diff --git a/CHANGELOG.md b/CHANGELOG.md
index d36dcefae9..4fc88a0a02 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - **Breaking change** (TypeScript only) The `*.d.ts` files now contain TypeScript 3.8 features, `#private`, which is not usable in older versions
 - **Breaking change** - `api.derive.staking.*` has updated result types and detects support for lazy payouts queries
 - Rework type generation for `api.{query, tx}` to properly handle complex type inputs (Thanks to https://github.com/monitz87)
+- Rework metadata `--strict` mode to effectively decorate chain metadata (Thanks to https://github.com/monitz87)
 - Add `api.rpc.chain.subscribeAllHeads` (not just best) (Thanks to https://github.com/jak-pan)
 - Add `api.rpc.engine.*` for manual seal support
 - Add `api.injectMetadata(metadata)` to initialize API with a specific metadata version
diff --git a/packages/api/src/augment/consts.ts b/packages/api/src/augment/consts.ts
index fd3372bba0..3cea72851e 100644
--- a/packages/api/src/augment/consts.ts
+++ b/packages/api/src/augment/consts.ts
@@ -1,4 +1,4 @@
-// Auto-generated via `yarn polkadot-types-from-defs`, do not edit
+// Auto-generated via `yarn polkadot-types-from-chain`, do not edit
 /* eslint-disable @typescript-eslint/no-empty-interface */
 
 import { Codec } from '@polkadot/types/types';
@@ -12,7 +12,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
   export interface Constants {
     [index: string]: ModuleConstants;
     babe: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The number of **slots** that an epoch takes. We couple sessions to
        * epochs, i.e. we start a new session once the new epoch begins.
@@ -28,7 +28,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       expectedBlockTime: AugmentedConst<Moment>;
     };
     timestamp: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The minimum period between blocks. Beware that this is different to the *expected* period
        * that the block production apparatus provides. Your chosen consensus system will generally
@@ -38,14 +38,14 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       minimumPeriod: AugmentedConst<Moment>;
     };
     balances: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The minimum amount required to keep an account open.
        **/
       existentialDeposit: AugmentedConst<Balance>;
     };
     transactionPayment: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The fee to be paid for making a transaction; the base.
        **/
@@ -56,7 +56,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       transactionByteFee: AugmentedConst<BalanceOf>;
     };
     staking: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * Number of sessions per era.
        **/
@@ -67,7 +67,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       bondingDuration: AugmentedConst<EraIndex>;
     };
     session: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * Used as first key for `NextKeys` and `KeyOwner` to put all the data into the same branch
        * of the trie.
@@ -75,7 +75,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       dedupKeyPrefix: AugmentedConst<Bytes>;
     };
     democracy: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The minimum period of locking and the period between a proposal being approved and enacted.
        * It should generally be a little more than the unstake period to ensure that
@@ -109,7 +109,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       preimageByteDeposit: AugmentedConst<BalanceOf>;
     };
     elections: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       candidacyBond: AugmentedConst<BalanceOf>;
       votingBond: AugmentedConst<BalanceOf>;
       desiredMembers: AugmentedConst<u32>;
@@ -117,7 +117,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       termDuration: AugmentedConst<BlockNumber>;
     };
     finalityTracker: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The number of recent samples to keep from this chain. Default is 101.
        **/
@@ -128,7 +128,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       reportLatency: AugmentedConst<BlockNumber>;
     };
     treasury: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * Fraction of a proposal's value that should be bonded in order to place the proposal.
        * An accepted proposal gets these back. A rejected proposal does not.
@@ -164,7 +164,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       tipReportDepositPerByte: AugmentedConst<BalanceOf>;
     };
     contracts: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * Number of block delay an extrinsic claim surcharge has.
        * When claim surcharge is called by an extrinsic the rent is checked
@@ -237,7 +237,7 @@ declare module '@polkadot/metadata/Decorated/consts/types' {
       blockGasLimit: AugmentedConst<Gas>;
     };
     society: {
-      [index: string]: Codec;
+      [index: string]: AugmentedConst<object & Codec>;
       /**
        * The minimum amount of a deposit required for a bid to be made.
        **/
diff --git a/packages/api/src/augment/query.ts b/packages/api/src/augment/query.ts
index 89909cd72d..e7bd0ebfcd 100644
--- a/packages/api/src/augment/query.ts
+++ b/packages/api/src/augment/query.ts
@@ -1,4 +1,4 @@
-// Auto-generated via `yarn polkadot-types-from-defs`, do not edit
+// Auto-generated via `yarn polkadot-types-from-chain`, do not edit
 /* eslint-disable @typescript-eslint/no-empty-interface */
 
 import { AnyNumber, ITuple } from '@polkadot/types/types';
diff --git a/packages/api/src/augment/rpc.ts b/packages/api/src/augment/rpc.ts
index 03f8c6474c..caf9effdf8 100644
--- a/packages/api/src/augment/rpc.ts
+++ b/packages/api/src/augment/rpc.ts
@@ -1,4 +1,4 @@
-// Auto-generated via `yarn polkadot-types-from-defs`, do not edit
+// Auto-generated via `yarn polkadot-types-from-chain`, do not edit
 /* eslint-disable @typescript-eslint/no-empty-interface */
 
 import { AnyNumber, Codec, IExtrinsic } from '@polkadot/types/types';
diff --git a/packages/api/src/augment/tx.ts b/packages/api/src/augment/tx.ts
index cace3aa548..6815f3866b 100644
--- a/packages/api/src/augment/tx.ts
+++ b/packages/api/src/augment/tx.ts
@@ -1,4 +1,4 @@
-// Auto-generated via `yarn polkadot-types-from-defs`, do not edit
+// Auto-generated via `yarn polkadot-types-from-chain`, do not edit
 /* eslint-disable @typescript-eslint/no-empty-interface */
 
 import { AnyNumber, ITuple } from '@polkadot/types/types';
@@ -17,8 +17,7 @@ import { SocietyJudgement } from '@polkadot/types/interfaces/society';
 import { EraIndex, RewardDestination, ValidatorPrefs } from '@polkadot/types/interfaces/staking';
 import { Key } from '@polkadot/types/interfaces/system';
 import { Timepoint } from '@polkadot/types/interfaces/utility';
-import { SubmittableExtrinsic } from '@polkadot/api/submittable/types';
-import { ApiTypes } from '@polkadot/api/types';
+import { ApiTypes, SubmittableExtrinsic } from '@polkadot/api/types';
 
 declare module '@polkadot/api/types/submittable' {
   export interface AugmentedSubmittables<ApiType> {
diff --git a/packages/typegen/src/generate/consts.ts b/packages/typegen/src/generate/consts.ts
index e5cbb2edc6..458684a0f6 100644
--- a/packages/typegen/src/generate/consts.ts
+++ b/packages/typegen/src/generate/consts.ts
@@ -19,10 +19,12 @@ function generateModule (allDefs: object, { constants, name }: ModuleMetadataLat
     return [];
   }
 
-  setImports(allDefs, imports, ['Codec']);
+  if (!isStrict) {
+    setImports(allDefs, imports, ['Codec']);
+  }
 
   return [indent(4)(`${stringCamelCase(name.toString())}: {`)]
-    .concat(isStrict ? '' : indent(6)('[index: string]: Codec;'))
+    .concat(isStrict ? '' : indent(6)('[index: string]: AugmentedConst<object & Codec>;'))
     .concat(constants.map(({ documentation, name, type }): string => {
       setImports(allDefs, imports, [type.toString()]);
 
@@ -43,7 +45,7 @@ function generateForMeta (meta: Metadata, dest: string, extraTypes: Record<strin
     const body = meta.asLatest.modules.reduce((acc, mod): string[] => {
       return acc.concat(generateModule(allDefs, mod, imports, isStrict));
     }, [] as string[]);
-    const header = createImportCode(HEADER, imports, [
+    const header = createImportCode(HEADER('chain'), imports, [
       ...Object.keys(imports.localTypes).sort().map((moduleName): { file: string; types: string[] } => ({
         file: `${imports.moduleToPackage[moduleName]}/${moduleName}`,
         types: Object.keys(imports.localTypes[moduleName])
diff --git a/packages/typegen/src/generate/interfaceRegistry.ts b/packages/typegen/src/generate/interfaceRegistry.ts
index 3772a83a8d..468225a2dc 100644
--- a/packages/typegen/src/generate/interfaceRegistry.ts
+++ b/packages/typegen/src/generate/interfaceRegistry.ts
@@ -44,7 +44,7 @@ export function generateInterfaceTypes (importDefinitions: { [importPath: string
       ].join('\n');
     }, '');
 
-    const header = createImportCode(HEADER, imports, [
+    const header = createImportCode(HEADER('defs'), imports, [
       ...Object.keys(imports.localTypes).sort().map((moduleName): { file: string; types: string[] } => ({
         file: `${imports.moduleToPackage[moduleName]}/${moduleName}`,
         types: Object.keys(imports.localTypes[moduleName])
diff --git a/packages/typegen/src/generate/query.ts b/packages/typegen/src/generate/query.ts
index 24bca66b45..333addf21f 100644
--- a/packages/typegen/src/generate/query.ts
+++ b/packages/typegen/src/generate/query.ts
@@ -46,7 +46,7 @@ function entrySignature (allDefs: object, registry: Registry, storageEntry: Stor
       formatType(allDefs, addModifier(storageEntry, storageEntry.type.asMap.value.toString()), imports)
     ];
   } else if (storageEntry.type.isDoubleMap) {
-    // Find similartypes of `key1` and `key2` types
+    // Find similar types of `key1` and `key2` types
     const similarTypes1 = getSimilarTypes(allDefs, registry, storageEntry.type.asDoubleMap.key1.toString(), imports);
     const similarTypes2 = getSimilarTypes(allDefs, registry, storageEntry.type.asDoubleMap.key2.toString(), imports);
 
@@ -102,7 +102,7 @@ function generateForMeta (registry: Registry, meta: Metadata, dest: string, extr
     const body = meta.asLatest.modules.reduce((acc: string[], mod): string[] => {
       return acc.concat(generateModule(allDefs, registry, mod, imports, isStrict));
     }, []);
-    const header = createImportCode(HEADER, imports, [
+    const header = createImportCode(HEADER('chain'), imports, [
       ...Object.keys(imports.localTypes).sort().map((moduleName): { file: string; types: string[] } => ({
         file: `${imports.moduleToPackage[moduleName]}/${moduleName}`,
         types: Object.keys(imports.localTypes[moduleName])
diff --git a/packages/typegen/src/generate/rpc.ts b/packages/typegen/src/generate/rpc.ts
index e3a01e7b7b..b3b671acd2 100644
--- a/packages/typegen/src/generate/rpc.ts
+++ b/packages/typegen/src/generate/rpc.ts
@@ -48,7 +48,7 @@ export default function generateRpcTypes (dest = 'packages/api/src/augment/rpc.t
       );
     }, []).join('\n');
 
-    const header = createImportCode(HEADER, imports, [
+    const header = createImportCode(HEADER('chain'), imports, [
       ...Object.keys(imports.localTypes).sort().map((moduleName): { file: string; types: string[] } => ({
         file: `@polkadot/types/interfaces/${moduleName}`,
         types: Object.keys(imports.localTypes[moduleName])
diff --git a/packages/typegen/src/generate/tsDef.ts b/packages/typegen/src/generate/tsDef.ts
index d9567474ff..b3e551af57 100644
--- a/packages/typegen/src/generate/tsDef.ts
+++ b/packages/typegen/src/generate/tsDef.ts
@@ -184,7 +184,7 @@ function generateTsDefFor (importDefinitions: { [importPath: string]: object },
   const interfaces = generateInterfaces(definitions, { types }, imports);
   const sortedDefs = interfaces.sort((a, b): number => a[0].localeCompare(b[0])).map(([, definition]): string => definition).join('\n\n');
 
-  const header = createImportCode(HEADER, imports, [
+  const header = createImportCode(HEADER('defs'), imports, [
     ...Object.keys(imports.localTypes).sort().map((moduleName): { file: string; types: string[] } => ({
       file: `${imports.moduleToPackage[moduleName]}/${moduleName}`,
       types: Object.keys(imports.localTypes[moduleName])
@@ -192,7 +192,7 @@ function generateTsDefFor (importDefinitions: { [importPath: string]: object },
   ]);
 
   fs.writeFileSync(path.join(outputDir, defName, 'types.ts'), header.concat(sortedDefs).concat(FOOTER), { flag: 'w' });
-  fs.writeFileSync(path.join(outputDir, defName, 'index.ts'), HEADER.concat('export * from \'./types\';').concat(FOOTER), { flag: 'w' });
+  fs.writeFileSync(path.join(outputDir, defName, 'index.ts'), HEADER('defs').concat('export * from \'./types\';').concat(FOOTER), { flag: 'w' });
 }
 
 /** @internal */
@@ -206,7 +206,7 @@ export function generateTsDef (importDefinitions: { [importPath: string]: object
       generateTsDefFor(importDefinitions, defName, obj, outputDir);
     });
 
-    return HEADER
+    return HEADER('defs')
       .concat(
         Object
           .keys(definitions)
@@ -216,7 +216,7 @@ export function generateTsDef (importDefinitions: { [importPath: string]: object
       .concat(FOOTER);
   });
 
-  fs.writeFileSync(path.join(outputDir, 'index.ts'), HEADER.concat('export * from \'./types\';').concat(FOOTER), { flag: 'w' });
+  fs.writeFileSync(path.join(outputDir, 'index.ts'), HEADER('defs').concat('export * from \'./types\';').concat(FOOTER), { flag: 'w' });
 }
 
 /** @internal */
diff --git a/packages/typegen/src/generate/tx.ts b/packages/typegen/src/generate/tx.ts
index 07a11b5256..50375b1423 100644
--- a/packages/typegen/src/generate/tx.ts
+++ b/packages/typegen/src/generate/tx.ts
@@ -70,18 +70,14 @@ function generateForMeta (registry: Registry, meta: Metadata, dest: string, extr
     const body = meta.asLatest.modules.reduce((acc, mod): string[] => {
       return acc.concat(generateModule(registry, allDefs, mod, imports, isStrict));
     }, [] as string[]);
-    const header = createImportCode(HEADER, imports, [
+    const header = createImportCode(HEADER('chain'), imports, [
       ...Object.keys(imports.localTypes).sort().map((moduleName): { file: string; types: string[] } => ({
         file: `${imports.moduleToPackage[moduleName]}/${moduleName}`,
         types: Object.keys(imports.localTypes[moduleName])
       })),
-      {
-        file: '@polkadot/api/submittable/types',
-        types: ['SubmittableExtrinsic']
-      },
       {
         file: '@polkadot/api/types',
-        types: ['ApiTypes']
+        types: ['ApiTypes', 'SubmittableExtrinsic']
       }
     ]);
     const interfaceStart = [
diff --git a/packages/typegen/src/util/formatting.ts b/packages/typegen/src/util/formatting.ts
index 4024aa7820..8a37a718d9 100644
--- a/packages/typegen/src/util/formatting.ts
+++ b/packages/typegen/src/util/formatting.ts
@@ -9,7 +9,7 @@ import { paramsNotation } from '@polkadot/types/codec/utils';
 
 import { setImports, TypeImports } from './imports';
 
-export const HEADER = '// Auto-generated via `yarn polkadot-types-from-defs`, do not edit\n/* eslint-disable @typescript-eslint/no-empty-interface */\n\n';
+export const HEADER = (type: 'chain' | 'defs'): string => `// Auto-generated via \`yarn polkadot-types-from-${type}\`, do not edit\n/* eslint-disable @typescript-eslint/no-empty-interface */\n\n`;
 export const FOOTER = '\n';
 
 const TYPES_NON_PRIMITIVE = ['Metadata'];