Subagent Spawn Command Builder

Build sessions_spawn command payloads from JSON profiles. Use when you want reusable subagent profiles (model/thinking/timeout/cleanup/agentId/label) and command-ready JSON without executing spawn.

Generate sessions_spawn payload JSON from profile config. This skill does not execute sessions_spawn; it only builds payload/command JSON.

Files

• Builder script: scripts/build_spawn_payload.mjs
• Builder log: state/build-log.jsonl

Supported sessions_spawn parameters

• task (required)
• label (optional)
• agentId (optional)
• model (optional)
• thinking (optional)
• runTimeoutSeconds (optional)
• cleanup (keep|delete, optional)
• cwd (optional) — working directory for the subagent
• mode (run|session, optional)

Setup

Read the "Subagent Spawn Profiles" table in TOOLS.md for default values per profile. Pass values as explicit CLI arguments (--model, --thinking, --run-timeout-seconds, --cleanup). The --profile flag is now a logging label, not a lookup key for a config file.

Generate payload

bash

skills/subagent-spawn-command-builder/scripts/build_spawn_payload.mjs \
  --profile heartbeat \
  --task "Analyze recent context and return a compact summary" \
  --label heartbeat-test \
  --model claude-sonnet-4-20250514 \
  --thinking low \
  --run-timeout-seconds 300 \
  --cleanup delete

The script prints JSON directly usable for sessions_spawn.

Merge/priority rule

All values come from explicit CLI arguments. --profile is a logging label only (not a config lookup key). Refer to the "Subagent Spawn Profiles" table in TOOLS.md for recommended defaults per profile.

task always comes from CLI --task.

CLI options

Note: this builder is Node.js (.mjs) based. If generated tasks include Python execution steps, write commands with python3 (not python).

• --profile (required)
• --task (required)
• --label
• --agent-id
• --model
• --thinking
• --run-timeout-seconds
• --cleanup keep|delete
• --cwd <path>
• --mode run|session