Add subagent foundation and runtime events

AGENTS.md

@@ -44,6 +44,8 @@ src/
 ├── cache/         # Tool result caching (LRU, Redis) — src/cache/AGENTS.md
 ├── middleware/    # AI SDK language model middleware — src/middleware/AGENTS.md
 ├── utils/         # Budget, compaction, context status, helpers — src/utils/AGENTS.md
+├── subagents/     # Subagent control plane foundation — src/subagents/AGENTS.md
+├── runtime/       # Runtime events, plan state, approvals, snapshots — src/runtime/AGENTS.md
 ├── skills/        # Agent Skills standard — src/skills/AGENTS.md
 ├── setup/         # Agent environment setup (sandbox bootstrapping) — src/setup/AGENTS.md
 ├── cli/           # CLI initialization — src/cli/AGENTS.md
@@ -293,5 +295,7 @@ See `src/tools/AGENTS.md` for per-tool config details.
 | Add middleware | `src/middleware/AGENTS.md` → "Common Modifications" |
 | Add a cache backend | `src/cache/AGENTS.md` → "Common Modifications" |
 | Add a context layer or prompt section | `src/context/AGENTS.md` → "Common Modifications" |
+| Add subagent foundation behavior | `src/subagents/AGENTS.md` → "Common Modifications" |
+| Add runtime events, plan state, approvals, or snapshots | `src/runtime/AGENTS.md` → "Common Modifications" |
 | Add a skill source | `src/skills/AGENTS.md` → "Common Modifications" |
 | Add a config field | Define in `src/types.ts`, consume in the relevant factory via `config?.yourField ?? default` |

CHANGELOG.md

@@ -0,0 +1,22 @@
+# Changelog
+
+## Unreleased
+
+### Breaking
+
+- `createAgentTools` now has a binary coding surface: configure `codemode` to expose Codemode as the parent coding tool, or omit `codemode` to expose direct BashKit tools.
+- Removed the legacy `Task` tool. Use `SpawnAgent` plus `WaitAgent`.
+- Removed the legacy `TodoWrite` tool. Use `UpdatePlan`.
+
+### Added
+
+- Added controller-backed subagent tools and host-facing control panel state.
+- Added profile-scoped subagent policies for tool allowlists, denied-tool behavior, Codemode exposure, context inheritance, and cost/depth/concurrency limits.
+- Added JSON-safe subagent profile loading helpers: `loadSubagentProfilesFromObject`, `loadSubagentProfilesFromJson`, and `loadSubagentProfilesFromFile`.
+- Added normalized runtime events for tool execution, plan updates, approvals, file changes, command output, and agent lifecycle snapshots.
+
+### Migration
+
+- Replace one-shot `Task` flows with `SpawnAgent({ task, task_name })` followed by `WaitAgent({ agent })`.
+- Replace `TodoWrite` with `UpdatePlan`.
+- When adopting Codemode, move direct tool policy into Codemode `includeTools` / `excludeTools` and subagent profile policies.