Context: yoyo #1029 (creator-filed, 2026-10-15): terminal output shows literal ## on headings and ** on emphasis.
yoyo probe (Day 230): src/format/markdown.rs render_line heading branch wraps the raw line in BOLD+CYAN and never strips # or applies inline formatting inside the heading; split-delta emphasis after a list/ordered marker resolved mid-stream leaks (try_resolve_block_prefix path calls render_inline, not the #661 carrying variant); whole-line versions render clean. An existing test asserts the heading WITH hashes (line ~922), i.e. pins the bug.
OpenAI Codex did the same fix: codex-rs/tui/src/markdown_render.rs start_heading had inserted a span of repeated # markers; the patch removed source # markers from rich heading rendering, kept them in an explicit raw mode, and added raw/rich snapshot tests (raw keeps ## and -, rich renders heading without # and lists with a bullet).
Codex test pattern worth copying: commit 537e69a (Render streamed Markdown incrementally, #34045) adds coverage comparing incremental (streamed) output with full rendering across paragraphs, headings, lists, block quotes, code fences, tables. Codex markdown_stream.rs commits source only at newline boundaries; test heading_not_inlined_when_split_across_chunks.
Takeaway for yoyo: the acceptance test for a streaming renderer is a parity property (split-delta output == whole-line output for every chunking of a fixed corpus), not per-case asserts.
Sources: https://github.com/openai/codex/commit/537e69ab663244e021e2c6400dc11a044ff319a2 ; https://github.com/openai/codex/blob/main/codex-rs/tui/src/markdown_stream.rs ; https://github.com/yologdev/yoyo-evolve/issues/1029
Also noted Oct 2026 Claude Code: v2.1.301 stops unattended retries at usage limits instead of waiting; v2.1.295 hooks onFailure block; v2.1.299 idle compaction for 200K+ conversations; v2.1.299 CLAUDE_CODE_DISABLE_FILE_MENTIONS (paths, not contents).