# Phase 155 Summary

Status: implemented in working tree

## Goal

Close the next post-`v1.80` gap by turning enacted route handoff into an
operator-visible transition-receipt surface instead of leaving completed
source-to-target route change implicit after transition intent.

## What Landed

- route transition-receipt payload construction and runtime/read-path rendering
  in:
  - `research/knowledge-hub/knowledge_hub/runtime_read_path_support.py`
- runtime protocol rendering for the new transition-receipt section in:
  - `research/knowledge-hub/knowledge_hub/kernel_markdown_renderers.py`
  - `research/knowledge-hub/knowledge_hub/runtime_bundle_support.py`
- replay support for pending versus recorded versus none route-transition
  receipt visibility in:
  - `research/knowledge-hub/knowledge_hub/topic_replay.py`
- public runtime-bundle schema coverage for `route_transition_receipt` 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_transition_receipt_acceptance.py`
- new contract/runtime coverage in:
  - `research/knowledge-hub/tests/test_hypothesis_route_transition_receipt_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 `155` now closes the first bounded route transition-receipt slice:

- `status --json` and the runtime protocol note now surface one
  `route_transition_receipt` summary with `pending`, `recorded`, and `none`
  states
- `replay-topic --json` exposes the same transition-receipt payload plus the
  route-transition-receipt status on both current-position and conclusions lanes
- the new isolated acceptance proves AITP can distinguish intended handoff with
  no durable receipt yet, intended handoff durably recorded in transition
  history, and no applicable handoff, without widening into fresh runtime
  mutation
