Lark Events
Prerequisite: Read ../lark-shared/SKILL.md first for authentication, --as user/bot switching, Permission denied handling, and safety rules.
Core commands
| Command | Purpose |
|---|
lark-cli event list [--json] | List all subscribable EventKeys |
lark-cli event schema <EventKey> [--json] | Show an EventKey's params and output schema |
lark-cli event consume <EventKey> [flags] | Blocking consume; events → stdout NDJSON |
lark-cli event status [--json] [--fail-on-orphan] | Inspect the local bus daemon status |
lark-cli event stop [--all] [--force] | Stop the bus daemon |
Common flags
| Flag | Description |
|---|
--param key=value / -p | Business params (repeatable; comma-separated for multi-value). Unknown keys fail with valid names listed inline |
--jq <expr> | jq expression to filter / transform each event; empty output skips the event |
--max-events N | Exit after N events. Default 0 = unlimited |
--timeout D | Exit after duration D (e.g. 30s, 2m). Default 0 = no timeout. Whichever of --max-events / --timeout fires first wins |
--output-dir <dir> | Write each event as a file (relative paths only; prevents traversal) |
--quiet | Suppress stderr diagnostics. AI should not use this — it silences the ready marker |
--as user|bot|auto | Identity for the session (see lark-shared) |
Examples
# Default: stream every event for the key (no filter, no projection)
lark-cli event consume im.message.receive_v1 --as bot
# Grab one sample event to inspect payload shape
lark-cli event consume im.message.receive_v1 --max-events 1 --timeout 30s --as bot
# Run for 10 minutes then auto-exit
lark-cli event consume im.message.receive_v1 --timeout 10m --as bot
# Consume multiple EventKeys concurrently (one shape per process, no dispatcher)
lark-cli event consume im.message.receive_v1 --as bot > receive.ndjson &
lark-cli event consume im.message.reaction.created_v1 --as bot > reaction.ndjson &
wait
Call flow
lark-cli event list --json → pick a legal keylark-cli event schema <key> --json → read resolved_output_schema + jq_root_path to determine field pathslark-cli event consume <key> [--jq '<expr>'] → consume
Subprocess contract
Ready marker
event consume's stderr emits a fixed line [event] ready event_key=<key>. Parent processes should block on stderr until this line appears, then start reading stdout. Do not fall back to sleep.
stdin EOF = graceful exit
event consume treats stdin close as a shutdown signal (wired for AI subprocess callers). < /dev/null / nohup / systemd's default StandardInput=null will cause an immediate graceful exit (stderr reason: signal). To keep running:
- Feed stdin a source that never EOFs:
< <(tail -f /dev/null)
- Or run bounded:
--max-events N / --timeout D
Exit codes & reason
On exit, the last stderr line is [event] exited — received N event(s) in Xs (reason: ...).
| exit code | reason | Trigger |
|---|
| 0 | reason: limit | --max-events reached |
| 0 | reason: timeout | --timeout reached |
| 0 | reason: signal | Ctrl+C / SIGTERM / stdin EOF |
| non-0 | Error: ... (no exited line) | Startup / runtime failure (permissions, network, params, config) |
Orchestrators should treat reason: limit/timeout/signal (all exit 0) as "business completion" and non-zero as "failure".
Never kill -9
Avoid kill -9 on consume processes: for EventKeys with a PreConsume hook (those that register server-side subscriptions via OAPI), kill -9 skips the OAPI unsubscribe and leaks server-side subscriptions (symptoms: "subscription already exists" on restart, duplicate event delivery). Prefer SIGTERM or closing stdin.
One consume, one EventKey (multi-key = multi-shell)
The command takes exactly one positional argument; k1,k2 and wildcards are unsupported. Listening to N keys means N subprocesses — this is intentional:
- One shape per process stdout; no dispatcher logic required in the AI
- Fault isolation (one key failing doesn't affect others)
- Independent
--as / --jq / --max-events / --timeout per key
All N consumers share a single bus daemon (UDS local IPC), so the overhead is small
Writing jq via schema
event schema <key> --json is the source of truth for writing --jq. Four things to look at:
(1) Where fields start — see jq_root_path
- Value
"." → fields are at the top level, write .chat_id
- Value
".event" → fields are inside a V2 envelope, write .event.chat_id
(2) Field list and types — see resolved_output_schema.properties.<name>
Each field carries type / description, and some also have format. Snippet (from event schema im.message.receive_v1 --json):
{
"chat_id": {"type":"string", "format":"chat_id", "description":"Chat ID, prefixed with oc_"},
"sender_id": {"type":"string", "format":"open_id", "description":"Sender open_id, prefixed with ou_"},
"create_time": {"type":"string", "format":"timestamp_ms", "description":"Send time as ms-epoch string"}
}
(3) Field semantics — see the format tag
Lark-defined semantic tags (not JSON Schema's standard format). Common values: open_id / chat_id / message_id / timestamp_ms / email. Purpose: distinguish "same string type, different meanings" fields so you can reverse-lookup via API or convert formats.
(4) Decoded state — read the field's description
event consume runs Process hooks that may pre-decode some payload fields (flattening V2 envelopes, rendering .content to plain text, etc.) — behavior differs from raw OAPI. Always read the field's description before writing jq, especially for generic field names like content / data / body / payload.
Why it matters: blindly applying fromjson to an already-decoded text field makes jq error on every event and silently drop it — the consumer looks alive but emits nothing, with only a single WARN line buried on stderr. (This is the general behavior: any jq runtime error skips the event with a one-line WARN; the loop does not abort.)
Don't shortcut the schema: when projecting event schema --json with jq, do not strip .description from properties — that's the field that tells you whether a field is already decoded. Dump the full property objects, not just keys.
Aside: --param's valid parameters also live in the schema — the params section lists name / type / required / enum / default / description; section missing = this key accepts no --param.
Topic index
| Topic | Reference | Coverage |
|---|
| IM | references/lark-event-im.md | Catalog of 11 IM EventKeys + shape notes (flat vs V2 envelope) + im.message.receive_v1 field gotchas (sender_id is open_id only; .content is plain text except for interactive cards) + common jq recipes (filter by chat_type / message_type / sender) |