herdr Orchestration

The top-level agent is the controller (Codex, Claude, Fable, or another); it delegates to worker TUIs that gather evidence, draft bounded patches, run tests, and report. The controller owns assignment, state, conflict control, verification, integration, and the final user-facing answer. herdr is the substrate: each worker TUI owns a named tab, and the socket CLI (herdr …) gives the controller placement, input, screen reads, and native agent-status waits.

One worker, one named tab

Every worker gets its own tab, labeled at creation with tab create --label. The tab bar is the controller's dashboard: a labeled tab says which model is running which slice, and stays readable no matter how many workers are live.

Tabs also cost no screen area. A split pane divides the caller's screen with every worker, and on a laptop the third worker leaves every pane too narrow to read. Split a pane only when the user explicitly asks to watch a worker beside the caller.

Two names per worker, both required at launch:

• tab label — <model>: <slice>, e.g. opus: fix loops, codex: audit auth. Free text; keep it short, tab bars truncate.
• agent name — the slice as a slug, e.g. fix-loops. Must match [a-z][a-z0-9_-]{0,31} and be unique among live agents. Every agent … verb accepts it in place of a pane id.

Workers are TUIs — no headless runners

A worker is an interactive TUI — claude or codex — started with herdr agent start, which validates the agent's identity and returns only once herdr sees it ready for input. herdr's agent-state integrations hook those TUIs, so agent wait, agent list, and blocked/done detection exist only while a real TUI is on screen.

Headless runners — claude -p, codex exec, anything that streams JSON events into a pane — never report state, so waits never fire and the delegation dies silently. A worker tab filling with raw JSON event lines is a broken delegation: interrupt it (rtk herdr pane send-keys <pane_id> ctrl+c) and relaunch through agent start.

Invariants

• Scope every action to the caller workspace unless the user names another target.
• Resolve caller context from HERDR_WORKSPACE_ID, HERDR_TAB_ID, and HERDR_PANE_ID (injected into every herdr pane) before any focused-window fallback.
• Address workers by ids parsed from command JSON — agent name for agent … verbs, w2:t3 / w2:p4 for tab and pane verbs — never by guessed position.
• Pass --no-focus on every creating verb (tab create, workspace create, worktree create, pane split); use focus verbs only when the user asks.
• Retire every worker you launch when its assignment and planned integration follow-ups are finished (see Retire workers).

Preflight

Inspect the daemon, integrations, and caller context:

rtk herdr status                 # server running + socket path
rtk herdr integration status     # selected worker runtime must show `current`
rtk herdr pane current --current # caller pane / tab / workspace ids
rtk herdr agent list             # agents already running

Check/install only the integration for each selected runtime. Reuse this preflight in the same workspace while the daemon and integrations are unchanged; a new packet alone does not require repeating it.

Launch workers

Use each worker runtime's configured model unless the user requests an override. Launch is two commands: create the named tab, then start the TUI in that tab's root pane.

# 1. named tab — returns .result.tab.tab_id and .result.root_pane.pane_id
rtk herdr tab create --workspace "$HERDR_WORKSPACE_ID" --cwd "$PWD" \
  --label "opus: fix loops" --no-focus

# 2. worker TUI in that tab's root pane; native flags follow `--`
rtk herdr agent start fix-loops --kind claude --pane <root_pane_id> -- \
  --dangerously-skip-permissions "<packet>"

rtk herdr agent start audit-auth --kind codex --pane <root_pane_id> -- \
  --yolo

Capture tab_id, pane_id, and the agent name in the registry — retiring and screen reads need all three.

Claude always launches with --dangerously-skip-permissions and Codex with --yolo — workers run unattended and must not stall on permission prompts. Plan-first runs add Claude's --permission-mode plan; the flags compose (see Plan-first delegation).

agent start returns success only after herdr detects the agent ready, so a non-zero exit is the launch failure — read the tab's root pane (rtk herdr pane read <pane_id> --source visible) before retrying. Confirm the label stuck with rtk herdr tab list --workspace "$HERDR_WORKSPACE_ID"; if the tab shows a default label, restore it:

rtk herdr tab rename <tab_id> "opus: fix loops"

Sending prompts to running TUIs

Prefer passing the initial packet as launch argv (shown above) — the session starts working immediately and skips the TUI-ready race. Exception: Codex plan-first launches bare (see Plan-first delegation).

For any follow-up, use agent prompt — it submits text plus Enter atomically, honoring the pane's live bracketed-paste mode, and --wait blocks until the worker settles:

rtk herdr agent prompt fix-loops "<follow-up prompt>" --wait --timeout 300000

A trailing \n in pane send-text does not submit — a TUI renders it as a soft newline and the prompt sits unsubmitted. An unconfirmed send is not delivered: if --wait returns agent_prompt_stalled, the worker never changed state — read the screen and resend.

Plan-first delegation (opt-in)

Plan-first runs only when the user activates it — an explicit ask ("plan first", "plan mode") or a --plan-mode flag on the invocation. The default delegation is direct: launch and run hands-off. Investigation complexity alone does not add a planning approval step.

Once activated, the worker plans, the controller reviews and accepts, then it runs hands-off. The launch flags, shift+tab sequences, status checks, and acceptance menus are exact and differ per TUI. Read references/plan-mode.md in full before launching a plan-first worker.

Delegation packets

Send each worker prompt as a standalone contract. Include:

• repo path and exact objective
• worker role and model
• execution mode: direct (default) or plan-first (user-activated)
• files, packages, or surfaces in scope
• files and behaviors explicitly out of scope
• claimed files or work slice, to avoid conflicts
• dependencies and the current interface/contract the worker can rely on
• expected evidence needed for this claim: changed files, commands with results and checked inputs, relevant artifacts, and remaining uncertainty
• verification ownership: worker checks, controller integration checks, and any final delivery checks owned by the enclosing workflow
• stop conditions: unexpected code shape, repeated command failure, auth/model blocker, or need for out-of-scope edits

Assign coherent outcomes that can proceed independently. If a consumer depends on an unsettled interface, resolve that interface first or keep producer and consumer under one owner. File count alone is not a reason to split work. Tell workers they share the codebase, must preserve others' changes, and must report interface changes before dependent work proceeds. Reuse the same worker for related integration fixes; send the changed contract and remaining work instead of a fresh discovery assignment.

Worktree isolation

When workers must edit overlapping files in parallel, give each an isolated worktree — herdr manages them natively, as its own labeled workspace:

rtk herdr worktree create --workspace "$HERDR_WORKSPACE_ID" \
  --branch <slug> --label "<slug>" --no-focus --json

Create the worker's tab inside that workspace (tab create --workspace <worktree_workspace_id>) so its cwd is the isolated checkout.

Track workers

Orchestrations are long-running — worker slices take minutes to hours, and a worker is never abandoned because a wait expired. Block on herdr's native agent status in check-in intervals of 3–5 minutes (sized to the slice — longer for heavier slices) instead of polling screens:

rtk herdr agent wait fix-loops --until done --timeout 300000     # completion check-in
rtk herdr agent wait fix-loops --until blocked --timeout 300000  # question or menu
rtk herdr pane wait-output <pane_id> --match "<text>" --timeout 300000

Controller reads never mark a tab seen, so an unfocused worker settles as done, not idle — wait on done. --timeout is the check-in interval, never a deadline on the worker. On expiry, read the screen (rtk herdr agent read fix-loops --source recent-unwrapped --lines 120) and re-enter the wait — loop until the worker reaches a terminal state, asks a question, or a stop condition fires. When a reported status looks wrong, debug detection with rtk herdr agent explain <pane_id> --json.

Maintain a compact registry in the existing task notes or handoff: controller identity; worker agent name, tab label, role, model; workspace/tab/pane ids; objective sent and start time; status (starting, planning, plan-review, plan-accepted, running, blocked, reported, verified, retired); claimed files or work slice; worker-reported commands and results; controller verification performed; final disposition (accepted, rejected, superseded, or blocked).

Keep the tab label current as a slice changes, and announce milestones without stealing focus:

rtk herdr tab rename <tab_id> "opus: fix loops (verifying)"
rtk herdr notification show "Workers done" --body "2/2 verified" --sound done

Verify worker output

Treat worker output as untrusted until verified. Monitor and verify without changing focus:

• Read worker tabs read-only (agent read <name> --source recent-unwrapped --lines 200); ask a worker for a concise status summary when output is unclear.
• Re-open cited files locally to verify high-impact findings. For visual output, open the delivered images and their named visual references side by side; file counts, dimensions, and a worker's verdict do not establish visual fit. Check one representative image before expanding an expensive generation batch.
• Inspect command results, exit status, checked inputs, and evidence paths. Reuse trustworthy worker evidence for unchanged inputs; rerun missing, stale, contradictory, or unverifiable checks. The controller runs integration checks the worker did not cover, plus any checks required by project policy. A worker handoff alone does not invalidate evidence or require a second full suite.
• Review the final diff before accepting any worker patch.
• If a worker edits outside its claim, pause integration and decide: accept, request user-approved cleanup, or supersede with controller edits.

When --lines stops revealing more of a completed response, the TUI is on the terminal's alternate screen and those rows are gone. Ask the worker to write its full report as Markdown in a temp directory and reply with the path, then read the file.

Retire workers

A delegation ends with the worker retired — tab closed. Keep a reported worker available while reviewing or integrating its outcome when related follow-ups are expected. Retire it once the disposition is recorded and that work is done:

rtk herdr tab close <tab_id>

Closing the tab ends the TUI session and its scrollback, so record what the registry needs first — report text, cited line refs, command output. Files, diffs, and worktrees survive on disk.

A worker stays open while mid-run, blocked, awaiting planned integration follow-ups, while its screen is evidence for an unresolved failure, or when the user asks to inspect it — record the reason in the registry. The orchestration is complete only when rtk herdr agent list shows none of this controller's workers still running: every worker retired, or its open tab justified in the registry.

Stop conditions

Stop and report instead of improvising when:

• herdr rejects a valid workspace, tab, or pane ref, or rtk herdr status shows no running server.
• a worker TUI rejects the model alias, auth state, working directory, or a startup flag — report the exact blocker, and get user approval before downgrading a model or switching tools.
• authentication blocks the TUI.
• a worker's status stays unknown while output scrolls and agent explain shows no matched rule — detection is broken or the pane is running a headless process.
• a plan-mode status line or acceptance menu cannot be confirmed via agent read or pane wait-output, or a worker's plan stays out of scope after a re-planning round.
• workers need overlapping edits the controller cannot integrate safely.
• a task needs focus-changing herdr verbs the user has not approved.