# Phase 151 Summary

Status: implemented in working tree

## Goal

Close the next post-`v1.76` gap by turning ready parked-route signals into one
operator-visible route handoff surface.

## What Landed

- route handoff payload construction and runtime/read-path rendering in:
  - `research/knowledge-hub/knowledge_hub/runtime_read_path_support.py`
- runtime protocol and research-question rendering for the new route handoff
  section in:
  - `research/knowledge-hub/knowledge_hub/kernel_markdown_renderers.py`
  - `research/knowledge-hub/knowledge_hub/runtime_bundle_support.py`
- replay support for primary handoff candidates and keep-parked decisions in:
  - `research/knowledge-hub/knowledge_hub/topic_replay.py`
- public runtime-bundle schema coverage for `route_handoff` and
  `route_handoff_item` in:
  - `research/knowledge-hub/runtime/schemas/progressive-disclosure-runtime-bundle.schema.json`
- one new isolated acceptance lane:
  - `research/knowledge-hub/runtime/scripts/run_hypothesis_route_handoff_acceptance.py`
- new contract/runtime coverage in:
  - `research/knowledge-hub/tests/test_hypothesis_route_handoff_contracts.py`
  - `research/knowledge-hub/tests/test_runtime_scripts.py`
  - `research/knowledge-hub/tests/test_topic_replay.py`
  - `research/knowledge-hub/tests/test_schema_contracts.py`
- documentation and runbook updates across:
  - `research/knowledge-hub/README.md`
  - `research/knowledge-hub/runtime/README.md`
  - `research/knowledge-hub/runtime/AITP_TEST_RUNBOOK.md`

## Outcome

Phase `151` now closes the first bounded route handoff slice:

- `status --json`, `research_question.contract.md`, and the runtime protocol
  note now surface one primary parked-route handoff candidate plus explicit
  keep-parked decisions
- `replay-topic --json` exposes the same `route_handoff` payload plus the
  handoff-candidate count and handoff candidate id
- the new isolated acceptance proves one ready parked route can occupy the
  bounded handoff lane while another ready parked route remains explicitly
  parked, without runtime mutation
