---
title: "2026-09-18 Histo embedding artifact API search"
description: "Searched fetched Histo refs for a packaged persistent embedding artifact or serialization API."
image: "https://docs.virdx.dev/img/virdx-social-card.png"
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.virdx.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# 2026-09-18 Histo embedding artifact API search

## Work Done

- Inspected all 159 fetched `origin/*` refs and recent commits in `/Users/felix.knispel/work/histo`.
- Located the September shared embedding extractor commits and compared their API with `histo-v0.0.127`.
- Confirmed that `histo-v0.0.127` packages the in-memory `FeatureGrid`, `extract_embeddings`, and high-level Gleason extraction/decode wrapper.
- Confirmed that no fetched branch adds a stable path-backed embedding artifact, `FeatureGrid` serialization, or package-level save/load API. Persistence search hits belong to experiments and scripts.

## Lessons Learned: Pitfalls

- Method names such as `predict_wsi_embeddings` suggest that embeddings are returned, but the method immediately decodes the grids and returns segmentation arrays.
- Broad commit-subject searches miss the distinction between in-memory extraction and persistent artifact support; source-level searches across every remote tip were necessary.

## Lessons Learned: Improvements

- A short Histo API inventory that distinguishes package APIs from experiment-only persistence would make future integration checks faster.
- Document that `FeatureGrid` is an in-memory dataclass with no serialization contract as of `histo-v0.0.127`.

Source: https://docs.virdx.dev/knowledge/inbox/2026-09-18-histo-embedding-artifact-api-search/index.mdx