/steer first tries to send guidance to an already-active run. It is for "adjust this run while it is still working" moments. If the current runtime cannot accept steering, Apus sends the message as a normal prompt instead of dropping it.

/tell is an alias of /steer. The two names are interchangeable everywhere on this page.

Current session

Use top-level /steer to target the active run for the current session:

/steer prefer the smaller patch and keep the tests focused
/tell summarize before making the next tool call

Behavior:

• Targets only the current session's active run.
• Works independently of the session's /queue mode.
• Starts a normal turn with the same message when the session is idle or the active run cannot accept steering.
• Uses the active runtime's steering path, so the model sees the guidance at the next supported runtime boundary.

Steer vs queue

/queue steer makes normal inbound messages try to steer the active run when they arrive while a run is active. /steer <message> is an explicit command that tries to inject that command's message into the active run at the next supported runtime boundary, regardless of the stored /queue setting. When that injection is not available, the command prefix is stripped and <message> continues as a normal prompt.

The explicit /steer (and /tell) command is Gateway-backed. In apus chat or apus tui --local, select /queue steer and send the guidance as a normal message; the embedded runtime applies the same steering policy without forwarding a Gateway command.

Use:

• /steer <message> when you want to guide the active run right now.
• /queue steer when you want future normal messages to steer active runs by default.
• /queue collect or /queue followup when future normal messages should wait for a later turn instead of steering the active run.
• /queue interrupt when the newest message should replace the active run instead of steering it.

For queue modes and steering boundaries, see Command queue and Steering queue.

Sub-agents

Top-level /steer targets the current session's active run. Sub-agents report back to their parent/requester session; /subagents is for visibility only.

ACP sessions

Use /acp steer when the target is an ACP harness session:

/acp steer --session agent:main:acp:codex tighten the repro

ACP harness sessions cannot accept input mid-turn. /acp steer queues the instruction and runs it after the active turn finishes; use /acp cancel first to stop work in progress. See ACP controls.

See ACP agents for ACP session selection and runtime behavior.

Related

• Slash commands
• Command queue
• Steering queue
• Sub-agents