Agents

Herdr is built for running more than one coding agent at a time. Each agent stays in a real terminal pane with its shell, logs, prompts, and running processes intact. Herdr tracks which panes contain agents, rolls their state up to tabs and workspaces, and lets you jump straight to the pane that needs attention instead of polling every terminal by hand.

To coordinate agents from scripts or from another agent, see Agent automation.

Supported agents

Automatic detection works out of the box for common coding agents. The table shows which signal determines idle, working, and blocked for each one.

Detected but less thoroughly tested: Gemini CLI and Cline. Unsupported agents still run normally as terminal processes. They just may not get rich state unless you add an integration or report state over the socket API.

Status authority

Herdr first detects the foreground process in each pane. After that, each pane has one status authority.

For agents with complete lifecycle hooks, the integration is authoritative when it is installed and actively reporting for the running pane. Herdr uses those hook reports for idle, working, blocked, and session identity. It does not also run screen manifest fallback for that same lifecycle authority. This avoids two competing sources of truth.

For agents without complete lifecycle hooks, Herdr identifies the foreground process and reads the live bottom-buffer screen snapshot. It evaluates TOML manifests against that snapshot to classify idle, working, and blocked. For agents that emit them, manifests can also match terminal title and progress (OSC) sequences as detection evidence; when that evidence is absent, screen rules carry detection on their own.

The screen snapshot comes from the recent bottom of the pane buffer, not the scrolled viewport. If you scroll back in Herdr, detection still follows the live agent UI at the bottom.

Integrations marked session in the table above are intentionally not lifecycle authorities. They provide native session identity for restore, but their hooks do not cover the whole lifecycle. They can miss permission approval results, escape interrupts, or other transitions. For those agents, Herdr still uses screen manifest detection.

VMs and sandbox wrappers

On Linux and macOS, a host-visible wrapper can hide the real agent process from Herdr. Set HERDR_AGENT=<agent> on the wrapper command to tell Herdr which existing agent screen manifest to use. For example, run HERDR_AGENT=claude fence -- claude on Linux or HERDR_AGENT=claude nono run --profile claude-code -- claude on macOS. The hint applies only to that foreground process. Herdr cannot see it if you set it only inside a VM or container. Avoid exporting it globally unless every inherited foreground process should be treated as that agent.

Some restricted Linux runtimes do not expose a terminal foreground process group. Start the Herdr server with HERDR_PROCESS_DETECTION=child-groups to opt into direct child-process-group inference when native detection is unavailable. Native detection remains preferred, and the default native mode never performs this inference. The opt-in mode is best effort: a newer background job can be mistaken for the foreground job. The variable is read by the server and requires a restart; set it in the remote server environment rather than on an attaching client.

Blocked state

Blocked detection is deliberately strict for screen-manifest agents. Herdr only marks blocked when the live bottom-buffer snapshot matches known visible approval, question, or permission UI. If no manifest rule matches for a known agent, Herdr falls back to idle and labels that fallback as default_known_agent_idle_fallback in explain output.

This means unusual new agent prompts may initially show as idle instead of blocked until Herdr learns that screen shape. The misclassification affects only the visible status and waits. It should not make Herdr send input or take destructive action.

Detection manifests

Bundled manifests live inside Herdr. Herdr also checks herdr.dev for remote manifest updates and applies valid per-agent rule updates automatically without requiring a Herdr restart. Remote manifests are stored in Herdr’s state directory. Set [update] manifest_check = false to disable background remote manifest checks.

Local overrides can replace a remote or bundled manifest from the platform config directory:

~/.config/herdr/agent-detection/<agent>.toml

Local overrides always win. Without a local override, Herdr uses the newer compatible manifest between the cached remote manifest and the bundled manifest in the running binary. On debug builds, the same config helper may use a development directory such as herdr-dev. Invalid override files are ignored with a warning and Herdr falls back to the cached remote or bundled manifest for that agent.

Remote manifests patch detection rules for agents Herdr already knows how to identify. Adding a completely new agent still requires a Herdr binary update for process detection, labels, and integration behavior.

The running server loads active manifests into memory on startup. Automatic remote manifest updates reload that in-memory cache after new rules are written. Run herdr server update-agent-manifests to fetch remote manifest updates immediately and reload the running server. After editing a local override manually, restart Herdr or run herdr server reload-agent-manifests to apply the file to the running server.

Use herdr agent explain when a pane shows the wrong state:

herdr agent explain <target>herdr agent explain --file screen.txt --agent codex --json

Terminal window

Live explain is evaluated by the running server, so it reflects the active manifest cache. The explain output shows the agent, final state, whether screen detection was skipped by a full lifecycle authority, manifest source and version, cached remote version, local override shadowing, remote update status, matched rule, visible evidence flags, matcher and region evidence for evaluated rules, skipped-update reason for transcript viewers, and the idle fallback reason when no rule matched.

Herdr can run inside tmux as the outer terminal environment. Agent detection does not inspect tmux sessions launched inside a Herdr pane. If a shell framework auto-enters tmux inside Herdr, Herdr sees tmux as the pane process instead of the agent behind it.

State rollups

The sidebar rolls state upward.

A blocked agent makes its pane, tab, and workspace look blocked. A working agent makes the workspace look active. A done agent stays visible until you view it.

This is the main Herdr workflow: start several agents, let them work in parallel, and use the sidebar to see which project needs a decision, which one is still running, and which one is ready to review.

Direct integrations

Install the integration for each agent you use to give Herdr hook or plugin reports instead of screen detection alone:

herdr integration install claudeherdr integration status

Terminal window

Each supported agent has its own integration name and behavior. See Integrations for the per-agent details and the full install list. If you are building an agent, the custom integration guide shows how to report lifecycle state without adding native support to Herdr.

Custom agent labels

You can rename an agent target for display:

herdr agent rename w1:p1 reviewerherdr agent rename reviewer --clear

Terminal window

Targets accept a unique live agent name or the pane ID that currently hosts the agent. Terminal IDs and bare agent-kind labels are not accepted.

Custom status labels

Integrations report lifecycle state as semantic state only. Add display customization separately with pane metadata tokens.

herdr pane report-agent w1:p1 \  --source custom:indexer \  --agent docs-bot \  --state working
herdr pane report-metadata w1:p1 \  --source custom:indexer-display \  --token summary=indexing

Terminal window

state controls waits, notifications, and rollups. The summary token is display-only and can be used as $summary in an Agent sidebar row.

Agent sidebar rows can also opt into terminal_title or terminal_title_stripped; neither appears in the default rows. The first shows the latest safety-normalized OSC 0/2 terminal title. The second removes one recognized leading activity or spinner glyph and following whitespace. Herdr owns these values on the server; they are ephemeral across a cold restart and remain independent of metadata titles and semantic agent state. Spinner animation can therefore update the raw title without producing a pane update when the stripped text stays the same.

Attach directly to an agent

Attach your current terminal to one agent terminal instead of the full Herdr UI:

herdr agent attach reviewer

Terminal window

Detach with ctrl+b q. Send a literal ctrl+b with ctrl+b ctrl+b.

Scroll with the mouse wheel or plain page up/page down. Normal input jumps back to the bottom.

Use --takeover if another direct attach client already owns input:

herdr agent attach reviewer --takeover

Terminal window

Use herdr terminal attach <terminal_id> when you want the same direct attach behavior for a non-agent terminal.

Last updated Oct 08, 2026