diff --git a/README.md b/README.md
index 7b00ca1..08f7d1b 100644
--- a/README.md
+++ b/README.md
@@ -10,14 +10,14 @@ cargo install --git https://git.hatter.ink/hatter/runrs runrs
 
 Environment variables
 
-| Env Key       | Env Value                                                     |
-|---------------|---------------------------------------------------------------|
-| `HOME`        | User home, default by OS system                               |
-| `RUNRS_SKIP_CACHE`  | Skip compiled cached file , turn on `true`, `yes`, `on` or `1` |
-| `RUNRS_REBUILD` | Force rebuild                                                 |
-| `RUNRS_SILENT_BUILD` | Build new binary in silent mode                               |
-| `RUNRS_RUST_SCRIPT` | `rust_script` command line bin file                           |
-| `RUNRS_MAX_SCRIPT_LEN` | Max script length                                             |
+| Env Key       | Env Value                                                            |
+|---------------|----------------------------------------------------------------------|
+| `HOME`        | User home, default by OS system                                      |
+| `RUNRS_SKIP_CACHE`  | Skip compiled cached file, `bool` , turn on `true`, `yes`, `on` or `1` |
+| `RUNRS_REBUILD` | Force rebuild, `bool`                                                  |
+| `RUNRS_SILENT_BUILD` | Build new binary in silent mode, `bool`                                |
+| `RUNRS_RUST_SCRIPT` | `rust_script` command line bin file                                  |
+| `RUNRS_MAX_SCRIPT_LEN` | Max script length, default 1MB                                       |
 
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