diff --git a/.eslintignore b/.eslintignore
new file mode 100644
index 00000000..ea4d4ad1
--- /dev/null
+++ b/.eslintignore
@@ -0,0 +1,3 @@
+node_modules/
+packages/*/node_modules/
+packages/*/lib/
\ No newline at end of file
diff --git a/.eslintrc.json b/.eslintrc.json
index db3c608d..241986aa 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -10,11 +10,12 @@
     "no-unused-vars": "off",
     "eslint-comments/no-use": "off",
     "import/no-namespace": "off",
-    "@typescript-eslint/no-unused-vars": "error"
+    "@typescript-eslint/no-unused-vars": "error",
+    "@typescript-eslint/explicit-member-accessibility": ["error", {"accessibility": "no-public"}]
   },
   "env": {
     "node": true,
     "es6": true,
     "jest/globals": true
   }
-}
\ No newline at end of file
+}
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 00000000..ea4d4ad1
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,3 @@
+node_modules/
+packages/*/node_modules/
+packages/*/lib/
\ No newline at end of file
diff --git a/docs/package-specs.md b/docs/package-specs.md
index 21861fb0..b318251e 100644
--- a/docs/package-specs.md
+++ b/docs/package-specs.md
@@ -47,10 +47,16 @@ export interface InputOptions {
 export function getInput(name: string, options?: InputOptions): string | undefined
 
 /**
- * fail the action
+ * sets the status of the action to neutral
  * @param message 
  */
-export function setFailure(message: string): void
+export function setNeutral(message: string): void
+
+/**
+ * sets the status of the action to failed
+ * @param message 
+ */
+export function setFailed(message: string): void
 ```
 
 ### IO spec
diff --git a/package.json b/package.json
index e4cd4f30..da897d50 100644
--- a/package.json
+++ b/package.json
@@ -5,9 +5,9 @@
     "bootstrap": "lerna bootstrap",
     "build": "lerna run tsc",
     "check-all": "concurrently \"npm:format-check\" \"npm:lint\" \"npm:test\" \"npm:build -- -- --noEmit\"",
-    "format": "prettier --write packages/*/src/**/*.ts",
-    "format-check": "prettier --check packages/*/src/**/*.ts",
-    "lint": "eslint packages/*/src/**/*.ts",
+    "format": "prettier --write packages/**/*.ts",
+    "format-check": "prettier --check packages/**/*.ts",
+    "lint": "eslint packages/**/*.ts",
     "new-package": "scripts/create-package",
     "test": "jest"
   },
diff --git a/packages/core/README.md b/packages/core/README.md
new file mode 100644
index 00000000..d5bf5bab
--- /dev/null
+++ b/packages/core/README.md
@@ -0,0 +1,7 @@
+# `@actions/core`
+
+> Core functions for setting results, logging, registering secrets and exporting variables across actions
+
+## Usage
+
+See [src/core.ts](src/core.ts).
diff --git a/packages/core/__tests__/lib.test.ts b/packages/core/__tests__/lib.test.ts
new file mode 100644
index 00000000..a21b51e1
--- /dev/null
+++ b/packages/core/__tests__/lib.test.ts
@@ -0,0 +1,159 @@
+import * as os from 'os'
+import * as core from '../src/core'
+
+const testEnvVars = {
+  'my var': '',
+  'special char var \r\n];': '',
+  'my var2': '',
+  'my secret': '',
+  'special char secret \r\n];': '',
+  'my secret2': '',
+
+  // Set inputs
+  INPUT_MY_INPUT: 'val',
+  INPUT_MISSING: '',
+  'INPUT_SPECIAL_CHARS_\'\t"\\': '\'\t"\\ repsonse '
+}
+
+describe('@actions/core', () => {
+  beforeEach(() => {
+    for (const key in testEnvVars)
+      process.env[key] = testEnvVars[key as keyof typeof testEnvVars]
+
+    process.stdout.write = jest.fn()
+  })
+
+  afterEach(() => {
+    for (const key in testEnvVars) Reflect.deleteProperty(testEnvVars, key)
+  })
+
+  it('exportVariable produces the correct command and sets the env', () => {
+    core.exportVariable('my var', 'var val')
+    assertWriteCalls([`##[set-env name=my var;]var val${os.EOL}`])
+  })
+
+  it('exportVariable escapes variable names', () => {
+    core.exportVariable('special char var \r\n];', 'special val')
+    expect(process.env['special char var \r\n];']).toBe('special val')
+    assertWriteCalls([
+      `##[set-env name=special char var %0D%0A%5D%3B;]special val${os.EOL}`
+    ])
+  })
+
+  it('exportVariable escapes variable values', () => {
+    core.exportVariable('my var2', 'var val\r\n')
+    expect(process.env['my var2']).toBe('var val\r\n')
+    assertWriteCalls([`##[set-env name=my var2;]var val%0D%0A${os.EOL}`])
+  })
+
+  it('exportSecret produces the correct commands and sets the env', () => {
+    core.exportSecret('my secret', 'secret val')
+    expect(process.env['my secret']).toBe('secret val')
+    assertWriteCalls([
+      `##[set-env name=my secret;]secret val${os.EOL}`,
+      `##[set-secret]secret val${os.EOL}`
+    ])
+  })
+
+  it('exportSecret escapes secret names', () => {
+    core.exportSecret('special char secret \r\n];', 'special secret val')
+    expect(process.env['special char secret \r\n];']).toBe('special secret val')
+    assertWriteCalls([
+      `##[set-env name=special char secret %0D%0A%5D%3B;]special secret val${
+        os.EOL
+      }`,
+      `##[set-secret]special secret val${os.EOL}`
+    ])
+  })
+
+  it('exportSecret escapes secret values', () => {
+    core.exportSecret('my secret2', 'secret val\r\n')
+    expect(process.env['my secret2']).toBe('secret val\r\n')
+    assertWriteCalls([
+      `##[set-env name=my secret2;]secret val%0D%0A${os.EOL}`,
+      `##[set-secret]secret val%0D%0A${os.EOL}`
+    ])
+  })
+
+  it('getInput gets non-required input', () => {
+    expect(core.getInput('my input')).toBe('val')
+  })
+
+  it('getInput gets required input', () => {
+    expect(core.getInput('my input', {required: true})).toBe('val')
+  })
+
+  it('getInput throws on missing required input', () => {
+    expect(() => core.getInput('missing', {required: true})).toThrow(
+      'Input required and not supplied: missing'
+    )
+  })
+
+  it('getInput doesnt throw on missing non-required input', () => {
+    expect(core.getInput('missing', {required: false})).toBe('')
+  })
+
+  it('getInput is case insensitive', () => {
+    expect(core.getInput('My InPuT')).toBe('val')
+  })
+
+  it('getInput handles special characters', () => {
+    expect(core.getInput('special chars_\'\t"\\')).toBe('\'\t"\\ repsonse')
+  })
+
+  it('setNeutral sets the correct exit code', () => {
+    core.setFailed('Failure message')
+    expect(process.exitCode).toBe(1)
+  })
+
+  it('setFailure sets the correct exit code and failure message', () => {
+    core.setFailed('Failure message')
+    expect(process.exitCode).toBe(1)
+    assertWriteCalls([`##[error]Failure message${os.EOL}`])
+  })
+
+  it('setFailure escapes the failure message', () => {
+    core.setFailed('Failure \r\n\nmessage\r')
+    expect(process.exitCode).toBe(1)
+    assertWriteCalls([`##[error]Failure %0D%0A%0Amessage%0D${os.EOL}`])
+  })
+
+  it('error sets the correct error message', () => {
+    core.error('Error message')
+    assertWriteCalls([`##[error]Error message${os.EOL}`])
+  })
+
+  it('error escapes the error message', () => {
+    core.error('Error message\r\n\n')
+    assertWriteCalls([`##[error]Error message%0D%0A%0A${os.EOL}`])
+  })
+
+  it('warning sets the correct message', () => {
+    core.warning('Warning')
+    assertWriteCalls([`##[warning]Warning${os.EOL}`])
+  })
+
+  it('warning escapes the message', () => {
+    core.warning('\r\nwarning\n')
+    assertWriteCalls([`##[warning]%0D%0Awarning%0A${os.EOL}`])
+  })
+
+  it('debug sets the correct message', () => {
+    core.debug('Debug')
+    assertWriteCalls([`##[debug]Debug${os.EOL}`])
+  })
+
+  it('debug escapes the message', () => {
+    core.debug('\r\ndebug\n')
+    assertWriteCalls([`##[debug]%0D%0Adebug%0A${os.EOL}`])
+  })
+})
+
+// Assert that process.stdout.write calls called only with the given arguments.
+function assertWriteCalls(calls: string[]) {
+  expect(process.stdout.write).toHaveBeenCalledTimes(calls.length)
+
+  for (let i = 0; i < calls.length; i++) {
+    expect(process.stdout.write).toHaveBeenNthCalledWith(i + 1, calls[i])
+  }
+}
diff --git a/packages/core/package-lock.json b/packages/core/package-lock.json
new file mode 100644
index 00000000..fef7996a
--- /dev/null
+++ b/packages/core/package-lock.json
@@ -0,0 +1,14 @@
+{
+  "name": "@actions/core",
+  "version": "0.1.0",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "@types/node": {
+      "version": "12.0.2",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-12.0.2.tgz",
+      "integrity": "sha512-5tabW/i+9mhrfEOUcLDu2xBPsHJ+X5Orqy9FKpale3SjDA17j5AEpYq5vfy3oAeAHGcvANRCO3NV3d2D6q3NiA==",
+      "dev": true
+    }
+  }
+}
diff --git a/packages/core/package.json b/packages/core/package.json
new file mode 100644
index 00000000..df9eb6b7
--- /dev/null
+++ b/packages/core/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "@actions/core",
+  "version": "0.1.0",
+  "description": "Actions core lib",
+  "keywords": [
+    "core",
+    "actions"
+  ],
+  "author": "Bryan MacFarlane <bryanmac@microsoft.com>",
+  "homepage": "https://github.com/actions/toolkit/tree/master/packages/core",
+  "license": "MIT",
+  "main": "lib/core.js",
+  "directories": {
+    "lib": "lib",
+    "test": "__tests__"
+  },
+  "files": [
+    "lib"
+  ],
+  "publishConfig": {
+    "access": "public"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/actions/toolkit.git"
+  },
+  "scripts": {
+    "test": "echo \"Error: run tests from root\" && exit 1",
+    "tsc": "tsc"
+  },
+  "bugs": {
+    "url": "https://github.com/actions/toolkit/issues"
+  },
+  "devDependencies": {
+    "@types/node": "^12.0.2"
+  },
+  "dependencies": {
+    "@actions/exit": "^0.0.0"
+  }
+}
diff --git a/packages/core/src/command.ts b/packages/core/src/command.ts
new file mode 100644
index 00000000..b277bfb2
--- /dev/null
+++ b/packages/core/src/command.ts
@@ -0,0 +1,87 @@
+import * as os from 'os'
+
+// For internal use, subject to change.
+
+/**
+ * Commands
+ *
+ * Command Format:
+ *   ##[name key=value;key=value]message
+ *
+ * Examples:
+ *   ##[warning]This is the user warning message
+ *   ##[set-secret name=mypassword]definatelyNotAPassword!
+ */
+export function issueCommand(
+  command: string,
+  properties: any,
+  message: string
+) {
+  const cmd = new Command(command, properties, message)
+  process.stdout.write(cmd.toString() + os.EOL)
+}
+
+export function issue(name: string, message: string) {
+  issueCommand(name, {}, message)
+}
+
+const CMD_PREFIX = '##['
+
+class Command {
+  constructor(
+    command: string,
+    properties: {[key: string]: string},
+    message: string
+  ) {
+    if (!command) {
+      command = 'missing.command'
+    }
+
+    this.command = command
+    this.properties = properties
+    this.message = message
+  }
+
+  command: string
+  message: string
+  properties: {[key: string]: string}
+
+  toString() {
+    let cmdStr = CMD_PREFIX + this.command
+
+    if (this.properties && Object.keys(this.properties).length > 0) {
+      cmdStr += ' '
+      for (const key in this.properties) {
+        if (this.properties.hasOwnProperty(key)) {
+          const val = this.properties[key]
+          if (val) {
+            // safely append the val - avoid blowing up when attempting to
+            // call .replace() if message is not a string for some reason
+            cmdStr += `${key}=${escape(`${val || ''}`)};`
+          }
+        }
+      }
+    }
+
+    cmdStr += ']'
+
+    // safely append the message - avoid blowing up when attempting to
+    // call .replace() if message is not a string for some reason
+    const message: string = `${this.message || ''}`
+    cmdStr += escapeData(message)
+
+    return cmdStr
+  }
+}
+
+function escapeData(s: string): string {
+  return s.replace(/\r/g, '%0D').replace(/\n/g, '%0A')
+}
+
+function escape(s: string): string {
+  return s
+    .replace(/\r/g, '%0D')
+    .replace(/\n/g, '%0A')
+    .replace(/]/g, '%5D')
+    .replace(/;/g, '%3B')
+}
diff --git a/packages/core/src/core.ts b/packages/core/src/core.ts
new file mode 100644
index 00000000..408b9ad1
--- /dev/null
+++ b/packages/core/src/core.ts
@@ -0,0 +1,100 @@
+import {ExitCode} from '@actions/exit'
+import {issue, issueCommand} from './command'
+
+/**
+ * Interface for getInput options
+ */
+export interface InputOptions {
+  /** Optional. Whether the input is required. If required and not present, will throw. Defaults to false */
+  required?: boolean
+}
+
+//-----------------------------------------------------------------------
+// Variables
+//-----------------------------------------------------------------------
+
+/**
+ * sets env variable for this action and future actions in the job
+ * @param name the name of the variable to set
+ * @param val the value of the variable
+ */
+export function exportVariable(name: string, val: string) {
+  process.env[name] = val
+  issueCommand('set-env', {name}, val)
+}
+
+/**
+ * exports the variable and registers a secret which will get masked from logs
+ * @param name the name of the variable to set
+ * @param val value of the secret
+ */
+export function exportSecret(name: string, val: string) {
+  exportVariable(name, val)
+  issueCommand('set-secret', {}, val)
+}
+
+/**
+ * Gets the value of an input.  The value is also trimmed.
+ *
+ * @param     name     name of the input to get
+ * @param     options  optional. See InputOptions.
+ * @returns   string
+ */
+export function getInput(name: string, options?: InputOptions): string {
+  const val: string =
+    process.env[`INPUT_${name.replace(' ', '_').toUpperCase()}`] || ''
+  if (options && options.required && !val) {
+    throw new Error(`Input required and not supplied: ${name}`)
+  }
+
+  return val.trim()
+}
+
+//-----------------------------------------------------------------------
+// Results
+//-----------------------------------------------------------------------
+
+/**
+ * Sets the action status to neutral
+ */
+export function setNeutral() {
+  process.exitCode = ExitCode.Neutral
+}
+
+/**
+ * Sets the action status to failed.
+ * When the action exits it will be with an exit code of 1
+ * @param message add error issue message
+ */
+export function setFailed(message: string) {
+  process.exitCode = ExitCode.Failure
+  error(message)
+}
+
+//-----------------------------------------------------------------------
+// Logging Commands
+//-----------------------------------------------------------------------
+
+/**
+ * Writes debug message to user log
+ * @param message debug message
+ */
+export function debug(message: string) {
+  issueCommand('debug', {}, message)
+}
+
+/**
+ * Adds an error issue
+ * @param message error issue message
+ */
+export function error(message: string) {
+  issue('error', message)
+}
+
+/**
+ * Adds an warning issue
+ * @param message warning issue message
+ */
+export function warning(message: string) {
+  issue('warning', message)
+}
diff --git a/packages/core/tsconfig.json b/packages/core/tsconfig.json
new file mode 100644
index 00000000..a8b812a6
--- /dev/null
+++ b/packages/core/tsconfig.json
@@ -0,0 +1,11 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "baseUrl": "./",
+    "outDir": "./lib",
+    "rootDir": "./src"
+  },
+  "include": [
+    "./src"
+  ]
+}
\ No newline at end of file
diff --git a/packages/exit/README.md b/packages/exit/README.md
index c54d04da..cbbe0eef 100644
--- a/packages/exit/README.md
+++ b/packages/exit/README.md
@@ -4,8 +4,4 @@
 
 ## Usage
 
-```
-const exit = require('@actions/exit');
-
-// TODO: DEMONSTRATE API
-```
+See [src/exit.ts](src/exit.ts).
\ No newline at end of file
diff --git a/packages/toolkit/README.md b/packages/toolkit/README.md
index 1e2abbd7..fa5277da 100644
--- a/packages/toolkit/README.md
+++ b/packages/toolkit/README.md
@@ -4,8 +4,4 @@
 
 ## Usage
 
-```
-const github = require('@actions/toolkit');
-
-// TODO: DEMONSTRATE API
-```
+See [src/toolkit.ts](src/toolkit.ts).
\ No newline at end of file