---
model: openai/gpt-5.6-sol
service: opencode
timestamp: 2026-08-28T19:50:32+00:00
git_ref: 9115d24d
diff_cmd: git diff HEAD~1..HEAD
---

The response implemented and analyzed the requested FSP backfill fix.

> `git diff HEAD~1..HEAD -- piker/fsp/_api.py`
>
> `git diff HEAD~1..HEAD -- piker/fsp/_engine.py`
>
> `git diff HEAD~1..HEAD -- piker/fsp/_momo.py`
>
> `git diff HEAD~1..HEAD -- piker/fsp/_volume.py`
>
> `git diff HEAD~1..HEAD -- piker/data/ticktools.py`
>
> `git diff HEAD~1..HEAD -- piker/data/_sharedmem.py`
>
> `git diff HEAD~1..HEAD -- piker/ui/_dataviz.py`
>
> `git diff HEAD~1..HEAD -- piker/ui/_pg_overrides.py`
>
> `git diff HEAD~1..HEAD -- piker/ui/_fsp.py`
>
> `git diff HEAD~1..HEAD -- tests/test_fsp_sync.py`
>
> `git diff HEAD~1..HEAD -- .agents/skills/piker-fsp-expert/`

The generated implementation distinguishes history revisions from sample
advancement, filters foreign backfill events, computes historical output from
an immutable source snapshot, and targets FSP-backed visualizations for cache
invalidation, redraw, and y-range updates. It also establishes a typed FSP
stream protocol, normalizes the dormant scalar built-ins to that protocol,
and adds deterministic regression coverage. The typing review replaces
arbitrary redraw kwargs with an explicit boolean control, records the
concrete piker graphics object chain, and introduces reusable normalized
quote, tick, and SHM-token message shapes.

The generated skill bundle records the FSP runtime architecture, financial
signal-processing principles, testing matrix, roadmap issues, and candidate
numerics and IPC research projects.

Verification reported by the response:

- focused FSP and deterministic history tests passed;
- Ruff passed for all changed Python files;
- focused `ty` checks passed for tick and scalar FSP contracts;
- compileall passed for all changed Python files;
- `git diff --check` passed;
- repeated read-only code review found no remaining actionable findings.