Herdr

Herdr

Herdr organizes terminals into workspaces, tabs, and panes, recognizes coding agents running inside panes, and exposes the current session through the herdr CLI.

Before issuing any control command, verify that this agent is running inside a Herdr-managed pane:

test "${HERDR_ENV:-}" = 1

If the check fails, say that you are not running inside Herdr and stop. Do not inspect or control the focused Herdr session from outside Herdr.

When the check passes, the herdr binary in PATH talks to the current session. Use it to inspect neighboring work, create terminal layout, start agents and commands, read output, and wait for state changes.

Learn the current CLI

The installed binary is the authority for command syntax. Start with:

herdr --help

Then print the relevant command group by running the group without a subcommand:

herdr agent
herdr pane
herdr workspace
herdr tab
herdr worktree
herdr terminal
herdr notification
herdr integration
herdr session
herdr machine

Do not run bare herdr for discovery; it launches or attaches the TUI. Do not probe a mutating nested command by omitting arguments. Commands such as herdr workspace create are valid with defaults and will execute.

Most control commands return JSON. Read identifiers and state from those responses instead of predicting them.

Understand layout, panes, and agents

Choose the primitive that matches the job:

• Workspace, tab, and pane topology organize terminal locations.
• Pane commands control raw terminals, shells, tests, servers, input, and output.
• Agent commands control the recognized coding agent currently occupying a pane.

A pane exists whether or not it contains an agent. agent start requires an existing available shell pane and never creates, splits, or moves layout. Use pane commands for ordinary processes. Use agent commands when Herdr must validate agent identity or interpret idle, working, blocked, done, and unknown lifecycle states.

Agent commands accept either a unique live agent name or the pane ID currently hosting that agent. They do not accept terminal IDs or bare agent-kind labels. Names must match [a-z][a-z0-9_-]{0,31} and be unique among live agents. A name follows the current pane occupant and is cleared when that agent exits, is released, or is replaced.

idle and done both mean the agent is ready for input. The CLI/API uses the server's seen state to distinguish them; explicit focus commands mark the target seen, while reads do not. Each TUI client tracks viewed completions independently, so its Done badge can differ from the CLI or another client's badge. blocked means Herdr recognized an approval or question UI. unknown means an agent is present but Herdr cannot classify it confidently; it does not prove completion.

Use IDs and caller context

Public IDs are opaque stable handles:

• workspace: w1
• tab: w1:t1
• pane: w1:p1

Closed tab and pane IDs are not reused. A pane moved into another workspace receives a new workspace-qualified pane ID. After pane move, continue with .result.move_result.pane.pane_id or the live agent name. The old value is reported as .result.move_result.previous_pane_id; only the moved process's inherited caller context keeps resolving that old ID, so do not use it as a general agent target.

Herdr injects the caller's context into each managed pane:

printf '%s\n' "$HERDR_WORKSPACE_ID" "$HERDR_TAB_ID" "$HERDR_PANE_ID"

Prefer --current when a pane command should target the calling pane. An omitted pane split target uses the calling pane when HERDR_PANE_ID is available, otherwise the focused pane. Other commands may use the UI-focused pane, which can belong to the user or another client.

Discover live state with:

herdr workspace list
herdr tab list --workspace "$HERDR_WORKSPACE_ID"
herdr pane current --current
herdr pane list --workspace "$HERDR_WORKSPACE_ID"
herdr agent list

Creation responses expose the IDs to use next. workspace create returns .result.workspace, .result.tab, and .result.root_pane. tab create returns .result.tab and .result.root_pane. pane split returns the new pane as .result.pane.

IDs and live agent names are scoped to one server. Two saved SSH machines can both have w1:p1 or an agent named reviewer. Selecting a machine in the TUI does not retarget commands running in your pane: without --machine, they still use the inherited session and socket context.

To control a saved SSH machine, use the same global prefix for discovery and every later command:

herdr --machine <label-or-id> agent list
herdr --machine <label-or-id> pane list
herdr --machine <label-or-id> agent prompt <remote-agent-name> "Reply with your current status." --wait --timeout 120000

The selector must be an enabled saved profile ID or a unique, case-sensitive label, not an arbitrary SSH hostname. Commands use that profile's remote session without an open TUI. Do not combine --machine with --session or --remote. Discover IDs on that machine; inherited local IDs and --current do not identify remote panes.

Both installations must support machine API forwarding, and the remote server must already be running and API-compatible. Forwarding never installs, starts, or restarts a server and never falls back to Local. Local configuration, session management, installation commands, and interactive attachment are not forwarded. Remote worktree paths must be absolute, ~, or start with ~/; plugin link paths must be absolute. A connection failure does not prove a mutation was not applied: inspect remote state before retrying.

herdr machine list lists saved connection profiles, not a cross-machine pane inventory; add --json for scripts. Only add, remove, enable, or disable profiles when the user asks. Removing a profile disconnects the client but does not stop remote sessions. Adding a machine uses the remote default session unless --remote-session is explicitly supplied. Setup asks before stopping an incompatible server and defaults to No; do not approve replacement without the user's consent. Experimental handoff is not part of machine add.

Start and coordinate an agent

Default to a sibling pane in the current tab and the current working directory. Do not create a workspace, tab, worktree, or different cwd unless the user explicitly requests that topology or location.

Honor a direction requested by the user. Otherwise inspect the caller pane:

herdr pane layout --pane "$HERDR_PANE_ID"

Split a wide pane to the right and a narrow or tall pane down. Avoid repeated same-direction splits that create unusably narrow columns or short rows. Keep the user's focus in the calling pane and explicitly preserve the caller's working directory:

herdr pane split --current --direction right --cwd "$PWD" --no-focus

Replace right with down when appropriate. Read the new pane ID from .result.pane.pane_id.

An available shell pane must be at its interactive prompt, with the shell itself in the foreground and no foreground command, editor, or agent running. Start a supported agent in that pane with a useful unique name:

herdr agent start reviewer --kind codex --pane <returned-pane-id>

Use the kind requested by the user. Run herdr agent to inspect the installed kind list and options. Pass native agent arguments only after --:

herdr agent start reviewer --kind codex --pane <returned-pane-id> -- <agent-args...>

A successful agent start returns only after Herdr detects the expected agent in the same pane and considers it ready for interactive input. If the agent is blocked during startup, the command returns agent_not_ready immediately but keeps the name available for agent read and agent send-keys. Wait until the agent becomes idle before prompting it. Startup defaults to a 30-second timeout.