Nested Agents

Nested Sub-Agents — Guardrails

Pipeline agents with Agent may dispatch helpers one level further down. These rules are non-negotiable.

Optimization, never a dependency

If Agent is missing, dispatch fails, or results never arrive, do the work yourself inline and proceed. Never fail solely because nesting is unavailable (principle-optimization-never-dependency). Spawn only when bulk reading or tracing would add context you will not reuse; use targeted Reads/Greps directly otherwise.

Version gate — confirm before the first nested dispatch

Nested dispatch requires Claude Code >= 2.1.172. Agent tool presence is the universal gate, including for agents without Bash. With Bash, run once:

node "${CLAUDE_PLUGIN_ROOT}/skills/nested-agents/supports-nesting.mjs" "$(claude --version)"

Only supported with exit 0 permits nesting for the turn. Any non-zero, older or unrecognizable version, or unavailable check is unsupported: fail-closed, do not spawn, and work inline (principle-fail-closed).

Dispatch invariants

• Helpers are read-only: built-in Explore, team:file-finder, or general-purpose with an explicitly read-only prompt. They NEVER write files, commit, or write under docs/plans/; the parent or orchestrator writes artifacts.
• Every call passes model:: haiku for location, grep, and bulk reading; sonnet for subsystem traces or claim checks; opus only after a sonnet helper was inconclusive, with that failure named. Effort: low for lookups, medium for tracing, never xhigh.
• You are at depth 2 of 5. Spawn at most ONE more level; every helper must work directly and never spawn (principle-deep-agents-narrow-seams).
• Helpers never ask users. Resolve ambiguity or record it in your artifact's open questions/assumptions (principle-record-assumptions).
• At most 4 helpers may be in flight. Dispatch independent work in parallel. Bound each response. Spot-verify every reported claim; you own it.
• Use SendMessage for an in-scope follow-up to a live scout when available; it uses the same cap and reply bound. Otherwise respawn. Skeptics are always fresh and one-shot: one skeptic per claim (principle-generator-evaluator).

Verification helpers get neutral claims

Apply principle-blind-the-investigator: send a neutral, falsifiable claim with file:line, never your verdict, severity, or reasoning, and ask the helper to refute it. A rule-violation claim carries the rule cited at skills/<skill>/SKILL.md. Stated rule outranks observed precedent; only a mismatched rule or an allowed case declared by that rule refutes the claim. Follow skills/systems-thinking/SKILL.md only where no written rule speaks. Drop or downgrade only a REFUTED result whose evidence you verify. Inconclusive means CONFIRMED. List removals under ### Refuted by verification.

Before researcher, implementer, code-reviewer, or security-reviewer dispatches helpers, read references/per-agent-dispatch.md for exact types, prompt contents, templates, caps, and fallback rules.

code-reviewer — vendor couriers (cross-model pass)

Each vendor run uses one read-only Explore courier named codex-review or agy-review, per skills/cross-model-review/SKILL.md. Couriers return stdout, write and spawn nothing, and count toward the 4-helpers-in-flight cap. The vendor process follows that skill's pinned argv, env allowlist, post-pass tree check, and inline fallback.