diff --git a/CHANGELOG.md b/CHANGELOG.md
index f873760..67632d0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
+- **Comprehensive documentation suite** — 4 new docs: `architecture.md` (end-to-end system architecture with component hierarchy, data flow, IPC patterns), `sidecar.md` (multi-provider runner lifecycle, env stripping, NDJSON protocol, build pipeline), `orchestration.md` (btmsg messaging, bttask kanban, agent roles, wake scheduler, session anchors, health monitoring), `production.md` (sidecar supervisor, Landlock sandbox, FTS5 search, plugin system, secrets management, notifications, audit logging, error classification, telemetry)
 - **Sidecar crash recovery/supervision** — `bterminal-core/src/supervisor.rs`: SidecarSupervisor wraps SidecarManager with auto-restart, exponential backoff (1s base, 30s cap, 5 retries), SidecarHealth enum (Healthy/Degraded/Failed), 5min stability window. 17 tests
 - **Notification system** — OS desktop notifications via `notify-rust` + in-app NotificationCenter.svelte (bell icon, unread badge, history max 100, 6 notification types). Agent dispatcher emits on complete/error/crash. notifications-bridge.ts adapter
 - **Secrets management** — `keyring` crate with linux-native (libsecret). SecretsManager in secrets.rs: store/get/delete/list with `__bterminal_keys__` metadata tracking. SettingsTab Secrets section. secrets-bridge.ts adapter. No plaintext fallback
diff --git a/docs/task_plan.md b/docs/task_plan.md
index 908c114..626f464 100644
--- a/docs/task_plan.md
+++ b/docs/task_plan.md
@@ -110,6 +110,16 @@ See [phases.md](phases.md) for the full phased implementation plan.
 - **Post-MVP:** Phases 5-7 (agent tree, polish, packaging, agent teams)
 - **Multi-Machine:** Phases A-D (bterminal-core extraction, relay binary, RemoteManager, frontend)
 
+## Related Documentation
+
+For the current (v3) architecture, see these documents which supersede parts of this v2 plan:
+
+- **[architecture.md](architecture.md)** — End-to-end system architecture (Rust backend, Svelte frontend, sidecar layer)
+- **[sidecar.md](sidecar.md)** — Multi-provider sidecar architecture (Claude, Codex, Ollama runners)
+- **[orchestration.md](orchestration.md)** — Multi-agent orchestration (btmsg, bttask, wake scheduler)
+- **[production.md](production.md)** — Production hardening features (supervisor, sandbox, search, plugins, secrets)
+- **[v3-task_plan.md](v3-task_plan.md)** — v3 Mission Control architecture decisions
+
 ---
 
 ## Decisions Log