[BUG] Artifacts gallery omits every Claude Code artifact older than ~2 Sep 2026 (artifacts still exist and open)

## Summary

On a personal Max account, the gallery at `claude.ai/code/artifacts` (All tab) lists Claude Code artifacts only back to **2 Sep 2026**. Everything published before that is missing, even though those artifacts **still exist and open normally** from their links. Directly below the 2 Sep rows, the gallery shows claude.ai chat artifacts from 2025 ("October 2025", "July 2025", "June 2025"). That makes the list look complete when it isn't.

The docs say the gallery "lists every artifact you have created" ([Share session output as artifacts](https://code.claude.com/docs/en/artifacts)), so this looks like a bug, not a design choice.

## What I see

- Claude Code rows (`` icon) run from today down to rows labelled "Viewed Sep 2" / "Edited Sep 2", then stop.
- The next section is "October 2025" (chat artifacts), then July and June 2025.
- Claude Code artifacts published between mid-July and 1 Sep 2026 are absent, including one I shared with clients on 1 Sep.
- Searching the gallery by the missing artifact's exact title doesn't find it.

## Evidence the artifacts still exist

- An artifact published on 19 Aug 2026 and another from 1 Sep 2026 both open from their `claude.ai/code/artifact/` links while signed in as the owner. The Artifact tool's `read` action reports both as "owned by you".
- So this isn't the deletion described in #87796: these links work, they just aren't listed.
- Not a retention policy: this is a personal Max account, and retention settings exist only for Team and Enterprise.

## A related observation

The Artifact tool's `list` action (`limit: 50`, the maximum, `scope: "mine"`) also bottoms out at an artifact updated **2026-09-02**, with no way to page further back. The gallery and the tool may share the same single-page query.

## Viewing a missing artifact brings it back

I opened the missing 1 Sep artifact from its link, then reloaded the gallery. It now appears at the top of "Today" as "Viewed 2m ago", where before it was absent entirely. So the artifact and its ownership are fine; only the listing leaves it out.

## Why the gap is hidden

The rows below the cut-off are **claude.ai chat artifacts** (different icon, "Edited "). The gallery appears to merge two sources: every chat artifact, plus only a recent subset of Claude Code (``) artifacts. Only the Claude Code source is truncated, so the full chat list underneath makes the gallery look complete.

## Likely cause: an activity cutoff, not a page cap

I checked whether bringing that artifact back pushed the oldest Claude Code row off the bottom, which would happen if the gallery loaded one fixed-size page sorted by activity. **It didn't.** The last Claude Code row ("Viewed Sep 2") is still there, directly above "October 2025".

So the gallery appears to include only Claude Code artifacts that have a viewed/edited timestamp from about 2 Sep 2026 onward. Artifacts nobody has opened since then are left out, even though the account owns them.

The workaround (open each missing artifact's link once) only works if you still have the link, which is exactly what the gallery is for.

## Steps to reproduce

1. Have Claude Code artifacts published both before and after early September 2026.
2. Open `claude.ai/code/artifacts`, All tab, and scroll to the end of the Claude Code rows.
3. Artifacts older than about 2 Sep are missing, but opening their links directly still works.

## Expected

Every artifact the account owns appears in the gallery and in the Artifact tool's `list`, with pagination if needed.

## Environment

- Plan: Max (personal account)
- Claude Code CLI 2.1.259; Claude desktop app 1.52386.6; macOS 26.6.2
- Browser: Safari
- Artifact IDs available privately on request.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Start by reproducing the cutoff in claude.ai/code/artifacts and compare it with the Artifact tool's list action using limit 50 and scope "mine". Trace how those two entry points enumerate owned artifacts; done means all owned artifacts appear, with pagination when needed, without requiring each artifact to be opened first.

Written by the indexing model from the issue text.