Minion Orchestrator

Minion Orchestrator

Contract

Minions is a Postgres-native job queue for durable, observable background work. This single skill handles two lanes:

• Deterministic shell jobs (gbrain jobs submit shell ...)
• LLM subagent jobs (gbrain agent run ...)

When to route to Minions: durable, observable work that must survive restarts, fan out across many parallel tasks, or persist across sessions. Routing policy is defined in skills/conventions/subagent-routing.md — the project default is pain_triggered (native subagents first, Minions after specific pain signals fire); Mode A (all-through-Minions) is opt-in.

Guarantees:

• Jobs survive gateway restart (Postgres-backed)
• Every job has structured progress, token accounting, and session transcripts
• Running agents can be steered mid-flight via inbox messages
• Jobs can be paused, resumed, or cancelled at any time
• Parent-child DAGs with configurable failure policies

Route the Request: Shell Job vs Subagent

If intent is ambiguous, ask one clarification: "Do you want a deterministic shell command job, or an LLM agent job?"

Shell Jobs (Deterministic Scripts)

Use for reproducible command execution, ETL steps, cron work, and scriptable tasks where no LLM reasoning loop is needed.

Preconditions (read before submitting your first shell job)

• GBRAIN_ALLOW_SHELL_JOBS=1 must be set on the worker environment. Without it, the shell handler refuses to register and submissions sit in waiting silently. Gate lives in src/core/minions/handlers/shell.ts.
• Security: flipping GBRAIN_ALLOW_SHELL_JOBS=1 authorizes arbitrary command execution on the worker. On a shared queue, this is a remote code execution surface. Treat as privileged infrastructure authorization.
• Execution mode — pick one:
  • Postgres + daemon: gbrain jobs work runs a persistent worker that claims and executes jobs from the queue.
  • PGLite + --follow: gbrain jobs submit ... --follow runs inline. The daemon mode is not available on PGLite (exclusive file lock). See docs/guides/minions-shell-jobs.md.
• MCP boundary: shell-job submission is CLI-only. submit_job name="shell" over MCP throws an OperationError with code permission_denied ("'shell' jobs cannot be submitted over MCP") because shell is in PROTECTED_JOB_NAMES. Agents CAN observe shell jobs via get_job / list_jobs / get_job_progress (not protected), but cannot submit them. Operator or autopilot submits; agent observes.
• Verify setup: after configuration, run gbrain jobs stats (CLI) to confirm the worker is registered and consuming the queue.

Submit (CLI, operator or autopilot)

Shell jobs take their command via --params as a JSON object with cmd (string) or argv (array), plus cwd and optional env.

Command string form:

gbrain jobs submit shell --params '{"cmd":"echo hello","cwd":"/abs/path"}'

Argv form (no shell expansion):

gbrain jobs submit shell --params '{"argv":["bash","-lc","echo hello"],"cwd":"/abs/path"}'

Inline execution on PGLite or any one-shot deployment:

gbrain jobs submit shell --params '{"cmd":"echo hello","cwd":"/tmp"}' --follow

Queue/lifecycle flags exposed by gbrain jobs submit --help: --queue, --priority, --delay, --max-attempts, --max-stalled, --backoff-type, --backoff-delay, --backoff-jitter, --timeout-ms, --idempotency-key, --dry-run.

Monitor (agents or operator)

These operations are MCP-callable and safe for agent use:

list_jobs --name shell --status active
get_job ID
get_job_progress ID

Check structured result fields (exit code, stdout/stderr tails, attempts, timings) from get_job. Use gbrain jobs stats (CLI) for worker/queue health dashboard.

Control (MCP-callable)

cancel_job id=ID
replay_job id=ID

replay_job is not protected — only shell submission is. Agents can cancel or replay a shell job without CLI access.

Use idempotency keys for recurring shell workloads to avoid duplicate runs.

Subagent Jobs (LLM Orchestration)

Use for open-ended reasoning, tool-using research, and fan-out synthesis.

User-facing entrypoint: gbrain agent run <prompt> is the canonical way to submit subagent work. It handles the elevated-trust plumbing — subagent and subagent_aggregator are both in PROTECTED_JOB_NAMES, so direct MCP submission requires {allowProtectedSubmit: true}, which gbrain agent run supplies.

Phase 1: Submit

gbrain agent run "Research Acme Corp revenue" --tools "search,query"

--tools accepts a comma-separated subset of BRAIN_TOOL_ALLOWLIST (see src/core/minions/tools/brain-allowlist.ts): query, search, get_page, list_pages, file_list, file_url, get_backlinks, traverse_graph, resolve_slugs, get_ingest_log, put_page. Anything outside the allow-list is rejected at submit time with allowed_tools references unknown tool.

For parallel work with a fan-out manifest:

gbrain agent run --fanout-manifest companies.json

The manifest describes N children + 1 aggregator. Each child runs name="subagent" under the hood; the aggregator runs name="subagent_aggregator" and claims AFTER every child terminates. See src/core/minions/handlers/subagent.ts and src/core/minions/handlers/subagent-aggregator.ts.

Flags (from src/commands/agent.ts):

• --subagent-def <name> — named subagent definition
• --model <id> — override model
• --max-turns <N> — cap the LLM loop
• --tools <csv> — allow-listed brain tools (see above)
• --timeout-ms <N> — hard timeout per job
• --fanout-manifest <file> — N children + 1 aggregator
• --follow / --no-follow — stream logs + wait (default on TTY)
• --detach — submit and return immediately

Queue/priority/retry tuning is not exposed by gbrain agent run; submit the raw subagent handler via gbrain jobs submit (requires CLI trust) if you need those knobs.

Phase 2: Monitor

list_jobs --status active          # MCP — what's running?
get_job ID                         # MCP — full details + logs + tokens
get_job_progress ID                # MCP — structured progress snapshot
gbrain jobs stats                  # CLI — queue health dashboard
gbrain agent logs ID --follow      # CLI — streaming transcript + heartbeat

Progress includes: step count, total steps, message, token usage, last tool called.

Phase 3: Steer

Send a message to redirect a running agent:

send_job_message id=ID payload={"directive":"focus on revenue, skip headcount"}

The agent handler reads inbox messages on each iteration and injects them as context. Messages are acknowledged (read receipts tracked).

Only the parent job or admin can send messages (sender validation).

Phase 4: Lifecycle

pause_job id=ID                    # freeze without losing state
resume_job id=ID                   # pick up where it left off
cancel_job id=ID                   # hard stop
replay_job id=ID                   # re-run with same or modified params
replay_job id=ID data_overrides={"depth":"deep"}  # replay with changes

All lifecycle ops are MCP-callable.

Phase 5: Review Results

get_job ID                         # result, token counts, transcript

Token accounting: every job tracks tokens_input, tokens_output, tokens_cache_read. Child tokens roll up to parent automatically on completion.

Output Format

When reporting job status to the user:

Job #ID (name) — status
Progress: step/total — last action
Tokens: input_count in / output_count out (+ cache_read cached)
Runtime: Xs
Children: N pending, M completed

When reporting completion:

Job #ID completed in Xs
Tokens used: input / output / cache_read
Result: <summary>

When reporting batch status (parent with children):

Parent #ID — waiting-children
  #A subagent(Acme) — active, 3/5 steps, 2.5k tokens
  #B subagent(Beta) — completed, 1.8k tokens
  #C subagent(Gamma) — paused
Total tokens so far: 4.3k

Anti-Patterns

• Don't spawn a Minion for a single search query (use search tool directly)
• Don't fire-and-forget without checking results
• Don't spawn > 5 concurrent agents without checking gbrain jobs stats first
• For subagent work, don't use sessions_spawn with runtime: "subagent" when Minions is available (use gbrain agent run instead)
• Don't poll get_job in a tight loop (use get_job_progress for lightweight checks)

Tools Used

• Submit a background job — submit_job (MCP, non-protected names only; shell jobs are CLI-only, subagent jobs via gbrain agent run)
• Get job details — get_job (MCP)
• List jobs with filters — list_jobs (MCP)
• Cancel a job — cancel_job (MCP)
• Pause a job — pause_job (MCP)
• Resume a paused job — resume_job (MCP)
• Replay a completed/failed job — replay_job (MCP)
• Send sidechannel message — send_job_message (MCP)
• Get structured progress — get_job_progress (MCP)
• Queue stats — gbrain jobs stats (CLI; no MCP equivalent)

Source: garrytan/gbrain → skills/minion-orchestrator/SKILL.md