| Command | Sent by | Type | Data | Description |
| CMDDO | client | 0 | string | JE executes sentence |
| CMDDOZ | JE | error | none | JE finished with sentence |
| CMDIN | JE | 0 | prompt | J requests keyboard input |
| CMDINZ | client | 0 | input | JE resumes execution |
| CMDWD | JE | x | array | client runs 11!:x request |
| CMDWDZ | client | WDZ | data | JE resumes execution |
| CMDOUT | JE | OUT | string | output for display |
| CMDBRK | client | 0 | none | JE interrupts execution |
| CMDGET | client | 0 | name | JE replies with CMDGETZ |
| CMDGETZ | JE | error | array | value in 3!:1 format |
| CMDSETN | client | 0 | name | sets name for CMDSET |
| CMDSET | client | 0 | array | sets name with 3!:1 value |
| CMDSETZ | JE | error | none | result of set |
| CMDEXIT | JE | code | none | 2!:55 code |