Chat

aster in a repository opens the chat TUI. Everything else is optional flags on top of it.

aster                                # TUI in the current repo
aster "why does the build fail?"     # one-shot: print and exit (--print / -p)
echo "explain this repo" | aster     # piped stdin is the prompt
aster --continue                     # resume this repo's latest session
aster --resume [ID]                  # pick a session, or resume one by id
aster --session ID "next question"   # persist into a named session
aster --messages-json history.json   # caller owns the transcript (- for stdin)
aster --compact --messages-json h.json   # fold history into a summary, print it
aster --stream                       # NDJSON events out, approval replies in
aster --no-tools                     # plain chat, no read/search/edit
aster --no-mcp                       # start instantly; /mcp connects later
aster --allow-edits                  # let a scripted turn edit files
aster --permission-mode plan|manual|auto|edit|yolo

Keys

Key	Does
`enter`	Send; while a turn runs it queues the message
`esc`	Interrupt the running turn; `esc esc` quits
`shift+tab`	Step to the next permission mode
`ctrl+j`	Newline without sending
`ctrl+o`	The `/switch` panel
`@`	Mention a repo file; images and documents attach as content
`↑ ↓`	Move the cursor, then step through past messages

Slash commands

Command	Does
`/switch`	Thinking, mode, effort, model, provider in one panel
`/model [id]`, `/m`	Switch model or open the picker
`/provider [id\|url]`, `/p`	Switch endpoint, then pick a model
`/mode [name]`	plan, manual, auto, edit, yolo
`/effort [level]`	Set or cycle the reasoning budget
`/thinking`	Print the model’s thinking in full or not
`/yolo`	Toggle yolo (guardrails off, red theme)
`/mom [resume]`	Show the mom.yaml routing state; `resume` re-arms it after a manual `/model`
`/resume`, `/r`	Reopen a saved session
`/clear`, `/c`	Start fresh
`/compact`	Fold earlier turns into a summary
`/status`	Session, model, context, token usage
`/diff`, `/d`	Uncommitted changes
`/mcp`	MCP servers and their tools; connects them if `--no-mcp` skipped it
`/skills`	Pick a skill to load
`/memory`	What Aster remembers here
`/theme`	Open the theme picker; previews live as you arrow through
`/welcome`	Show or hide the session header, saved to `ui.welcome`
`/goal <condition>`	Loop turns until a judge model says the condition is met
`/help`, `/quit`	The list above; exit

Installed skills that declare a command also appear as slash commands, for example /write-tests.

Themes

/theme opens a picker that previews live as you arrow through; Enter saves the choice to ui.theme in aster.yaml. Built-ins include dark, light, midnight, forest, dracula, catppuccin, nord, gruvbox, solarized, synthwave, github-dark, monokai, one-dark, aster-ocean, aster-ember, and aster-orchid. Custom themes are YAML files dropped into ~/.aster/themes/ or .aster/themes/; they appear in the picker on the next launch.

Streaming for tools

--stream emits one JSON object per line. The desktop app and the VS Code extension both consume this format, and it is stable output, not a log:

aster --stream "summarize the failing test"

Approval prompts arrive as events on stdout; reply on stdin to approve or deny, which is how headless front-ends gate edits.

Start

Using Aster

Extending

Automation

Workflows

Surfaces

Reference

Keys

Slash commands

Themes

Streaming for tools

​Keys

​Slash commands

​Themes

​Streaming for tools

Keys

Slash commands

Themes

Streaming for tools