diff --git a/.prettierrc b/.prettierrc
index 8b8417d..8304ba3 100644
--- a/.prettierrc
+++ b/.prettierrc
@@ -1,5 +1,5 @@
 {
   "semi": false,
-  "printWidth": 120,
+  "printWidth": 100,
   "singleQuote": false
 }
diff --git a/src/command.ts b/src/command.ts
index e8313d0..346614b 100644
--- a/src/command.ts
+++ b/src/command.ts
@@ -1,7 +1,8 @@
 import { z } from "zod"
 import { ValidationError } from "./error"
-import MassargOption, { MassargFlag, MassargNumber, OptionConfig, TypedOptionConfig } from "./option"
-import { generateCommandsHelpTable, generateOptionsHelpTable, isZodError } from "./utils"
+import Massarg from "./massarg"
+import MassargOption, { TypedOptionConfig } from "./option"
+import { generateCommandsHelpTable, generateOptionsHelpTable, isZodError, setOrPush } from "./utils"
 
 export const CommandConfig = <RunArgs extends z.ZodType>(args: RunArgs) =>
   z.object({
@@ -10,8 +11,10 @@ export const CommandConfig = <RunArgs extends z.ZodType>(args: RunArgs) =>
     aliases: z.string().array().optional(),
     run: z
       .function()
-      .args(args)
-      .returns(z.union([z.promise(z.void()), z.void()])) as z.ZodType<(args: z.infer<RunArgs>) => Promise<void> | void>,
+      .args(args, z.any())
+      .returns(z.union([z.promise(z.void()), z.void()])) as z.ZodType<
+      (args: z.infer<RunArgs>, instance: MassargCommand<z.infer<RunArgs>>) => Promise<void> | void
+    >,
   })
 
 export type CommandConfig<T = unknown> = z.infer<ReturnType<typeof CommandConfig<z.ZodType<T>>>>
@@ -24,7 +27,10 @@ export default class MassargCommand<Args extends ArgsObject = ArgsObject> {
   name: string
   description: string
   aliases: string[]
-  private _run?: (options: Args) => Promise<void> | void
+  private _run?: <P extends ArgsObject = Args>(
+    options: Args,
+    instance: Massarg<P>,
+  ) => Promise<void> | void
   options: MassargOption[] = []
   commands: MassargCommand<any>[] = []
   args: Partial<Args> = {}
@@ -34,12 +40,14 @@ export default class MassargCommand<Args extends ArgsObject = ArgsObject> {
     this.name = options.name
     this.description = options.description
     this.aliases = options.aliases ?? []
-    this._run = options.run
+    this._run = options.run as typeof this._run
   }
 
   command<A extends ArgsObject = Args>(config: CommandConfig<A>): MassargCommand<Args>
   command<A extends ArgsObject = Args>(config: MassargCommand<A>): MassargCommand<Args>
-  command<A extends ArgsObject = Args>(config: CommandConfig<A> | MassargCommand<A>): MassargCommand<Args> {
+  command<A extends ArgsObject = Args>(
+    config: CommandConfig<A> | MassargCommand<A>,
+  ): MassargCommand<Args> {
     try {
       const command = config instanceof MassargCommand ? config : new MassargCommand(config)
       this.commands.push(command)
@@ -47,7 +55,7 @@ export default class MassargCommand<Args extends ArgsObject = ArgsObject> {
     } catch (e) {
       if (isZodError(e)) {
         throw new ValidationError({
-          path: [config.name, ...e.issues[0].path.map((p) => p.toString())],
+          path: [this.name, config.name, ...e.issues[0].path.map((p) => p.toString())],
           code: e.issues[0].code,
           message: e.issues[0].message,
         })
@@ -60,13 +68,14 @@ export default class MassargCommand<Args extends ArgsObject = ArgsObject> {
   option<T = string>(config: TypedOptionConfig<T>): MassargCommand<Args>
   option<T = string>(config: TypedOptionConfig<T> | MassargOption<T>): MassargCommand<Args> {
     try {
-      const option = config instanceof MassargOption ? config : MassargOption.fromTypedConfig(config)
+      const option =
+        config instanceof MassargOption ? config : MassargOption.fromTypedConfig(config)
       this.options.push(option as MassargOption)
       return this
     } catch (e) {
       if (isZodError(e)) {
         throw new ValidationError({
-          path: [config.name, ...e.issues[0].path.map((p) => p.toString())],
+          path: [this.name, config.name, ...e.issues[0].path.map((p) => p.toString())],
           code: e.issues[0].code,
           message: e.issues[0].message,
         })
@@ -75,65 +84,84 @@ export default class MassargCommand<Args extends ArgsObject = ArgsObject> {
     }
   }
 
-  main(run: (options: Args) => Promise<void> | void): MassargCommand<Args> {
-    this._run = run
+  main<A extends ArgsObject = Args>(
+    run: (options: Args, instance: MassargCommand<A>) => Promise<void> | void,
+  ): MassargCommand<Args> {
+    this._run = run as typeof this._run
     return this
   }
 
-  parse(argv: string[], args?: Partial<Args>): Promise<void> | void {
-    console.log("parse:", this.name)
-    console.log(argv)
+  parse(argv: string[], args?: Partial<Args>, parent?: MassargCommand<Args>): Promise<void> | void {
     this.args ??= {}
     this.args = { ...this.args, ...args }
     let _argv = [...argv]
     while (_argv.length) {
       const arg = _argv.shift()!
-      console.log("parsing:", arg, _argv)
       const found = this.options.some((o) => o._isOption(arg))
       if (found) {
-        console.log("option:", arg, _argv)
         _argv = this.parseOption(arg, _argv)
         continue
       }
 
       const command = this.commands.find((c) => c.name === arg || c.aliases.includes(arg))
       if (command) {
-        console.log("command:", arg, _argv)
-        return command.parse(_argv, this.args)
+        return command.parse(_argv, this.args, parent ?? this)
       }
       // TODO pass all un-handled args to an "args" option
-      console.log("Nothing to do", arg, _argv)
     }
     if (this._run) {
-      console.log("run:", this.args)
-      this._run({ ...args, ...this.args } as Args)
+      this._run({ ...args, ...this.args } as Args, parent ?? this)
     }
   }
 
-  private parseOption(arg: string, argv: string[]): string[] {
+  private parseOption(arg: string, argv: string[]) {
     const option = this.options.find((o) => o._match(arg))
-
     if (!option) {
-      // TODO create custom error object
-      throw new Error(`Unknown option ${arg}`)
+      throw new ValidationError({
+        path: [arg],
+        code: "unknown_option",
+        message: "Unknown option",
+      })
     }
-    const res = option.valueFromArgv([arg, ...argv])
-    console.log("option class name", option.constructor.name)
-    if (option.isArray) {
-      this.args[res.key as keyof Args] ??= [] as Args[keyof Args]
-      const _a = this.args[res.key as keyof Args] as unknown[]
-      _a.push(res.value) as Args[keyof Args]
-    } else {
-      this.args[res.key as keyof Args] = res.value as Args[keyof Args]
-    }
-    console.log("option response:", { value: res.value, argv: res.argv })
+    const res = option._parseDetails([arg, ...argv])
+    this.args[res.key as keyof Args] = setOrPush<Args[keyof Args]>(
+      res.value,
+      this.args[res.key as keyof Args],
+      option.isArray,
+    )
     return res.argv
   }
 
   getArgs(argv: string[]): Args {
-    console.log("getArgs:", this.name)
-    console.log(argv)
-    return {} as Args
+    let args: Args = {} as Args
+    let _argv = [...argv]
+    while (_argv.length) {
+      const arg = _argv.shift()!
+      const found = this.options.some((o) => o._isOption(arg))
+      if (found) {
+        const option = this.options.find((o) => o._match(arg))
+        if (!option) {
+          throw new ValidationError({
+            path: [arg],
+            code: "unknown_option",
+            message: "Unknown option",
+          })
+        }
+        const res = option._parseDetails(argv)
+        args[res.key as keyof Args] = setOrPush<Args[keyof Args]>(
+          res.value,
+          args[res.key as keyof Args],
+          option.isArray,
+        )
+        continue
+      }
+
+      const command = this.commands.find((c) => c.name === arg || c.aliases.includes(arg))
+      if (command) {
+        break
+      }
+    }
+    return args
   }
 
   helpString(): string {
@@ -151,6 +179,10 @@ export default class MassargCommand<Args extends ArgsObject = ArgsObject> {
       .filter((s) => typeof s === "string")
       .join("\n")
   }
+
+  printHelp(): void {
+    console.log(this.helpString())
+  }
 }
 
 export { MassargCommand }
diff --git a/src/error.ts b/src/error.ts
index 3b24e0e..4ef089e 100644
--- a/src/error.ts
+++ b/src/error.ts
@@ -16,13 +16,28 @@ export class ParseError extends Error {
   path: string[]
   code: string
   message: string
+  received: unknown
 
-  constructor({ path, code, message }: { path: string[]; code: string; message: string }) {
-    const msg = `${path.join(".")}: ${message}`
+  constructor({
+    path,
+    code,
+    message,
+    received,
+  }: {
+    path: string[]
+    code: string
+    message: string
+    received?: unknown
+  }) {
+    let msg = `${path.join(".")}: ${message}`
+    if (received) {
+      msg += ` (received: ${received})`
+    }
     super(msg)
     this.path = path
     this.code = code
     this.message = msg
     this.name = "ParseError"
+    this.received = received
   }
 }
diff --git a/src/example.ts b/src/example.ts
index c40e59b..bcce0ca 100644
--- a/src/example.ts
+++ b/src/example.ts
@@ -7,10 +7,11 @@ const args = massarg<A>({
   name: "my-cli",
   description: "This is an example CLI",
 })
-  // .main((opts) => {
-  //   console.log("Main command - printing all opts")
-  //   console.log(opts)
-  // })
+  .main((opts, parser) => {
+    console.log("Main command - printing all opts")
+    console.log(opts, "\n")
+    parser.printHelp()
+  })
   .command(
     massarg<{ component: string }>({
       name: "add",
@@ -70,7 +71,7 @@ const args = massarg<A>({
   )
   .option({
     name: "bool",
-    description: "Example number option",
+    description: "Example boolean option",
     aliases: ["b"],
     type: "boolean",
   })
@@ -83,6 +84,6 @@ const args = massarg<A>({
 
 const opts = args.getArgs(process.argv.slice(2))
 
-console.log("Opts:", opts)
+console.log("Opts:", opts, "\n")
 
 args.parse(process.argv.slice(2))
diff --git a/src/massarg.ts b/src/massarg.ts
index 5893f5e..4ca7c05 100644
--- a/src/massarg.ts
+++ b/src/massarg.ts
@@ -19,7 +19,7 @@ export default class Massarg<Args extends ArgsObject = ArgsObject> extends Massa
 export { Massarg }
 
 export function massarg<Args extends ArgsObject = ArgsObject>(
-  options: MinimalCommandConfig<Args>,
+  options: MinimalCommandConfig<Args>
 ): MassargCommand<Args> {
   return new Massarg(options)
 }
diff --git a/src/option.ts b/src/option.ts
index 4708599..b41ec05 100644
--- a/src/option.ts
+++ b/src/option.ts
@@ -19,7 +19,9 @@ export const TypedOptionConfig = <T extends z.ZodType>(type: T) =>
       type: z.enum(["string", "number", "boolean"]).optional(),
     }),
   )
-export type TypedOptionConfig<T = unknown> = z.infer<ReturnType<typeof TypedOptionConfig<z.ZodType<T>>>>
+export type TypedOptionConfig<T = unknown> = z.infer<
+  ReturnType<typeof TypedOptionConfig<z.ZodType<T>>>
+>
 
 export const ArrayOptionConfig = <T extends z.ZodType>(type: T) =>
   TypedOptionConfig(z.array(type)).merge(
@@ -27,8 +29,11 @@ export const ArrayOptionConfig = <T extends z.ZodType>(type: T) =>
       defaultValue: z.array(type).optional(),
     }),
   )
-export type ArrayOptionConfig<T = unknown> = z.infer<ReturnType<typeof ArrayOptionConfig<z.ZodType<T>>>>
+export type ArrayOptionConfig<T = unknown> = z.infer<
+  ReturnType<typeof ArrayOptionConfig<z.ZodType<T>>>
+>
 
+// TODO turn to options
 const OPT_FULL_PREFIX = "--"
 const OPT_SHORT_PREFIX = "-"
 const NEGATE_FULL_PREFIX = "no-"
@@ -64,11 +69,13 @@ export default class MassargOption<T = unknown> {
     return new MassargOption(config as OptionConfig<T>)
   }
 
-  valueFromArgv(argv: string[]): ArgvValue<T> {
+  _parseDetails(argv: string[]): ArgvValue<T> {
     // TODO: support --option=value
     argv.shift()
+    let input = ""
     try {
-      const value = this.parse(argv.shift()!)
+      input = argv.shift()!
+      const value = this.parse(input)
       return { key: this.name, value, argv }
     } catch (e) {
       if (isZodError(e)) {
@@ -76,6 +83,7 @@ export default class MassargOption<T = unknown> {
           path: [this.name, ...e.issues[0].path.map((p) => p.toString())],
           code: e.issues[0].code,
           message: e.issues[0].message,
+          received: JSON.stringify(input),
         })
       }
       throw e
@@ -109,7 +117,11 @@ export default class MassargOption<T = unknown> {
   }
 
   _isOption(arg: string): boolean {
-    return arg.startsWith(OPT_FULL_PREFIX) || arg.startsWith(OPT_SHORT_PREFIX) || arg.startsWith(NEGATE_SHORT_PREFIX)
+    return (
+      arg.startsWith(OPT_FULL_PREFIX) ||
+      arg.startsWith(OPT_SHORT_PREFIX) ||
+      arg.startsWith(NEGATE_SHORT_PREFIX)
+    )
   }
 }
 
@@ -121,14 +133,15 @@ export class MassargNumber extends MassargOption<number> {
     })
   }
 
-  valueFromArgv(argv: string[]): ArgvValue<number> {
+  _parseDetails(argv: string[]): ArgvValue<number> {
     try {
-      const { argv: _argv, value } = super.valueFromArgv(argv)
+      const { argv: _argv, value } = super._parseDetails(argv)
       if (isNaN(value)) {
         throw new ParseError({
           path: [this.name],
           code: "invalid_type",
           message: "Expected a number",
+          received: JSON.stringify(argv[0]),
         })
       }
       return { key: this.name, value, argv: _argv }
@@ -138,6 +151,7 @@ export class MassargNumber extends MassargOption<number> {
           path: [this.name, ...e.issues[0].path.map((p) => p.toString())],
           code: e.issues[0].code,
           message: e.issues[0].message,
+          received: JSON.stringify(argv[0]),
         })
       }
       throw e
@@ -153,7 +167,7 @@ export class MassargFlag extends MassargOption<boolean> {
     })
   }
 
-  valueFromArgv(argv: string[]): ArgvValue<boolean> {
+  _parseDetails(argv: string[]): ArgvValue<boolean> {
     try {
       const isNegation = argv[0]?.startsWith("^")
       argv.shift()
diff --git a/src/utils.ts b/src/utils.ts
index db72a65..c0d36b8 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -50,7 +50,10 @@ export function generateHelpTable(
   return table.join("\n")
 }
 
-export function generateOptionsHelpTable(options: MassargOption<unknown>[], config?: GenerateTableOptions): string {
+export function generateOptionsHelpTable(
+  options: MassargOption<unknown>[],
+  config?: GenerateTableOptions,
+): string {
   return generateHelpTable(options, {
     namePrefix: "--",
     aliasPrefix: "-",
@@ -58,10 +61,24 @@ export function generateOptionsHelpTable(options: MassargOption<unknown>[], conf
   })
 }
 
-export function generateCommandsHelpTable(commands: MassargCommand[], config?: GenerateTableOptions): string {
+export function generateCommandsHelpTable(
+  commands: MassargCommand[],
+  config?: GenerateTableOptions,
+): string {
   return generateHelpTable(commands, {
     namePrefix: "",
     aliasPrefix: "",
     ...config,
   })
 }
+
+export function setOrPush<T>(
+  newValue: unknown,
+  currentValue: T[] | T | undefined,
+  isArray: boolean,
+): T {
+  if (isArray) {
+    return [...((currentValue as unknown[]) ?? []), newValue] as T
+  }
+  return newValue as T
+}