numbat

Endpoint visibility into AI agent activity, with local detection, optional pre-action blocking, and forensic reconstruction.

numbat observes supported desktop, CLI, IDE, and gateway agents through local hooks and plugins, OTLP/HTTP logs, and on-disk session artifacts. Live and at-rest activity is normalized into one event model and evaluated by the same CEL rule engine. Detection runs locally; records can be written to stdout or a local file and optionally delivered over HTTP.

The coverage matrix is authoritative for each host and surface. Blocking is off by default and limited to supported synchronous pre-action hooks; see the enforcement guide.

Features

• Live monitoring through hooks, plugins, and OTLP/HTTP log exporters.
• Endpoint-local detection with built-in CEL rules, multi-step sequence rules, and custom YAML rules.
• Opt-in blocking through supported pre-action hooks. Enforce mode is disabled by default and applies only to rules marked enforce: true; all shipped rules are monitor-only.
• Forensic reconstruction from supported on-disk session artifacts, without prior numbat instrumentation.
• Versioned NDJSON records for events, findings, enforcement decisions, indicators, and scan summaries. Events and findings retain source references; JSON Schemas define the wire format.
• Read-only artifact scanning with secret redaction. Normal record output never includes a complete raw transcript; adding raw evidence files to a case bundle is opt-in.
• Inventory and investigation tools for read-only agent discovery, per-session timelines, and portable case bundles with SHA-256 manifests.
• Single-binary distribution for macOS, Linux, and Windows, built without cgo.

Quick start

Install

Download a release for macOS, Linux, or Windows on amd64 or arm64. Each release includes SHA-256 checksums. You can also install with Go 1.26.6 or newer:

go install github.com/perplexityai/numbat/cmd/numbat@latest

CGO_ENABLED=0 go build -trimpath -o numbat ./cmd/numbat

$env:CGO_ENABLED = "0"
go build -trimpath -o numbat.exe ./cmd/numbat

Inventory and scan

These read-only commands do not install hooks or change agent configuration:

numbat agents
# scan all discovered parser-backed agents
numbat scan
# or limit automatic discovery to Codex
numbat scan --agent codex

Monitor and enforce

Install live monitoring for any agent with live-capture support; the commands below use Codex as a concrete example. Hooks start in monitor-only mode. --emit all writes events, findings, indicators, and applicable enforcement decisions to ~/.numbat/records.ndjson.

numbat hook install --agent codex --emit all
numbat hook status --agent codex

Hook trust: Requirements vary by agent and scope. For the Codex user hook above, review and trust its current definition in /hooks (CLI) or Settings > Hooks (app), including after changes such as --enforce. Codex hooks installed with --managed are trusted by policy. hook status verifies configuration, not execution or delivery. See the deployment guide for other agents and scopes.

All shipped rules are monitor-only. To enforce a detection, copy its complete shipped YAML into a controlled operator directory, keep the same id, add enforce: true, and bump its version. Validate and install that effective policy for a supported pre-action hook:

numbat rules check --rules-dir ./numbat-policy
numbat hook install --agent codex --emit all \
  --rules-dir ./numbat-policy --enforce

Example output