diff --git a/README.md b/README.md
index 38f7e35..97de200 100644
--- a/README.md
+++ b/README.md
@@ -14,3 +14,15 @@ main fields of the resource
 
 ### meta
 meta fields of the resource, such as created\_at, created\_by
+
+
+## TODO
+- fix eslint (migrate to latest)
+- explain it is middleware first architecture
+- explain how to create a middleware
+- explain module vs middleware
+- explain how to create a modules
+- explain create module to be use as middleware or in middleware
+- explain how to branch
+- explain how to detour (await next)
+- how to handle error. define midduleware to handle route "ERR" and throw error by this.next(this.web.Error(status, message, headers))
diff --git a/index.js b/index.js
index cebd4b8..66ef387 100755
--- a/index.js
+++ b/index.js
@@ -1,6 +1,7 @@
 #!/usr/bin/env node
 
-// In case picos was installed globally
+// In case picos was installed globally,
+// dynamically updates where Node.js looks for modules without changing any permanent configuration
 const NP = process.env.NODE_PATH || ''
 process.env.NODE_PATH = (NP ? NP + ':' : NP) + process.cwd() + '/node_modules'
 require('module').Module._initPaths()
@@ -18,14 +19,20 @@ function run(opt, cb){
 // Is run from cmd?
 if (require.main === module) {
 	const args = require('pico-args')
-	const opt = args.parse({
-		service: ['service/index', 'path to service script'],
+	const params =  {
+		service: ['', 'path to the service script, e.g: "service/index.json"'],
 		s: '@service',
-		mod: ['mod/', 'module path'],
-		m: '@service',
-		ratelimit: [64, 'ratelimit'],
-		r: '@ratelimit'
-	})
+		mod: ['mod/', 'path to the module folder'],
+		m: '@mod',
+		ratelimit: [64, 'ratelimit the concurrent requests'],
+		r: '@ratelimit',
+		help: [false, 'Usage'],
+		h: '@help',
+	}
+	const opt = args.parse(params)
+	if (!opt.service || opt.help){
+		return args.usage(params)
+	}
 	run(opt, err => {
 		if (err) return console.error(err)
 	})
diff --git a/mod/util.js b/mod/util.js
index 696afe1..9497cec 100644
--- a/mod/util.js
+++ b/mod/util.js
@@ -63,7 +63,7 @@ module.exports = {
 
 	routerByRSC: (rsc, prefix = '/i') => async function(method, params) {
 		const rs = rsc[params.rsc]
-		if (!rs) return this.next(`unsupprted resource: ${params.rsc}`)
+		if (!rs) return this.next(null, `ERR/RESOURCE-NOT-FOUND/${params.rsc}`)
 		const idx = params.i ? prefix : ''
 		const name = `${method}/${params.rsc}${idx}`
 		await this.next(null, name, Object.assign({
@@ -75,13 +75,13 @@ module.exports = {
 
 	input: spec => function(input, output, ext) {
 		const err = pObj.validate(spec, input, output, ext)
-		if (err) return this.next(`invalid params [${err}]`)
+		if (err) return this.next(null, `ERR/INVALID-INPUT/[${err}]`)
 		return this.next()
 	},
 
 	inputNoCurry(input, spec, output, ext) {
 		const err = pObj.validate(spec, input, output, ext)
-		if (err) return this.next(`invalid params [${err}]`)
+		if (err) return this.next(null, `ERR/INVALID-INPUT/[${err}]`)
 		return this.next()
 	},
 
diff --git a/mod/web.js b/mod/web.js
index a593888..0ff3f96 100644
--- a/mod/web.js
+++ b/mod/web.js
@@ -9,6 +9,10 @@ const HAS_DATA = obj => obj && (Array.isArray(obj) || Object.keys(obj).length)
 const CREATE_BODY = (body, meta) => JSON.stringify(Object.assign({}, meta, {body}))
 const GET_CONTENT_TYPE = (value = '') => value.split(';')[0].trim().toLowerCase()
 
+function Error(status, message, headers){
+	return {status, message, headers}
+}
+
 module.exports = {
 	setup(cfg, rsc, paths){
 		const cors = cfg.cors
@@ -33,6 +37,8 @@ module.exports = {
 			const url = URL.parse(req.url, 1)
 			this.go(url.pathname, {req, res, url})
 		}).listen(cfg.port, cfg.host, () => process.stdout.write(`listening to ${cfg.host}:${cfg.port}\n`))
+
+		return {Error}
 	},
 
 	queryParser(req, query){
@@ -126,15 +132,11 @@ module.exports = {
 					res.writeHead(head.status || 200, Object.assign(headers, head.headers))
 					res.end(createBody(output, meta))
 				} else {
-					res.writeHead(head.status || 200, head.headers)
+					res.writeHead(head.status || 204, head.headers)
 					res.end()
 				}
 			} catch(exp) {
-				if (exp.isAxiosError){
-					console.error(exp.toJSON())
-				} else {
-					console.error(exp)
-				}
+				console.error('web error', exp.isAxiosError ? exp.toJSON() : exp)
 				// exp in head format? {status, headers, message}
 				const status = exp.status || 500
 				res.writeHead(status, exp.headers)
diff --git a/package.json b/package.json
index e638b9d..20335b7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "picos",
-  "version": "0.10.9",
+  "version": "0.11.0",
   "description": "pico api service",
   "main": "index.js",
   "bin": {
@@ -13,11 +13,11 @@
     "randexp": "^0.5.3"
   },
   "scripts": {
-    "start": "node index.js -s okapi/index.js",
+    "start": "node index.js -s test/service.json",
     "test": "node test/index.js",
     "test:cp": "jscpd --ignore 'node_modules,test' .",
-    "lint": "eslint . --ext .js",
-    "lint:fix": "eslint . --ext .js --fix"
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix"
   },
   "repository": {
     "type": "git",
diff --git a/src/book.js b/src/book.js
index fcaac78..f823f6b 100644
--- a/src/book.js
+++ b/src/book.js
@@ -9,21 +9,21 @@ pico.ajax = psUtil.ajax
 
 const fopt = {encoding: 'utf8'}
 
-let CWD
+let PD
 
 /**
- * Get current working directory
+ * Get picos directory. the PD is a abs, none symbolic link and contains the picos index.js
  *
  * @param {Function} cb - call back
  *
  * @returns {void} - undefined
  */
-function getWD(cb){
-	if (CWD) return cb(CWD)
-	fs.readlink(symPath, (err, realPath) => {
-		if (err) realPath = symPath
-		CWD = path.dirname(realPath)
-		cb(CWD)
+function getPD(cb){
+	if (PD) return cb(PD)
+	fs.readlink(symPath, (err, relPath) => {
+		if (err) PD = symPath
+		else PD = path.resolve(symPath, realPath)
+		cb(path.dirname(PD))
 	})
 }
 
@@ -76,22 +76,20 @@ function readBook(wd, index, cb){
 	readPages(wd, [index], [], (err, res) => {
 		if (err) return cb(err)
 		if (!res.length) return cb(`not found: ${index}`)
-		if (!res[0].charAt) return cb(null, res)
+		if (!Array.isArray(res[0])) return cb(null, res)
 		readPages(wd, res[0], [], cb)
 	})
 }
 
 module.exports = {
 	open(bname, cb){
-		getWD(cwd => {
-			const bpath = getPath(cwd, bname)
-			const wd = path.dirname(bpath)
-			const name = path.basename(bpath)
-			readBook(wd, name, (err, book) => {
-				if (err) return cb(err)
-				cb(null, pObj.extends({}, book, {flat: 1}))
-			})
+		const bpath = getPath('.', bname)
+		const wd = path.dirname(bpath)
+		const name = path.basename(bpath)
+		readBook(wd, name, (err, book) => {
+			if (err) return cb(err)
+			cb(null, pObj.extends({}, book, {flat: 1}))
 		})
 	},
-	getWD
+	getPD
 }
diff --git a/src/pipeline.js b/src/pipeline.js
index ffb1475..bcba2a3 100644
--- a/src/pipeline.js
+++ b/src/pipeline.js
@@ -44,7 +44,7 @@ function _host(radix, libs, routes, threshold){
 	 */
 	async function next(err, named, data = this.data || {}){
 		if (err) {
-			overtime.decr(1)
+			overtime.decr()
 			throw err
 		}
 		if (null != named) {
@@ -53,7 +53,11 @@ function _host(radix, libs, routes, threshold){
 			let route = routes[key]
 			if (!route) {
 				route = named && routes[ERROR_ROUTE]
-				if (!route) return console.error(`route[${named}] not found`)
+				if (!route) {
+					// no console.error if named is an empty string
+					named && console.error(`route[${named}] not found`)
+					return
+				}
 			}
 			overtime.incr()
 			return next.call(Object.assign({}, libs, {named, params, next, route, data, ptr: 0}))
@@ -61,7 +65,7 @@ function _host(radix, libs, routes, threshold){
 
 		const middleware = this.route[this.ptr++]
 		if (!middleware) {
-			return overtime.decr(3)
+			return overtime.decr()
 		}
 
 		const args = middleware.slice(1).map(key => {
diff --git a/test/util.js b/test/util.js
index 414492d..a807f5d 100644
--- a/test/util.js
+++ b/test/util.js
@@ -18,6 +18,6 @@ module.exports = {
 	},
 	sayNow(out){
 		Object.assign(out, {now: Date.now()})
-		this.next()
+		return this.next()
 	}
 }