---
title: Socket API
description: Control a running Herdr server from scripts, tools, and coding agents.
---

Herdr exposes a local socket API for scripts and agents that need to inspect or control a running session.

Most automation should start with the CLI wrappers. Use the raw socket API only when you need direct request/response control or long-lived event subscriptions.

## Choose an integration layer

| Layer | Use it for |
| --- | --- |
| Agent skill | Teaching a coding agent how to use Herdr from inside a pane. |
| CLI wrappers | Shell scripts, simple orchestration, and human debugging. |
| Raw socket API | Custom tools, protocol clients, and event subscribers. |

The layers share the same control surface.

## What you can control

The socket API can:

- create, list, focus, rename, and close workspaces
- create, list, focus, rename, and close tabs
- list, inspect, split, swap, focus, resize, rename, read, close, and send input to panes
- list, inspect, read, send to, rename, focus, start, and attach agents through CLI helpers
- report custom agent state from hooks and plugins
- subscribe to events and wait for output or state changes
- install and uninstall built-in integrations
- stop the server and reload config

## CLI examples

Create a workspace:

```bash
herdr workspace create --cwd ~/project --label api
```

Create a tab:

```bash
herdr tab create --label logs
```

Split a pane and run a command:

```bash
herdr pane split 1-1 --direction right
herdr pane run 1-2 "npm test"
```

Inspect and rearrange panes:

```bash
herdr pane layout --current
herdr pane neighbor --direction right --current
herdr pane resize --direction right --amount 0.1 --current
herdr pane swap --direction right --current
herdr pane zoom --on --current
herdr pane split 1-1 --direction right --ratio 0.333
```

Wait for an agent:

```bash
herdr wait agent-status 1-1 --status done
```

Read pane output:

```bash
herdr pane read 1-2 --source recent --lines 50
```

## Raw methods

Raw socket method names use dot notation:

| Area | Methods |
| --- | --- |
| Server | `ping`, `server.stop`, `server.reload_config`, `server.agent_manifests`, `server.reload_agent_manifests` |
| Notification | `notification.show` |
| Workspace | `workspace.create`, `workspace.list`, `workspace.get`, `workspace.focus`, `workspace.rename`, `workspace.close` |
| Worktree | `worktree.list`, `worktree.create`, `worktree.open`, `worktree.remove` |
| Tab | `tab.create`, `tab.list`, `tab.get`, `tab.focus`, `tab.rename`, `tab.close` |
| Pane | `pane.split`, `pane.swap`, `pane.zoom`, `pane.layout`, `pane.neighbor`, `pane.edges`, `pane.focus_direction`, `pane.resize`, `pane.list`, `pane.get`, `pane.rename`, `pane.send_text`, `pane.send_keys`, `pane.send_input`, `pane.read`, `pane.report_agent`, `pane.report_agent_session`, `pane.report_metadata`, `pane.clear_agent_authority`, `pane.release_agent`, `pane.close`, `pane.wait_for_output` |
| Agent | `agent.list`, `agent.get`, `agent.read`, `agent.explain`, `agent.send`, `agent.rename`, `agent.focus`, `agent.start` |
| Events | `events.subscribe`, `events.wait` |
| Integrations | `integration.install`, `integration.uninstall` |

Some CLI commands are conveniences around these methods. For example, `herdr agent wait` resolves an agent target and then subscribes to pane agent state events.

Pane control methods use public pane ids such as `1-1`. Omit `pane_id` to use
the server's active focused pane.

```json
{"id":"req_layout","method":"pane.layout","params":{"pane_id":"1-1"}}
{"id":"req_neighbor","method":"pane.neighbor","params":{"pane_id":"1-1","direction":"right"}}
{"id":"req_edges","method":"pane.edges","params":{"pane_id":"1-1"}}
{"id":"req_focus","method":"pane.focus_direction","params":{"direction":"right"}}
{"id":"req_resize","method":"pane.resize","params":{"pane_id":"1-1","direction":"right","amount":0.1}}
{"id":"req_zoom","method":"pane.zoom","params":{"pane_id":"1-1","mode":"toggle"}}
{"id":"req_split","method":"pane.split","params":{"direction":"right","ratio":0.333}}
```

`pane.layout` returns the tab layout snapshot with `workspace_id`, `tab_id`,
`zoomed`, outer `area`, `focused_pane_id`, pane rects, and split rects/ratios.
`pane.neighbor` and `pane.edges` include that same layout snapshot so clients
can make the next decision without private layout state.

`pane.swap` supports directional and explicit forms:

```json
{"id":"req_swap_dir","method":"pane.swap","params":{"pane_id":"1-1","direction":"right"}}
{"id":"req_swap_explicit","method":"pane.swap","params":{"source_pane_id":"1-1","target_pane_id":"1-2"}}
```

Swap is same-tab only. It preserves split shape, split ratios, pane ids, and
running processes. The response is `type: "pane_swap"` with `changed`, optional
`reason`, `source_pane_id`, optional `target_pane_id`, `focused_pane_id`, and
`layout`. Reason values are `no_neighbor`, `same_pane`, `not_found`, and
`cross_tab`. When a tab is zoomed, swap keeps zoom active and mutates the hidden
full-tab layout.

`pane.zoom` toggles, enables, or disables zoom for the target pane's tab:

```json
{"id":"req_zoom_toggle","method":"pane.zoom","params":{"pane_id":"1-1"}}
{"id":"req_zoom_on","method":"pane.zoom","params":{"pane_id":"1-1","mode":"on"}}
{"id":"req_zoom_off","method":"pane.zoom","params":{"pane_id":"1-1","mode":"off"}}
```

Omitting `pane_id` targets the server's active focused pane. The response is
`type: "pane_zoom"` with `changed`, `zoom_changed`, `focus_changed`, optional
`reason`, `pane_id`, `focused_pane_id`, `zoomed`, and `layout`. `changed` is
true when either zoom state or focus changed. Reason values are `single_pane`,
`already_zoomed`, and `already_unzoomed`.

The CLI wrapper for `notification.show` is:

```bash
herdr notification show "build failed" --body "api workspace" --position top-left --sound request
```

Show a user notification through the configured toast delivery:

```json
{"id":"req_notify","method":"notification.show","params":{"title":"build failed","body":"api workspace","position":"top-left","sound":"request"}}
```

`title` is required and must contain visible text after control characters and repeated whitespace are removed. `body` is optional. Herdr collapses newlines, tabs, carriage returns, and repeated whitespace into spaces, then trims notification text to 80 characters for `title` and 240 characters for `body`. An empty sanitized `title` returns `invalid_params`. `position` is optional and applies only when `ui.toast.delivery = "herdr"`; desktop positions are relative to the full Herdr frame, and omitted positions use `ui.toast.herdr.position`. Terminal, system, and off delivery ignore `position`. `sound` is optional and can be `none`, `done`, or `request`; it defaults to `none` and plays only when the notification is shown.

The response reports whether anything was shown:

```json
{"id":"req_notify","result":{"type":"notification_show","shown":true,"reason":"shown"}}
```

Possible reasons are `shown`, `disabled`, `rate_limited`, `no_foreground_client`, and `busy`. `disabled` means `ui.toast.delivery = "off"`. `busy` means an existing in-app toast was not replaced. Terminal and system delivery are best-effort through the current foreground attached Herdr client.

Worktree methods manage Git checkouts as Herdr workspaces. `worktree.create` creates a checkout and returns the new `workspace`, `tab`, `root_pane`, and `worktree` records. `worktree.open` opens an existing checkout or returns the already-open workspace. `worktree.remove` runs `git worktree remove` against a linked child workspace and never deletes the branch.

Create a worktree from a source workspace:

```json
{"id":"req_1","method":"worktree.create","params":{"workspace_id":"1","branch":"worktree/api","focus":false}}
```

Open an existing checkout:

```json
{"id":"req_2","method":"worktree.open","params":{"workspace_id":"1","branch":"worktree/api","focus":true}}
```

Remove a linked checkout:

```json
{"id":"req_3","method":"worktree.remove","params":{"workspace_id":"2","force":false}}
```

Use at most one of `workspace_id` or `cwd` for `worktree.list`, `worktree.create`, and `worktree.open`; omit both to use the active workspace. Use exactly one of `path` or `branch` for `worktree.open`. Raw socket `cwd` and `path` values must be absolute; the CLI expands relative `--cwd` and `--path` values before sending requests. Workspace responses include optional `worktree` provenance when a workspace belongs to a Herdr worktree group. Worktree commands can emit `workspace.updated` when an existing workspace gains or changes worktree provenance.

## Socket transport

Herdr uses newline-delimited JSON over a Unix domain socket.

Send one request per line:

```json
{"id":"req_1","method":"ping","params":{}}
```

A successful response includes the same `id`:

```json
{"id":"req_1","result":{"type":"pong"}}
```

Event subscriptions keep the connection open after the initial response.

## Socket paths

The default socket lives under your Herdr config directory.

Named sessions have separate sockets:

```text
~/.config/herdr/herdr.sock
~/.config/herdr/sessions/<name>/herdr.sock
```

Resolution order:

1. explicit CLI `--session <name>`
2. `HERDR_SOCKET_PATH`
3. `HERDR_SESSION=<name>`
4. default session socket

Use `HERDR_SOCKET_PATH` only for low-level overrides.

## Agent state reporting

Integrations report agent state with `pane.report_agent`.

```json
{
  "id": "req_1",
  "method": "pane.report_agent",
  "params": {
    "pane_id": "1-1",
    "source": "custom:docs",
    "agent": "docs-bot",
    "state": "working",
    "message": "building docs",
    "custom_status": "indexing"
  }
}
```

`state` is semantic. It affects waits, notifications, and rollups.

`custom_status` is visual. It can show a short label like `indexing` without changing semantic behavior.

Session-only official integrations report native session references with `pane.report_agent_session`. State-reporting integrations can still include native session references in `pane.report_agent`. State-independent session reports do not affect waits, notifications, or rollups.

```json
{
  "id": "req_2",
  "method": "pane.report_agent_session",
  "params": {
    "pane_id": "1-1",
    "source": "herdr:codex",
    "agent": "codex",
    "agent_session_id": "..."
  }
}
```

`pane.get`, `pane.list`, `agent.get`, and `agent.list` expose a read-only `agent_session` object when Herdr has a stored native session reference:

```json
{
  "agent_session": {
    "source": "herdr:codex",
    "agent": "codex",
    "kind": "id",
    "value": "..."
  }
}
```

If no native session reference is stored, the field is omitted.

`pane.get`, `pane.list`, `agent.get`, and `agent.list` also expose `foreground_cwd` when Herdr can resolve the cwd of the process currently controlling the pane PTY. The existing `cwd` field remains the pane/workspace cwd used for labels, follow-cwd behavior, and restored session state.

Use `pane.report_metadata` when a user hook wants to customize presentation without taking over lifecycle state from a Herdr integration.

```json
{
  "id": "req_2",
  "method": "pane.report_metadata",
  "params": {
    "pane_id": "1-1",
    "source": "user:claude-title",
    "agent": "claude",
    "title": "Refactor auth middleware",
    "display_agent": "Claude: auth",
    "custom_status": "refactor auth",
    "state_labels": {
      "working": "refactoring auth",
      "idle": "ready",
      "done": "review ready"
    },
    "ttl_ms": 3600000
  }
}
```

Metadata reports are display-only. Valid metadata can override the pane title, displayed agent name, compact custom status, and visible state labels. `working`, `blocked`, `idle`, waits, notifications, and rollups still come from semantic state. Native session restore comes from stored official session references. `agent` is an optional guard for the authoritative agent label; `applies_to_source` is an optional guard for the active lifecycle authority source. Use `display_agent` to change the visible name. `state_labels` keys must be `idle`, `working`, `blocked`, `done`, or `unknown`. Use clear fields such as `clear_custom_status: true` with the same `source` to remove one presentation override.

## Event subscriptions

Subscribe to events when you need a long-lived stream:

```json
{
  "id": "sub_1",
  "method": "events.subscribe",
  "params": {
    "subscriptions": [
      { "type": "pane.agent_status_changed", "pane_id": "1-1", "agent_status": "blocked" }
    ]
  }
}
```

The first response acknowledges the subscription. Later lines are pushed events.

Workspace event subscriptions include `workspace.created`, `workspace.updated`, `workspace.renamed`, `workspace.closed`, and `workspace.focused`.

Use `events.wait` when you want one matching event and then a response.

## Reading panes

Use `pane.read` through the CLI unless you are writing a protocol client.

```bash
herdr pane read 1-1 --source visible --lines 80
herdr pane read 1-1 --source recent --lines 120
herdr pane read 1-1 --source recent-unwrapped --lines 120
herdr pane read 1-1 --source detection
```

`recent-unwrapped` is useful for logs because it ignores soft wrapping.
`detection` returns the bottom-buffer snapshot used by agent screen detection.

## Waiting for state

Use waits to coordinate agents and scripts.

```bash
herdr wait agent-status 1-1 --status done
herdr wait agent-status 1-1 --status blocked
```

Agent waits observe semantic state, not arbitrary command completion.

## Response shapes

Successful responses look like this:

```json
{
  "id": "req_1",
  "result": {
    "type": "pane_info",
    "pane": {
      "pane_id": "1-1",
      "terminal_id": "term_abc123",
      "workspace_id": "1",
      "tab_id": "1-1",
      "focused": true,
      "agent_status": "working",
      "revision": 42
    }
  }
}
```

`server.agent_manifests` returns the active agent detection manifest sources and remote update diagnostics without reloading rules:

```json
{
  "id": "req_1",
  "result": {
    "type": "agent_manifest_status",
    "last_check_unix": 1781043522,
    "last_result": "checked",
    "manifests": [
      {
        "agent": "cursor",
        "source": "/home/me/.config/herdr/agent-detection/cursor.toml",
        "source_kind": "local override",
        "active_version": "2026.06.10.1",
        "cached_remote_version": "2026.06.10.1",
        "local_override_shadowing_remote": true,
        "remote_update_result": "current"
      }
    ]
  }
}
```

Fields such as `last_check_unix`, `last_result`, `active_version`, `cached_remote_version`, `remote_update_result`, `remote_update_error`, `remote_last_checked_unix`, and `warning` are omitted when not available. `server.reload_agent_manifests` returns `agent_manifest_reload` with the same `manifests` item shape after reloading the in-memory rule cache.

`agent.explain` evaluates the target pane's detection snapshot in the running server using the server's active manifest cache:

```json
{
  "id": "req_2",
  "method": "agent.explain",
  "params": { "target": "1-1" }
}
```

The response contains the same explain object printed by `herdr agent explain --json`, including the final state, manifest source and version, matched rule, evaluated rule evidence, skip-state reason, idle fallback reason, and `screen_detection_skip_reason` when a full lifecycle hook authority makes screen rules non-authoritative.

Clients need a running server that supports `agent.explain`; after upgrading Herdr, restart or live-handoff the server before relying on this method.

Errors look like this:

```json
{
  "id": "req_1",
  "error": {
    "code": "not_found",
    "message": "pane not found"
  }
}
```

## Protocol stability

Herdr has a protocol version for client/server compatibility. Protocol changes are reviewed with release compatibility in mind.

Check the server protocol with `ping` or `herdr status` before depending on new behavior. Handle unknown fields gracefully.
