diff --git a/src/config/args.ts b/src/config/args.ts
index 45a7c95..cbb79fc 100644
--- a/src/config/args.ts
+++ b/src/config/args.ts
@@ -1,5 +1,6 @@
 import { Options, showCompletionScript, usage } from 'yargs';
 
+import { RuleSelector } from '../rule';
 import { VERSION_INFO } from '../version';
 
 export const CONFIG_ARGS_NAME = 'config-name';
@@ -16,25 +17,40 @@ export interface Args {
   mode: string;
 }
 
+export interface ParsedArgs extends RuleSelector {
+  [CONFIG_ARGS_NAME]: string;
+  [CONFIG_ARGS_PATH]: string;
+  coerce: boolean;
+  count: boolean;
+  defaults: boolean;
+  dest: string;
+  mode: string;
+  rules: Array<string>;
+  source: string;
+}
+
+export interface ParseResults {
+  args: ParsedArgs;
+  mode: string;
+}
+
 /**
  * Wrap yargs to exit after completion.
  *
  * @TODO: fix it to use argv, not sure if yargs can do that
  */
-export function parseArgs(argv: Array<string>) {
+export function parseArgs(argv: Array<string>): ParseResults {
   let mode = 'check';
 
-  const args = usage(`Usage: salty-dog <mode> [options]`)
+  const parser = usage(`Usage: salty-dog <mode> [options]`)
     .command({
       command: ['check', '*'],
       describe: 'validate the source documents',
-      handler: (argv: any) => {
+      handler: (argi: any) => {
         mode = 'check';
       },
     })
     .command({
-      command: ['fix'],
-      describe: 'validate the source document and insert defaults',
       builder: (yargs: any) => {
         return yargs
           .option('coerce', {
@@ -46,21 +62,23 @@ export function parseArgs(argv: Array<string>) {
             type: 'boolean',
           });
       },
-      handler: (argv: any) => {
+      command: ['fix'],
+      describe: 'validate the source document and insert defaults',
+      handler: (argi: any) => {
         mode = 'fix';
       },
     })
     .command({
       command: ['list'],
       describe: 'list active rules',
-      handler: (argv: any) => {
+      handler: (argi: any) => {
         mode = 'list';
       },
     })
     .command({
       command: ['complete'],
       describe: 'generate tab completion script for bash or zsh',
-      handler: (argv: any) => {
+      handler: (argi: any) => {
         mode = 'complete';
       },
     })
@@ -112,8 +130,11 @@ export function parseArgs(argv: Array<string>) {
     })
     .help()
     .version(VERSION_INFO.app.version)
-    .alias('version', 'v')
-    .argv;
+    .alias('version', 'v');
+
+  // @TODO: this should not need a cast but argv's type only has the last option (include-tag)
+  // @tslint:disable-next-line:no-any
+  const args = parser.argv as any;
 
   if (mode === 'complete') {
     showCompletionScript();
diff --git a/src/config/index.ts b/src/config/index.ts
index 539ef5c..16a4023 100644
--- a/src/config/index.ts
+++ b/src/config/index.ts
@@ -1,14 +1,26 @@
+import { Stream } from 'bunyan';
 import { isNil, isString } from 'lodash';
+import { LogLevel } from 'noicejs';
 import { join } from 'path';
 
-import { CONFIG_ENV, CONFIG_SCHEMA } from './schema';
-import { includeSchema } from './type/Include';
 import { NotFoundError } from '../error/NotFoundError';
 import { YamlParser } from '../parser/YamlParser';
 import { readFileSync } from '../source';
+import { CONFIG_ENV, CONFIG_SCHEMA } from './schema';
+import { includeSchema } from './type/Include';
 
 includeSchema.schema = CONFIG_SCHEMA;
 
+export interface ConfigData {
+  data: {
+    logger: {
+      level: LogLevel;
+      name: string;
+      streams: Array<Stream>;
+    };
+  };
+}
+
 /**
  * With the given name, generate all potential config paths in their complete, absolute form.
  *
@@ -39,7 +51,7 @@ export function completePaths(name: string, extras: Array<string>): Array<string
   return paths;
 }
 
-export async function loadConfig(name: string, ...extras: Array<string>): Promise<any> {
+export async function loadConfig(name: string, ...extras: Array<string>): Promise<ConfigData> {
   const paths = completePaths(name, extras);
 
   for (const p of paths) {
diff --git a/src/config/type/Stream.ts b/src/config/type/Stream.ts
index 07147cf..884a256 100644
--- a/src/config/type/Stream.ts
+++ b/src/config/type/Stream.ts
@@ -20,4 +20,3 @@ export const streamType = new YamlType('!stream', {
     return Reflect.get(process, name);
   },
 });
-
diff --git a/src/index.ts b/src/index.ts
index e3f135f..d82fcf8 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -18,6 +18,7 @@ const MODES_LIST: Array<string> = [MODES.check, MODES.fix, MODES.list];
 
 const STATUS_SUCCESS = 0;
 const STATUS_ERROR = 1;
+const STATUS_MAX = 255;
 
 export async function main(argv: Array<string>): Promise<number> {
   const { args, mode } = parseArgs(argv);
@@ -43,7 +44,7 @@ export async function main(argv: Array<string>): Promise<number> {
   });
 
   const rules = await loadRules(args.rules, ctx);
-  const activeRules = await resolveRules(rules, args as any);
+  const activeRules = await resolveRules(rules, args);
 
   if (mode === 'list') {
     logger.info({ rules: activeRules }, 'listing active rules');
@@ -61,7 +62,7 @@ export async function main(argv: Array<string>): Promise<number> {
   if (ctx.errors.length > 0) {
     logger.error({ count: ctx.errors.length, errors: ctx.errors }, 'some rules failed');
     if (args.count) {
-      return Math.min(ctx.errors.length, 255);
+      return Math.min(ctx.errors.length, STATUS_MAX);
     } else {
       return STATUS_ERROR;
     }
diff --git a/src/parser/YamlParser.ts b/src/parser/YamlParser.ts
index a029fd4..be2435e 100644
--- a/src/parser/YamlParser.ts
+++ b/src/parser/YamlParser.ts
@@ -4,7 +4,7 @@ import { CONFIG_SCHEMA } from '../config/schema';
 import { Parser } from '../parser';
 
 export class YamlParser implements Parser {
-  dump(...data: Array<any>): string {
+  public dump(...data: Array<any>): string {
     const docs: Array<any> = [];
     for (const doc of data) {
       const part = safeDump(doc, {
@@ -15,7 +15,7 @@ export class YamlParser implements Parser {
     return docs.join('\n---\n\n');
   }
 
-  parse(body: string): Array<any> {
+  public parse(body: string): Array<any> {
     const docs: Array<any> = [];
     safeLoadAll(body, (doc: any) => docs.push(doc), {
       schema: CONFIG_SCHEMA,
diff --git a/src/rule.ts b/src/rule.ts
index 80814c7..bbc6a3e 100644
--- a/src/rule.ts
+++ b/src/rule.ts
@@ -1,12 +1,12 @@
 import { ValidateFunction } from 'ajv';
 import { applyDiff, diff } from 'deep-diff';
 import { JSONPath } from 'jsonpath-plus';
-import { cloneDeep, Dictionary, intersection, isNil } from 'lodash';
+import { cloneDeep, defaultTo, Dictionary, intersection, isNil } from 'lodash';
 import { LogLevel } from 'noicejs';
 
 import { YamlParser } from './parser/YamlParser';
 import { readFileSync } from './source';
-import { isNilOrEmpty } from './utils';
+import { ensureArray, isNilOrEmpty } from './utils';
 import { friendlyError } from './utils/ajv';
 import { Visitor } from './visitor';
 import { VisitorContext } from './visitor/VisitorContext';
@@ -40,11 +40,77 @@ export interface RuleSource {
   rules: Array<RuleData>;
 }
 
-export function ensureArray<T>(val: Array<T> | undefined): Array<T> {
-  if (isNil(val)) {
-    return [];
-  } else {
-    return Array.from(val);
+export interface RuleResult extends VisitorResult {
+  rule: Rule;
+}
+
+export class Rule implements RuleData, Visitor<RuleResult> {
+  public readonly check: ValidateFunction;
+  public readonly desc: string;
+  public readonly filter?: ValidateFunction;
+  public readonly level: LogLevel;
+  public readonly name: string;
+  public readonly select: string;
+  public readonly tags: Array<string>;
+
+  constructor(data: RuleData) {
+    this.desc = data.desc;
+    this.level = data.level;
+    this.name = data.name;
+    this.select = defaultTo(data.select, '$');
+    this.tags = Array.from(data.tags);
+
+    // copy schema objects
+    this.check = cloneDeep(data.check);
+    if (!isNil(data.filter)) {
+      this.filter = cloneDeep(data.filter);
+    }
+  }
+
+  public async pick(ctx: VisitorContext, root: any): Promise<Array<any>> {
+    const scopes = JSONPath({
+      json: root,
+      path: this.select,
+    });
+
+    if (isNil(scopes) || scopes.length === 0) {
+      ctx.logger.debug('no data selected');
+      return [];
+    }
+
+    return scopes;
+  }
+
+  public async visit(ctx: VisitorContext, node: any): Promise<RuleResult> {
+    ctx.logger.debug({ item: node, rule: this }, 'visiting node');
+
+    const check = ctx.compile(this.check);
+    const filter = this.compileFilter(ctx);
+    const errors: Array<VisitorError> = [];
+    const result: RuleResult = {
+      changes: [],
+      errors,
+      rule: this,
+    };
+
+    if (filter(node)) {
+      ctx.logger.debug({ item: node }, 'checking item');
+      if (!check(node) && !isNil(check.errors) && check.errors.length > 0) {
+        ctx.error(...Array.from(check.errors).map(friendlyError));
+      }
+    } else {
+      ctx.logger.debug({ errors: filter.errors, item: node }, 'skipping item');
+    }
+
+    return result;
+  }
+
+  protected compileFilter(ctx: VisitorContext): ValidateFunction {
+    if (isNil(this.filter)) {
+      return () => true;
+    } else {
+      return ctx.compile(this.filter);
+    }
   }
 }
 
@@ -75,7 +141,7 @@ export async function loadRules(paths: Array<string>, ctx: VisitorContext): Prom
         ctx.addSchema(data.name, data.definitions);
       }
 
-      rules.push(...data.rules.map((data: RuleData) => new Rule(data)));
+      rules.push(...data.rules.map((it: RuleData) => new Rule(it)));
     }
   }
 
@@ -149,78 +215,3 @@ export async function visitRules(ctx: VisitorContext, rules: Array<Rule>, data:
 
   return ctx;
 }
-
-export interface RuleResult extends VisitorResult {
-  rule: Rule;
-}
-
-export class Rule implements RuleData, Visitor<RuleResult> {
-  public readonly check: ValidateFunction;
-  public readonly desc: string;
-  public readonly filter?: ValidateFunction;
-  public readonly level: LogLevel;
-  public readonly name: string;
-  public readonly select: string;
-  public readonly tags: string[];
-
-  constructor(data: RuleData) {
-    this.desc = data.desc;
-    this.level = data.level;
-    this.name = data.name;
-    this.select = data.select || '$';
-    this.tags = Array.from(data.tags);
-
-    // copy schema objects
-    this.check = cloneDeep(data.check);
-    if (!isNil(data.filter)) {
-      this.filter = cloneDeep(data.filter);
-    }
-  }
-
-  public async pick(ctx: VisitorContext, root: any): Promise<Array<any>> {
-    const scopes = JSONPath({
-      json: root,
-      path: this.select,
-    });
-
-    if (isNil(scopes) || scopes.length === 0) {
-      ctx.logger.debug('no data selected');
-      return [];
-    }
-
-    return scopes;
-  }
-
-  public async visit(ctx: VisitorContext, node: any): Promise<RuleResult> {
-    ctx.logger.debug({ item: node, rule: this }, 'visiting node');
-
-    const check = ctx.compile(this.check);
-    const filter = this.compileFilter(ctx);
-    const errors: Array<VisitorError> = [];
-    const result: RuleResult = {
-      changes: [],
-      errors,
-      rule: this,
-    };
-
-    if (filter(node)) {
-      ctx.logger.debug({ item: node }, 'checking item');
-      if (!check(node) && check.errors && check.errors.length) {
-        const errors = Array.from(check.errors);
-        ctx.error(...errors.map(friendlyError));
-      }
-    } else {
-      ctx.logger.debug({ errors: filter.errors, item: node }, 'skipping item');
-    }
-
-    return result;
-  }
-
-  protected compileFilter(ctx: VisitorContext): ValidateFunction {
-    if (isNil(this.filter)) {
-      return () => true;
-    } else {
-      return ctx.compile(this.filter);
-    }
-  }
-}
diff --git a/src/utils/ajv/index.ts b/src/utils/ajv/index.ts
index 5296b89..ff02b66 100644
--- a/src/utils/ajv/index.ts
+++ b/src/utils/ajv/index.ts
@@ -1,4 +1,5 @@
 import { ErrorObject } from 'ajv';
+import { isNil } from 'lodash';
 
 import { VisitorError } from '../../visitor/VisitorError';
 
@@ -13,9 +14,9 @@ export function friendlyError(err: ErrorObject): VisitorError {
 }
 
 export function friendlyErrorMessage(err: ErrorObject): string {
-  if (err.message) {
-    return `${err.dataPath} ${err.message}`;
-  } else {
+  if (isNil(err.message)) {
     return `${err.dataPath} ${err.keyword}`;
+  } else {
+    return `${err.dataPath} ${err.message}`;
   }
 }
diff --git a/src/utils/index.ts b/src/utils/index.ts
index d2795a4..1364aed 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -1,3 +1,13 @@
+import { isNil } from 'lodash';
+
 export function isNilOrEmpty(val: Array<unknown> | null | undefined): val is Array<unknown> {
   return (Array.isArray(val) && val.length > 0);
 }
+
+export function ensureArray<T>(val: Array<T> | undefined): Array<T> {
+  if (isNil(val)) {
+    return [];
+  } else {
+    return Array.from(val);
+  }
+}
diff --git a/src/visitor/VisitorContext.ts b/src/visitor/VisitorContext.ts
index f3a4e31..0b7b797 100644
--- a/src/visitor/VisitorContext.ts
+++ b/src/visitor/VisitorContext.ts
@@ -20,20 +20,20 @@ export class VisitorContext implements VisitorContextOptions, VisitorResult {
   public readonly innerOptions: RuleOptions;
 
   protected readonly ajv: Ajv.Ajv;
-  protected readonly _changes: Array<any>;
-  protected readonly _errors: Array<VisitorError>;
+  protected readonly changeBuffer: Array<any>;
+  protected readonly errorBuffer: Array<VisitorError>;
 
   public get changes(): ReadonlyArray<any> {
-    return this._changes;
+    return this.changeBuffer;
   }
 
   public get errors(): ReadonlyArray<VisitorError> {
-    return this._errors;
+    return this.errorBuffer;
   }
 
   constructor(options: VisitorContextOptions) {
-    this._changes = [];
-    this._errors = [];
+    this.changeBuffer = [];
+    this.errorBuffer = [];
 
     this.ajv = new Ajv({
       coerceTypes: options.innerOptions.coerce,
@@ -49,12 +49,12 @@ export class VisitorContext implements VisitorContextOptions, VisitorResult {
       logWithLevel(this.logger, err.level, err.data, err.msg);
     }
 
-    this._errors.push(...errors);
+    this.errorBuffer.push(...errors);
   }
 
   public mergeResult(other: VisitorResult): this {
-    this._changes.push(...other.changes);
-    this._errors.push(...other.errors);
+    this.changeBuffer.push(...other.changes);
+    this.errorBuffer.push(...other.errors);
     return this;
   }
 
@@ -69,7 +69,7 @@ export class VisitorContext implements VisitorContextOptions, VisitorResult {
     });
 
     this.ajv.addSchema({
-      '$id': name,
+      $id: name,
       definitions: schema,
     });
   }
diff --git a/test/TestRule.ts b/test/TestRule.ts
index b12f58b..681171d 100644
--- a/test/TestRule.ts
+++ b/test/TestRule.ts
@@ -6,26 +6,26 @@ import { makeSelector, resolveRules, Rule, visitRules } from '../src/rule';
 import { VisitorContext } from '../src/visitor/VisitorContext';
 
 const TEST_RULES = [new Rule({
-  name: 'foo',
+  check: {},
   desc: '',
   level: 'info',
+  name: 'foo',
+  select: '$',
   tags: ['all', 'foo'],
-  check: {},
-  select: '$',
 }), new Rule({
+  check: {},
+  desc: '',
+  level: 'warn',
   name: 'bar',
-  desc: '',
-  level: 'warn',
-  tags: ['all', 'test'],
-  check: {},
   select: '$',
+  tags: ['all', 'test'],
 }), new Rule({
-  name: 'bin',
+  check: {},
   desc: '',
   level: 'warn',
-  tags: ['all', 'test'],
-  check: {},
+  name: 'bin',
   select: '$',
+  tags: ['all', 'test'],
 })];
 
 describe('rule resolver', () => {
@@ -102,21 +102,21 @@ describe('rule resolver', () => {
 describe('rule visitor', () => {
   it('should only call visit for selected items', async () => {
     const ctx = new VisitorContext({
-      logger: new ConsoleLogger(),
       innerOptions: {
         coerce: false,
         defaults: false,
         mutate: false,
-      }
+      },
+      logger: new ConsoleLogger(),
     });
     const data = {};
     const rule = new Rule({
-      name: 'foo',
+      check: {},
       desc: '',
       level: 'info',
-      tags: [],
+      name: 'foo',
       select: '$',
-      check: {},
+      tags: [],
     });
 
     const mockRule = mock(rule);
@@ -143,12 +143,12 @@ describe('rule visitor', () => {
     });
     const data = {};
     const rule = new Rule({
-      name: 'foo',
+      check: {},
       desc: '',
       level: 'info',
-      tags: [],
+      name: 'foo',
       select: '$',
-      check: {},
+      tags: [],
     });
 
     const mockRule = mock(rule);
diff --git a/test/harness.ts b/test/harness.ts
index abc3b64..0b06326 100644
--- a/test/harness.ts
+++ b/test/harness.ts
@@ -1,3 +1,3 @@
-import sourceMapSupport from 'source-map-support'
+import sourceMapSupport from 'source-map-support';
 
-sourceMapSupport.install()
+sourceMapSupport.install();
diff --git a/test/parser/TestYamlParser.ts b/test/parser/TestYamlParser.ts
index a64b380..1ff4097 100644
--- a/test/parser/TestYamlParser.ts
+++ b/test/parser/TestYamlParser.ts
@@ -5,10 +5,10 @@ import { YamlParser } from '../../src/parser/YamlParser';
 describe('yaml parser', () => {
   describe('dump documents', () => {
     it('should dump multiple documents', () => {
-    const parser = new YamlParser();
-    const data = parser.dump({}, {});
+      const parser = new YamlParser();
+      const data = parser.dump({}, {});
 
-    expect(data).to.contain('---');
+      expect(data).to.contain('---');
     });
   });
 
@@ -20,7 +20,7 @@ foo: {}
 ---
 bar: {}
       `);
-      
+
       expect(Array.isArray(data)).to.equal(true);
       expect(data.length).to.equal(2);
     });
diff --git a/test/utils/ajv/TestFriendlyErrors.ts b/test/utils/ajv/TestFriendlyErrors.ts
index d74afa3..481c0b8 100644
--- a/test/utils/ajv/TestFriendlyErrors.ts
+++ b/test/utils/ajv/TestFriendlyErrors.ts
@@ -5,10 +5,10 @@ import { friendlyError } from '../../../src/utils/ajv';
 describe('friendly errors', () => {
   it('should have a message', () => {
     const err = friendlyError({
-      keyword: 'test',
       dataPath: 'test-path',
-      schemaPath: 'test-path',
+      keyword: 'test',
       params: { /* ? */ },
+      schemaPath: 'test-path',
     });
     expect(err.msg).to.not.equal('');
   });