageTable = {
 		buf += `<hr />`;
 		const formatId = toID(query[0]);
 		const format = Dex.formats.get(formatId);
-		if (!formatId || !format.exists) {
-			if (formatId && !format.exists) {
+		if (!formatId || format.effectType !== 'Format') {
+			if (formatId) {
 				buf += `<div class="message-error">The format '${formatId}' does not exist.</div><br />`;
 			}
 			buf += `<form data-submitsend="/buildformat {format}">`;
diff --git a/server/chat-commands/room-settings.ts b/server/chat-commands/room-settings.ts
index 99ce0d45efa6..76e1ce7589a9 100644
--- a/server/chat-commands/room-settings.ts
+++ b/server/chat-commands/room-settings.ts
@@ -1615,7 +1615,7 @@ export const commands: Chat.ChatCommands = {
 
 		target = toID(target);
 		const format = Dex.formats.get(target);
-		if (format.exists) {
+		if (format.effectType === 'Format') {
 			target = format.name;
 		}
 		const {isMatch} = this.extractFormat(target);
diff --git a/server/chat-plugins/datasearch.ts b/server/chat-plugins/datasearch.ts
index bfe1bd1c0339..8babc9960d18 100644
--- a/server/chat-plugins/datasearch.ts
+++ b/server/chat-plugins/datasearch.ts
@@ -1149,7 +1149,7 @@ function runDexsearch(target: string, cmd: string, canAll: boolean, message: str
 				// LC handling, checks for LC Pokemon in higher tiers that need to be handled separately,
 				// as well as event-only Pokemon that are not eligible for LC despite being the first stage
 				let format = Dex.formats.get('gen' + mod.gen + 'lc');
-				if (!format.exists) format = Dex.formats.get('gen9lc');
+				if (format.effectType !== 'Format') format = Dex.formats.get('gen9lc');
 				if (
 					alts.tiers.LC &&
 					!dex[mon].prevo &&
@@ -2576,7 +2576,7 @@ function runLearn(target: string, cmd: string, canAll: boolean, formatid: string
 	while (targets.length) {
 		const targetid = toID(targets[0]);
 		if (targetid === 'pentagon') {
-			if (format.exists) {
+			if (format.effectType === 'Format') {
 				return {error: "'pentagon' can't be used with formats."};
 			}
 			minSourceGen = 6;
@@ -2584,7 +2584,7 @@ function runLearn(target: string, cmd: string, canAll: boolean, formatid: string
 			continue;
 		}
 		if (targetid.startsWith('minsourcegen')) {
-			if (format.exists) {
+			if (format.effectType === 'Format') {
 				return {error: "'min source gen' can't be used with formats."};
 			}
 			minSourceGen = parseInt(targetid.slice(12));
@@ -2600,14 +2600,15 @@ function runLearn(target: string, cmd: string, canAll: boolean, formatid: string
 		break;
 	}
 	let gen;
-	if (!format.exists) {
+	if (format.effectType !== 'Format') {
+		if (!(formatid in Dex.dexes)) {
+			// can happen if you hotpatch formats without hotpatching chat
+			return {error: `"${formatid}" is not a supported format.`};
+		}
 		const dex = Dex.mod(formatid).includeData();
-		// can happen if you hotpatch formats without hotpatching chat
-		if (!dex) return {error: `"${formatid}" is not a supported format.`};
-
 		gen = dex.gen;
 		formatName = `Gen ${gen}`;
-		format = new Dex.Format({mod: formatid});
+		format = new Dex.Format({mod: formatid, effectType: 'Format', exists: true});
 		const ruleTable = dex.formats.getRuleTable(format);
 		if (minSourceGen) {
 			formatName += ` (Min Source Gen = ${minSourceGen})`;
diff --git a/server/chat-plugins/randombattles/index.ts b/server/chat-plugins/randombattles/index.ts
index e7111018c87d..d9ca18a6adea 100644
--- a/server/chat-plugins/randombattles/index.ts
+++ b/server/chat-plugins/randombattles/index.ts
@@ -857,7 +857,7 @@ export const commands: Chat.ChatCommands = {
 
 		if (!target) return this.parse('/help generateteam');
 		const format = Dex.formats.get(target);
-		if (!format.exists) throw new Chat.ErrorMessage(`"${target}" is not a recognized format.`);
+		if (format.effectType !== 'Format') throw new Chat.ErrorMessage(`"${target}" is not a recognized format.`);
 		if (!format.team) throw new Chat.ErrorMessage(`"${format.name}" requires you to bring your own team.`);
 
 		const team = Teams.getGenerator(format).getTeam();
diff --git a/server/chat-plugins/sample-teams.ts b/server/chat-plugins/sample-teams.ts
index 334b498000d0..3ff4663f3307 100644
--- a/server/chat-plugins/sample-teams.ts
+++ b/server/chat-plugins/sample-teams.ts
@@ -107,7 +107,7 @@ export const SampleTeams = new class SampleTeams {
 
 	sanitizeFormat(formatid: string, checkExists = false) {
 		const format = Dex.formats.get(formatid);
-		if (checkExists && !format.exists) {
+		if (checkExists && format.effectType !== 'Format') {
 			throw new Chat.ErrorMessage(`Format "${formatid.trim()}" not found. Check spelling?`);
 		}
 		if (format.team) {
diff --git a/server/chat-plugins/suspect-tests.ts b/server/chat-plugins/suspect-tests.ts
index 762e693b08ee..c5458c0a18bd 100644
--- a/server/chat-plugins/suspect-tests.ts
+++ b/server/chat-plugins/suspect-tests.ts
@@ -67,7 +67,7 @@ export const commands: Chat.ChatCommands = {
 			}
 
 			const format = Dex.formats.get(tier);
-			if (!format.exists) throw new Chat.ErrorMessage(`"${tier}" is not a valid tier.`);
+			if (format.effectType !== 'Format') throw new Chat.ErrorMessage(`"${tier}" is not a valid tier.`);
 
 			const suspectString = suspect.trim();
 
diff --git a/server/chat-plugins/teams.ts b/server/chat-plugins/teams.ts
index 280d288e736d..3d47713ac5dc 100644
--- a/server/chat-plugins/teams.ts
+++ b/server/chat-plugins/teams.ts
@@ -124,7 +124,7 @@ export const TeamsHandler = new class {
 		}
 		const user = connection.user;
 		const format = Dex.formats.get(toID(formatName));
-		if (!format.exists || format.team) {
+		if (format.effectType !== 'Format' || format.team) {
 			connection.popup("Invalid format:\n\n" + formatName);
 			return null;
 		}
diff --git a/server/chat.ts b/server/chat.ts
index 8ea704c06fe2..95c76921cf6a 100644
--- a/server/chat.ts
+++ b/server/chat.ts
@@ -291,19 +291,19 @@ export abstract class MessageContext {
 	 * for the format/mod, or the default dex if none was found), and
 	 * `targets` (the rest of the array).
 	 */
-	splitFormat(target: string | string[], atLeastOneTarget?: boolean) {
+	splitFormat(target: string | string[], atLeastOneTarget?: boolean, allowRules?: boolean) {
 		const targets = typeof target === 'string' ? target.split(',') : target;
 		if (!targets[0].trim()) targets.pop();
 
 		if (targets.length > (atLeastOneTarget ? 1 : 0)) {
-			const {dex, format, isMatch} = this.extractFormat(targets[0].trim());
+			const {dex, format, isMatch} = this.extractFormat(targets[0].trim(), allowRules);
 			if (isMatch) {
 				targets.shift();
 				return {dex, format, targets};
 			}
 		}
 		if (targets.length > 1) {
-			const {dex, format, isMatch} = this.extractFormat(targets[targets.length - 1].trim());
+			const {dex, format, isMatch} = this.extractFormat(targets[targets.length - 1].trim(), allowRules);
 			if (isMatch) {
 				targets.pop();
 				return {dex, format, targets};
@@ -311,16 +311,16 @@ export abstract class MessageContext {
 		}
 
 		const room = (this as any as CommandContext).room;
-		const {dex, format} = this.extractFormat(room?.settings.defaultFormat || room?.battle?.format);
+		const {dex, format} = this.extractFormat(room?.settings.defaultFormat || room?.battle?.format, allowRules);
 		return {dex, format, targets};
 	}
-	extractFormat(formatOrMod?: string): {dex: ModdedDex, format: Format | null, isMatch: boolean} {
+	extractFormat(formatOrMod?: string, allowRules?: boolean): {dex: ModdedDex, format: Format | null, isMatch: boolean} {
 		if (!formatOrMod) {
 			return {dex: Dex.includeData(), format: null, isMatch: false};
 		}
 
 		const format = Dex.formats.get(formatOrMod);
-		if (format.exists) {
+		if (format.effectType === 'Format' || allowRules && format.effectType === 'Rule') {
 			return {dex: Dex.forFormat(format), format: format, isMatch: true};
 		}
 
diff --git a/sim/dex-formats.ts b/sim/dex-formats.ts
index a70619fa877b..89813628c97b 100644
--- a/sim/dex-formats.ts
+++ b/sim/dex-formats.ts
@@ -628,7 +628,7 @@ export class DexFormats {
 	validate(name: string) {
 		const [formatName, customRulesString] = name.split('@@@', 2);
 		const format = this.get(formatName);
-		if (!format.exists) throw new Error(`Unrecognized format "${formatName}"`);
+		if (format.effectType !== 'Format') throw new Error(`Unrecognized format "${formatName}"`);
 		if (!customRulesString) return format.id;
 		const ruleTable = this.getRuleTable(format);
 		const customRules = customRulesString.split(',').map(rule => {
diff --git a/tools/set-import/importer.ts b/tools/set-import/importer.ts
index 8947035abd04..b9619962d978 100644
--- a/tools/set-import/importer.ts
+++ b/tools/set-import/importer.ts
@@ -55,7 +55,7 @@ const VALIDATORS = new Map<ID, TeamValidator>();
 for (let gen = 1; gen <= 9; gen++) {
 	for (const tier of TIERS) {
 		const format = Dex.formats.get(`gen${gen}${tier}`);
-		if (format.exists) {
+		if (format.effectType === 'Format') {
 			FORMATS.set(format.id, {gen: gen as GenerationNum, format});
 			VALIDATORS.set(format.id, new TeamValidator(format));
 		}