diff --git a/README.md b/README.md
index d133f3a..ee71225 100644
--- a/README.md
+++ b/README.md
@@ -20,10 +20,16 @@ $ cd utsusemi
 $ npm install
 ```
 
-### :pencil: STEP 2. Edit config
+### :pencil: STEP 2. Set environment variables OR Edit config.yml
+
+Set environment variables.
+
+OR
 
 Copy [`config.example.yml`](config.example.yml) to `config.yml`. And edit.
 
+Environment / config.yml Document is [here](docs/env.md) :book: .
+
 ### :rocket: STEP 3. Deploy to AWS
 
 ```console
@@ -34,8 +40,7 @@ And get endpoints URL and `UtsusemiWebsiteURL`
 
 #### :bomb: Destroy utsusemi
 
-1. Call API `/delete?path=/`
-2. Run following command.
+Run following command.
 
 ```console
 $ AWS_PROFILE=XXxxXXX npm run destroy
diff --git a/config.example.yml b/config.example.yml
index 3f50055..09a87c1 100644
--- a/config.example.yml
+++ b/config.example.yml
@@ -1,9 +1,21 @@
 ---
+# utsusemi service name
+serviceName: utsusemi
+# AWS deploy region
 region: ap-northeast-1
+# Crawl target host
 targetHost: https://opslet.com
+# Web site hosting S3 bucket name
 bucketName: utsusemi.opslet.com
+# Crawl worker process
 workerProcess: 2
+# Delay time when start worker (ms)
 workerDelay: 100
+# Crawl job threads per worker
 threadsPerWorker: 1
-# forceTrailingSlash: true
+# Change http://example.com/path/to -> http://example.com/path/to/
+forceTrailingSlash: 1
+# Use API Key when request utsusemi API
+useApiKey: 0
+# Crawler User Agent
 # crawlerUserAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 +utsusemi'
diff --git a/docs/env.md b/docs/env.md
new file mode 100644
index 0000000..c19ecd1
--- /dev/null
+++ b/docs/env.md
@@ -0,0 +1,14 @@
+# utsusemi Environment / config.yml
+
+|  | Environment | config.yml key | default |
+| --- | --- | --- | --- |
+| Service name | `UTSUSEMI_SERVICE_NAME` | `serviceName` | utsusemi |
+| AWS deploy region | `UTSUSEMI_REGION` | `region` | ap-northeast-1 |
+| Crawl target host | `UTSUSEMI_TARGET_HOST` | `targetHost` |  |
+| Web site hosting S3 bucket name | `UTSUSEMI_BUCKET_NAME` | `bucketName` |  |
+| Crawl worker process | `UTSUSEMI_WORKER_PROCESS` | `workerProcess` | 2 |
+| Delay time when start worker (ms) | `UTSUSEMI_WORKER_DELAY` | `workerDelay` | 100 |
+| Crawl job threads per worker | `UTSUSEMI_THREADS_PER_WORKER` | `threadsPerWorker` | 1 |
+| Change http://example.com/path/to -> http://example.com/path/to/ | `UTSUSEMI_FORCE_TRAILING_SLASH` | `forceTrailingSlash` | 1 |
+| Use API Key when request utsusemi API | `UTSUSEMI_USE_API_KEY` | `useApiKey` | 0 |
+| Crawler User Agent | `UTSUSEMI_CRAWLER_USER_AGENT` | `crawlerUserAgent` | `ustusemi/{version}` |
diff --git a/serverless.yml b/serverless.yml
index 86fe223..2bdba6c 100644
--- a/serverless.yml
+++ b/serverless.yml
@@ -11,11 +11,11 @@ provider:
     UTSUSEMI_TARGET_HOST: ${env:UTSUSEMI_TARGET_HOST, file(./config.yml):targetHost}
     UTSUSEMI_BUCKET_NAME: ${env:UTSUSEMI_BUCKET_NAME, file(./config.yml):bucketName}
     UTSUSEMI_WORKER_PROCESS: ${env:UTSUSEMI_WORKER_PROCESS, file(./config.yml):workerProcess, '2'}
-    UTSUSEMI_WORKER_DELAY: ${env:UTSUSEMI_WORKER_DELAY, file(./config.yml):workerDelay, '2'}
-    UTSUSEMI_THREADS_PER_WORKER: ${env:UTSUSEMI_THREADS_PER_WORKER, file(./config.yml):threadsPerWorker, '5'}
+    UTSUSEMI_WORKER_DELAY: ${env:UTSUSEMI_WORKER_DELAY, file(./config.yml):workerDelay, '100'}
+    UTSUSEMI_THREADS_PER_WORKER: ${env:UTSUSEMI_THREADS_PER_WORKER, file(./config.yml):threadsPerWorker, '1'}
     UTSUSEMI_FORCE_TRAILING_SLASH: ${env:UTSUSEMI_FORCE_TRAILING_SLASH, file(./config.yml):forceTrailingSlash, '1'}
-    UTSUSEMI_CRAWLER_USER_AGENT: ${env:UTSUSEMI_CRAWLER_USER_AGENT, file(./config.yml):crawlerUserAgent, ''}
     UTSUSEMI_USE_API_KEY: ${env:UTSUSEMI_USE_API_KEY, file(./config.yml):useApiKey, '0'}
+    UTSUSEMI_CRAWLER_USER_AGENT: ${env:UTSUSEMI_CRAWLER_USER_AGENT, file(./config.yml):crawlerUserAgent, ''}
   runtime: nodejs6.10
   stage: ${self:provider.environment.UTSUSEMI_STAGE}
   region: ${self:provider.environment.UTSUSEMI_REGION}