Reject malformed tasks=[...] batches before any child agent is spawned:
- exact-duplicate goals (case/whitespace-normalized), error names both
task indices
- placeholder goals: bare 'TODO', bare 'task N', unexpanded <...> or
{...} template markers, or goals shorter than 10 chars after strip
- 1-task batches, with an error pointing the model at the single
`goal` form instead
All checks are batch-only — the single-goal form is exempt by design
(short goals like goal="test" are valid there). Error strings are
actionable: each tells the model exactly how to fix the call.
Tool schema is unchanged (byte-stable); validation is runtime-only in
the existing batch-validation region.
Existing tests using terse batch goals ("A"/"B"/"C") updated to
realistic distinct goals per the new contract.
Inspired by: MoonshotAI/kimi-code agent-swarm.md validation rules (MIT)
Users can declare shell scripts in config.yaml under a hooks: block that
fire on plugin-hook events (pre_tool_call, post_tool_call, pre_llm_call,
subagent_stop, etc). Scripts receive JSON on stdin, can return JSON on
stdout to block tool calls or inject context pre-LLM.
Key design:
- Registers closures on existing PluginManager._hooks dict — zero changes
to invoke_hook() call sites
- subprocess.run(shell=False) via shlex.split — no shell injection
- First-use consent per (event, command) pair, persisted to allowlist JSON
- Bypass via --accept-hooks, HERMES_ACCEPT_HOOKS=1, or hooks_auto_accept
- hermes hooks list/test/revoke/doctor CLI subcommands
- Adds subagent_stop hook event fired after delegate_task children exit
- Claude Code compatible response shapes accepted
Cherry-picked from PR #13143 by @pefontana.
Teknium
embwl0x
Peter Fontana