---
id: TASK-238.7
title: Split src/main.ts into boot-phase services, runtimes, and handlers
status: Done
assignee: []
created_date: '2026-03-27 00:00'
updated_date: '2026-03-27 22:45'
labels:
  - tech-debt
  - runtime
  - maintainability
  - architecture
milestone: m-0
dependencies:
  - TASK-238.6
references:
  - src/main.ts
  - src/main/boot/services.ts
  - src/main/boot/runtimes.ts
  - src/main/boot/handlers.ts
  - src/main/runtime/composers
parent_task_id: TASK-238
priority: high
---

## Description

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After the remaining inline runtime logic and composer gaps are extracted, `src/main.ts` should be split along boot-phase boundaries so the entrypoint stops mixing service construction, domain runtime composition, and handler wiring in one file. This task tracks that structural split: move service instantiation, runtime composition, and handler orchestration into dedicated boot modules, then leave `src/main.ts` as a thin lifecycle coordinator with clear startup-path selection.
<!-- SECTION:DESCRIPTION:END -->

## Acceptance Criteria

<!-- AC:BEGIN -->
- [x] #1 Service instantiation lives in a dedicated boot module instead of a large inline setup block in `src/main.ts`.
- [x] #2 Domain runtime composition lives in a dedicated boot module, separate from lifecycle and handler dispatch.
- [x] #3 Handler/composer invocation lives in a dedicated boot module, with `src/main.ts` reduced to app lifecycle and startup-path selection.
- [x] #4 Existing startup behavior remains unchanged across desktop and headless flows.
- [x] #5 Focused tests cover the split surfaces, and the relevant runtime/typecheck gate passes.
<!-- AC:END -->

## Implementation Plan

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Recommended sequence:

1. Re-scan `src/main.ts` after TASK-238.6 lands and mark the remaining boot-phase seams by responsibility.
2. Extract service instantiation into `src/main/boot/services.ts` or equivalent.
3. Extract runtime composition into `src/main/boot/runtimes.ts` or equivalent.
4. Extract handler/composer orchestration into `src/main/boot/handlers.ts` or equivalent.
5. Shrink `src/main.ts` to startup-path selection, app lifecycle hooks, and minimal boot wiring.
6. Verify the split with focused entrypoint/runtime tests first, then run the broader runtime gate if the refactor crosses startup boundaries.

Guardrails:

- Keep the split behavior-preserving.
- Prefer small boot modules with narrow ownership over a new monolithic bootstrap layer.
- Do not reopen the inline logic work already tracked by TASK-238.6 unless a remaining seam truly belongs here.
<!-- SECTION:PLAN:END -->

## Implementation Notes

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Added boot-phase modules under `src/main/boot/`:
`services.ts` for config/user-data/runtime-registry/overlay bootstrap service construction,
`runtimes.ts` for named runtime/composer entrypoints and grouped boot-phase seams,
and `handlers.ts` for handler/composer boot entrypoints.

Rewired `src/main.ts` to source boot-phase service construction from `createMainBootServices(...)` and to route runtime/handler composition through boot-level exports instead of keeping the entrypoint as the direct owner of every composition import.

Added focused tests for the new boot seams in
`src/main/boot/services.test.ts`,
`src/main/boot/runtimes.test.ts`,
and `src/main/boot/handlers.test.ts`.

Updated internal architecture docs to note that `src/main/boot/` now owns boot-phase assembly seams so `src/main.ts` can stay centered on lifecycle coordination and startup-path selection.
<!-- SECTION:NOTES:END -->

## Final Summary

<!-- SECTION:FINAL_SUMMARY:BEGIN -->
TASK-238.7 is complete. Verification passed with focused boot tests, `bun run typecheck`, `bun run test:fast`, and `bun run build`. `src/main.ts` still acts as the composition root, but the boot-phase split now moves service instantiation, runtime composition seams, and handler composition seams into dedicated `src/main/boot/*` modules so the entrypoint reads more like a lifecycle coordinator than a single monolithic bootstrap file.

Backlog completion now includes changelog artifact `changes/2026-03-27-task-238.7-main-boot-split.md` for the internal runtime architecture pass.
<!-- SECTION:FINAL_SUMMARY:END -->