design-council

design-council

Convene a parallel team of role-specialized agents to debate a non-trivial technical decision (or audit a codebase in Review mode) in real time. The invoking Claude is CEO: convenes, routes peer-DMs, arbitrates deadlocks, writes a one-page decision log. Every teammate has its own context — not a subagent inheriting yours — so disagreement is structural, not simulated.

What the user sees

1. Plan card. Before any seat spawns, the CEO shows a one-screen card: mode, roster, per-seat model, rough token/wall-clock budget, drafted opening question. You reply go, swap X for Y, drop X, add X, or abort.
2. Handshake status. After spawn, the CEO emits one line — e.g. HANDSHAKE: 8/8 ok | verdict=PROCEED — so you know every seat actually started.
3. Cross-talk. Seats post opening verdicts, DM each other to debate, CEO routes deadlocks. Bounded: 3 rounds max.
4. Log preview. Before saving, the CEO posts the draft decision log to chat. Reply save, amend <note>, or discard.
5. Output. One-page decision log at ~/.claude/councils/<yyyy-mm-dd>-<slug>/log.md (outside any repo).
6. Stop early. Say "stop the council" at any phase — CEO broadcasts shutdown, saves a status: halted partial log, cleans up.

Invocation: /design-council:design-council [decision-or-focus] or any of the trigger phrases below.

When to invoke

Both conditions must hold: (a) decision or review crosses ≥2 specialist domains, and (b) output must survive handoff — a decision log, tracker items, or an execution plan. Natural triggers: "convene the council", "design debate", "council review", "run a design review", "debate this design", "get the team together".

Do NOT invoke for: bug fixes, single-specialist questions, library/tool picks, pure exploration (→ Explore), one-turn sanity checks.

Default roster (size matches decision shape)

#	Slug	Owns
1	principal-engineer	Architecture, module boundaries, simplicity (opens the debate)
2	platform-engineer	Systems, infra, data shape, operational cost, observability
3	integration-engineer	Downstream consumers, third-party developers, backwards compat
4	test-engineer	TDD, mutation ritual, coverage, assertion hygiene
5	qa-engineer	User flows ↔ spec alignment, regression surface, manual test plan
6	security-engineer	Input validation, secrets, path safety, error sanitization
7	performance-engineer	Batching, memory, concurrency, measurement-before-optimization
8	product-manager	UX alignment, product coherence, best-practice conformance
9	ui-ux-designer	Ergonomics, visual consistency, interaction design
10	accessibility-specialist	a11y, keyboard nav, screen reader, contrast
11	technical-writer	Docs, in-app help, CHANGELOG, API reference

Opt-ins: devops-engineer (deploy risk, CI/CD, rollback), sre-engineer (production reliability, SLOs, blast radius, rollback validation; pair with devops-engineer when production stakes are high), finops-engineer (cloud/API cost, unit economics, resource lifecycle), legal-compliance (privacy, licensing), domain-expert (subject-matter SME), historian (codebase precedent on mature repos).

Dynamic sizing is the default, not an exception. No runtime UI → drop ui-ux + a11y. No user input / no infra → drop security + platform. Internal-tooling defaults can be 4–6 seats. Full 11+opt-ins only when every role-lens applies. The CEO decides at Phase 0 and surfaces the roster in the plan card.

Model choice (state it, don't default quietly)

Default: Opus for synthesis-heavy seats (principal-engineer, product-manager, technical-writer, historian) and Sonnet for analytical seats (test, performance, platform, qa). Override all → Opus on a high-quality-bar framing. The plan card shows which seats got which model; users can adjust before spawn.

Variants

• Debate mode (default) — single decision, verdict tags (APPROVE / CONCERNS / BLOCK), peer DMs resolve disagreements, CEO arbitrates what's left.
• Review mode — codebase audit, P0/P1 findings, cross-talk skipped, CEO dedupes and files tracker items. See references/review-mode.md.

Protocol (six phases)

Phase	Name	CEO does
0	Plan card	Draft roster + models + budget + opening question; show to user; wait for go
1	Brief	Gather binding constraints verbatim (CLAUDE.md, spec, memory, tracker); self-audit — grep auto-memory + prior decision logs for entries about the council skill; flag any memory-vs-skill contradiction and follow memory; write everything to ~/.claude/councils/<slug>/brief.md once; draft opening prompt
2	Convene	TeamCreate + parallel Agent spawns in one multi-tool-call message; every spawn prompt points to brief.md (prompt-cache hits across seats)
2.5	Handshake verify	Count incoming handshake DMs; inspect team config for empty tmuxPaneId; remediate or drop silent-spawn failures; emit HANDSHAKE: N/N ok line
3	Cross-talk	Route peer DMs, ask narrowing questions, bridge converged tracks; 3-round hard cap. Skipped by default in Review mode.
4	Arbitrate	Write decision + rationale for every unresolved disagreement. Escalate strategic/legal/budget to user. Every DEFER needs a revisit criterion + filed tracker item (if a tracker is detected).
5	Log + teardown	Post draft log to chat; on user save, persist to ~/.claude/councils/. Broadcast shutdown_request, wait for acks, TeamDelete.

Full protocol: references/protocol.md. Opening-prompt scaffold: references/opening-prompt-template.md. Decision-log scaffold: references/decision-log-template.md. Role briefs: references/roles/<slug>.md.

Protocol contract for every spawned seat

Every spawn prompt must inline these four delivery rules. Skipping them silently breaks the council:

1. SendMessage(to: "team-lead") is the ONLY channel to the CEO. Plain-text output is invisible.
2. Send a 1-line handshake as the first action. Without it, the seat is indistinguishable from a silent-spawn failure.
3. Final position/findings delivered via SendMessage. Writing as plain text then going idle drops work on the floor. Protocol responses (shutdown_response, plan_approval_response) use their structured JSON form — prose acks don't close the protocol state and will block teardown.
4. Idle-notification summary field is ≤200 chars — do not put substantive content there.

Canonical wording with peer-DM addressing: references/protocol.md Phase 2.

Non-negotiable rules

• Agents are peers with independent contexts. Your conversation is not shared.
• Peer-DM first, CEO-route second. Seats DM each other; CEO routes only tiebreakers, stalls, escalations.
• CEO never takes a seat, never types application code. Orchestration, routing, arbitration, record-keeping only. Shipping uses fresh isolated agents (see references/implementation-handoff.md).
• Opening prompt carries the constraints — baked into brief.md and every spawn prompt. Cannot be forgotten mid-debate.
• Round budget is hard. 3 cross-talk rounds max.
• Every CEO decision is written with rationale. Silence as resolution is banned.
• Decision log lives outside any repo. Default ~/.claude/councils/.
• Scope discipline. Unrelated issues surfaced in debate → new tracker item, never a side-diff.
• Memory beats stale skill text. If a memory entry contradicts a prescription in this file or references/protocol.md, memory wins — it was written after a real failure. Flag the contradiction in brief.md, follow memory, record the drift in the decision log's emergent-insights appendix.

Failure modes this skill guards against

#	Mode	Guard
1	Sequential-thinking regression	Parallel-spawn template is mandatory (Phase 2)
2	Runaway debate	3-round cross-talk cap
3	Silent CEO	Every unresolved item requires written decision
4	Constraint re-discovery mid-debate	brief.md is pre-written and cached
5	Leaked decision logs	Default path is outside any repo
6	Zombie teammates	Teardown is protocol-enforced
7	Silent spawn failure	Phase 2.5 handshake verification
8	Plain-text findings lost to floor	Universal rule #3 in every spawn prompt
9	Silent-promise DEFERs	Phase 5 tracker-ID-or-demote gate

Harness gotchas (worktree cwd leaks, commit-hook races, tracker-state pollution, mixed-base merges, CHANGELOG conflicts) live in references/implementation-handoff.md — loaded only when the CEO reaches the shipping sub-step.

Integrations

• Tracker integration (auto-detected, beads first-class): references/tracker-integration.md.
• Split-pane observability (tmux / iTerm2 via teammateMode setting): optional Claude Code harness feature, not a plugin requirement.

Related skills

• using-agent-skills — meta-skill for skill discovery.
• spec-driven-development — often runs BEFORE a council, to produce the spec being debated.
• planning-and-task-breakdown — often runs AFTER a council, to decompose the decision into implementable tasks.
• beads:beads — tracker commonly used for deferred follow-ups.