nanny run

Spawns a child process under full Nanny enforcement. Reads nanny.toml from the current directory and kills the process the moment any limit is crossed.

nanny run [OPTIONS] [-- ARGS...]

Examples

# Run with base [limits] (reads [start].cmd from nanny.toml)
nanny run

# Run with a named limit set
nanny run --limits=researcher

Options

Flag	Type	Default	Description
`--limits=<name>`	string	—	Activate a named limit set from `nanny.toml`. Inherits from `[limits]`.
`--config=<path>`	path	`./nanny.toml`	Path to config file.

Exit codes

Code	Meaning
`0`	Process exited cleanly (`AgentCompleted`)
`1`	Nanny stopped the process, a spawn failure occurred, or an internal error occurred

Stderr

When Nanny stops a process it prints the reason to stderr:

nanny: stopped — TimeoutExpired
nanny: stopped — BudgetExhausted
nanny: stopped — MaxStepsReached
nanny: stopped — ToolDenied
nanny: stopped — RuleDenied

This message is separate from the structured event log, which goes to stdout (or a configured file).

Event log

Every run emits NDJSON events to stdout. ExecutionStarted is always first; ExecutionStopped is always last:

{"event":"ExecutionStarted","ts":1711234567000,"limits":{"steps":100,"tokens":1000,"timeout":30000},"limits_set":"[limits]","command":"python agent.py"}
{"event":"ToolAllowed","ts":1711234567120,"tool":"http_get"}
{"event":"StepCompleted","ts":1711234567800,"step":1}
{"event":"ExecutionStopped","ts":1711234572000,"reason":"BudgetExhausted","steps":12,"tokens_spent":1000,"elapsed_ms":5000}

Pipe to a file to keep your agent’s own output separate:

nanny run > nanny.log

For per-function governance (marking individual tools and rules in code), see the Rust SDK guide or Python SDK guide.

Concepts

SDKs

Guides

CLI

Reference

Examples

Options

Exit codes

Stderr

Event log

​Examples

​Options

​Exit codes

​Stderr

​Event log

Examples

Options

Exit codes

Stderr

Event log