---
id: T02
parent: S02
milestone: M014
provides: []
requires: []
affects: []
key_files: ["backend/pipeline/test_harness.py"]
key_decisions: ["Compose accepts both harness output (with .pages[]) and raw SynthesizedPage JSON", "New moment indices built manually with offset to ensure correct [N+i] numbering"]
patterns_established: []
drill_down_paths: []
observability_surfaces: []
duration: ""
verification_result: "compose --help exits 0 with correct argument listing. build_compose_prompt() smoke test verified XML tag presence, correct index offsets, and creator tag content."
completed_at: 2026-04-03T01:05:22.034Z
blocker_discovered: false
---

# T02: Added compose subcommand with build_compose_prompt(), run_compose(), and CLI wiring for offline composition testing

> Added compose subcommand with build_compose_prompt(), run_compose(), and CLI wiring for offline composition testing

## What Happened
---
id: T02
parent: S02
milestone: M014
key_files:
  - backend/pipeline/test_harness.py
key_decisions:
  - Compose accepts both harness output (with .pages[]) and raw SynthesizedPage JSON
  - New moment indices built manually with offset to ensure correct [N+i] numbering
duration: ""
verification_result: passed
completed_at: 2026-04-03T01:05:22.034Z
blocker_discovered: false
---

# T02: Added compose subcommand with build_compose_prompt(), run_compose(), and CLI wiring for offline composition testing

**Added compose subcommand with build_compose_prompt(), run_compose(), and CLI wiring for offline composition testing**

## What Happened

Added build_compose_prompt() (builds user prompt with XML tags and offset-based citation indices), run_compose() (loads existing page + two fixtures, calls LLM, validates output, logs compose-specific metrics), and the compose CLI subcommand with --existing-page, --fixture, --existing-fixture args plus optional prompt/output/category/model/modality overrides.

## Verification

compose --help exits 0 with correct argument listing. build_compose_prompt() smoke test verified XML tag presence, correct index offsets, and creator tag content.

## Verification Evidence

| # | Command | Exit Code | Verdict | Duration |
|---|---------|-----------|---------|----------|
| 1 | `cd backend && python -m pipeline.test_harness compose --help` | 0 | ✅ pass | 500ms |
| 2 | `python -c build_compose_prompt assertions (XML tags, index offsets, creator)` | 0 | ✅ pass | 400ms |


## Deviations

None.

## Known Issues

None.

## Files Created/Modified

- `backend/pipeline/test_harness.py`


## Deviations
None.

## Known Issues
None.
