Bug Description

The WeChat personal client (connected via iLink Bot API) renders Markdown tables as scrollable containers, but clips/hides content beyond the visible viewport on the right side. Users can scroll horizontally within the table, but the rightmost columns are cut off and invisible.

This is a WeChat client-side rendering bug in its Markdown/CSS Webview engine, not a Hermes transport issue.

Hermes Transport Layer Status

Hermes is correctly preserving Markdown tables as-is since v2026.4.23 (PR #11571, commit 6ee65b4d):

1. format_message() -> _normalize_markdown_blocks() -> preserves Markdown tables
2. _send_message() -> sends raw Markdown text to iLink API
3. _rewrite_table_block_for_weixin() exists but is dead code (never called)

The Markdown arrives intact at the WeChat client. The clipping happens during rendering.

Steps to Reproduce

1. Send a Markdown table with 3+ columns to a WeChat contact via the Weixin adapter
2. Open the message in WeChat personal client (Windows / macOS / mobile)
3. The table renders as a scrollable container
4. Scroll right -> right-side columns are clipped/invisible

Expected Behavior

All table columns should be visible when scrolling, or the table should expand to fit content.

Actual Behavior

Columns beyond the initial visible width are clipped. The scrollable container exists but does not reveal all content.

Environment

Workaround

Generate table images using table-image-generator skill and send as native images via MEDIA::

node ~/.hermes/skills/creative/table-image-generator/scripts/table.mjs \
  --data '[{"Col A":"val","Col B":"val","Col C":"val"}]' \
  --output table.png --dark --scale 2

Then include MEDIA:/path/to/table.png in the agent response.

Proposed Mitigation (Hermes-side)

Since this is a client-side bug outside Hermes' control, the recommended mitigation is to update the Weixin platform hint in prompt_builder.py to instruct the agent to:

1. Use table images (via table-image-generator skill) for tables with 3+ columns or wide content
2. Use list format (key: value) for simple 2-column tables
3. Avoid pipe tables in Weixin responses until the WeChat client fixes its rendering

Related Issues / PRs

• Closes (transport): Weixin adapter still rewrites Markdown tables/headers/links instead of preserving native WeChat Markdown rendering #10308 - Weixin adapter still rewrites Markdown tables
• PR fix(weixin): Batch-3 salvage — voice fallback, MEDIA extraction, native markdown rendering #11571 - fix(weixin): preserve native markdown rendering (v2026.4.23)
• PR fix(weixin): preserve native markdown rendering #10338 - Original fix PR (merged via fix(weixin): Batch-3 salvage — voice fallback, MEDIA extraction, native markdown rendering #11571)
• [Bug]: Regression: WeChat message formatting changed from structured tables to fragmented bubbles #7468 - Regression: tables fragmented into bubbles (fixed in earlier release)
• [Feature]: Proposal: Simplifying the Message Delivery Logic for the Weixin Adapter简化微信接口的消息交付逻辑 #9612 - Proposal: simplify Weixin message delivery logic