ak activity tail

Follow only newly appended local activity events and consume the JSON stream as NDJSON.

Use ak activity tail while another process produces AgentKit activity. It starts at the current end of the log, so it does not replay existing history.

Usage

ak activity tail

The command accepts no positional arguments and has no command-specific flags.

Stream behavior

ak activity tail
ak activity tail --json

The command polls the local log for appended complete lines. A missing log is not an error; the process waits for it to appear. Empty and malformed lines are skipped.

The stream is best-effort. Events can be dropped when the internal bounded buffer is backpressured, and transient open/read errors are retried rather than reported. Use ak activity list --since <last-id> after reconnecting when you need to fill a gap.

Human and JSON output

Human mode writes one line per event with id, kind, skill, and timestamp. It prints no initial header or historical snapshot.

--json emits newline-delimited JSON, not one finite document. Every line is a separate envelope:

schema_version: 1
kind: activity.event
data.id, data.ts, data.kind
data.skill, data.runtime, data.duration_ms, data.exit_code: optional

Keep stdout open and decode one JSON object per line. Do not wait for a closing array.

TTY, stdin, and cancellation

Tail behavior is the same on a TTY and in a pipe. It never prompts and does not read stdin. --yes and --no-interactive do not change the stream.

The implementation writes events directly rather than through the normal quiet renderer, so --quiet does not suppress streamed event lines. Stop with Ctrl-C, SIGTERM, or context cancellation; the normal signal-aware cancellation path exits 0 and prints no terminal JSON record.

Local effects and privacy

The command only reads ~/.agentkit/activity/events.ndjson; AGENTKIT_HOME changes the base. It does not create, truncate, rotate, or prune the log, and it does not contact a network service or provider.

Events expose bounded run metadata, not prompts or skill arguments. Protect the stream as local operational data because skill names, runtime names, durations, and exit codes can still reveal work patterns.

Exit behavior

Exit	Meaning
`0`	The stream ended through normal cancellation or its worker ended cleanly.
`1`	Home resolution or stdout encoding/writing failed, or a positional argument was supplied.
`2`	A flag was invalid.

Runtime failures in --json mode can have no error envelope. A clean cancellation also has no final envelope, so process status distinguishes the two.

On macOS, the CLI-wide first-launch guard can also write ~/.agentkit/.first-run-darwin and print a one-time hint to stderr before this command runs.