Retained coordination and prompt patterns

Product decision. Do not “clean up” the coordination + prompt keepers below. Do not confuse them with settings UX that was cut (model-selection matrix, role-based routing popups — replaced by the shipped model-slots-plus-3-knob-compaction design, see Compaction & project memory and Models, roles, and profiles).

This page is a keep/cut ledger carried forward from the pre-fork planning notes. The keep/cut decisions are sound; the module pointers below have been re-grounded on the real TypeScript tree — the original notes pointed at an archived Rust/codex layout (crates/core/src/..., multi_agents_v2, RoleModelSetting) that was never the shipped engine for this product.

KEEP — coordination + prompts

These are genuinely good patterns. Refactors must preserve behavior.

1. Handoff / compaction prompt — packages/agent/src/compaction/compaction.ts (renderHandoffPrompt, generateHandoffFromContext), called from packages/coding-agent/src/session/agent-session.ts. Preserves task continuity across compaction when compaction.type is handoff (the other user-facing type is snap; see Compaction & project memory). Engineering detail: docs/handoff-generation-pipeline.md.
2. Subagent spawn model — packages/coding-agent/src/task/executor.ts (spawn, per-model concurrency semaphore, soft output-budget steering notice, background output capture) plus packages/coding-agent/src/task/agents.ts (bundled subagent definitions) and the task tool registered in packages/coding-agent/src/tools/index.ts.
3. Addressed inter-agent messaging — the irc tool (packages/coding-agent/src/tools/irc.ts, bus in packages/coding-agent/src/irc/bus.ts): send/wait/inbox/list ops, delivery receipts, reply-to threading. This is the shipped equivalent of the old point-to-point InterAgentCommunication/send_message/wait model — send wakes an idle recipient with a real turn, revives a parked one via the lifecycle manager, or injects a non-interrupting aside into a busy one (the wake-now-vs-defer split the old notes called steeringQueue/followUpQueue). Parent steering-hint prompt text lives in packages/coding-agent/src/prompts/steering/{parent-irc,user-interjection}.md. A richer IRC-style, full multi-agent dashboard (channels, not just the message bus) remains Spec — not shipped (BACKLOG U4-10, beyond the /cockpit MVP) — the messaging primitive itself is built; the dashboard UI around it is not.
4. Subagent + todo-list interaction model — the todo tool (packages/coding-agent/src/tools/todo.ts) plus plan-mode guardrails (packages/coding-agent/src/tools/plan-mode-guard.ts). Agents maintain a checklist across multi-step work; this model is frozen and any TUI presentation work extends it without replacing it.

CUT — confusing settings / model-selection UX

These are not keepers. Do not preserve them when condensing settings; they were already replaced by the shipped model-slots-plus-3-knob-compaction design (see Compaction & project memory).

1. Role-based model-selection matrix and per-role popups. Superseded by the shipped design: the interactive model via /model, plain subagent.model and compaction.model fields in settings. default is not a model or a role — see packages/coding-agent/src/config/model-roles.ts and packages/coding-agent/src/config/model-resolver.ts.
2. Silent per-role heuristic routing. The primary model drives everything unless the plain subagent/compaction fields say otherwise; there is no hidden per-role auto-pick behind the scenes.
3. Overlapping compaction settings UX. Condensed to three fields: threshold, type (handoff/snap), model — see packages/coding-agent/src/config/compaction-strategy.ts and the compaction.* group in packages/coding-agent/src/config/settings-schema.ts. Not a parallel model-picker maze.
4. Hosted Cloud/Ultra task-list backend types. Out of scope for this product; do not conflate with the todo tool above.

Coordination vs settings — the confusion line

Rule for future refactors: if a change touches subagent spawning, irc messaging, or the compaction handoff prompt, preserve behavior. If it touches model-routing settings knobs, follow the shipped model-slots design above — do not resurrect a role→model matrix because an old fork had one.