Markdown rendering broken since opentui upgrade from 0.1.79 to 0.1.88+

[ars-ppi]

Description

Bug

Markdown in assistant responses is not rendered — headings (###), bold (**text**), code blocks, and inline code all appear as raw text.

Environment

• Tested on macOS Tahoe 26.4 (Terminal + iTerm2) and WSL2/Windows
• OpenCode versions tested: v1.3.0, v1.3.13, v1.3.17
• TERM=xterm-256color

What works

• OpenCode v1.2.0 (opentui 0.1.79) — markdown renders correctly

What doesn't work

• OpenCode v1.3.0+ (opentui 0.1.88+) — markdown is raw text
• Setting OPENCODE_EXPERIMENTAL_MARKDOWN=false does not fix it — the fallback <code filetype="markdown"> path is also broken with opentui 0.1.88+

Root cause analysis

The opentui upgrade from 0.1.79 → 0.1.88 (introduced in v1.3.0 via #18079) appears to have regressed both rendering paths:

• The new <markdown> component (default since v1.3.0)
• The old <code filetype="markdown"> fallback

Both worked with opentui 0.1.79 in v1.2.0.

Version comparison

OpenCode	opentui	Markdown flag default	Renders?
v1.2.0	0.1.79	opt-in (false)	✅ Yes
v1.3.0	0.1.88	opt-out (true)	❌ No
v1.3.13	0.1.95	opt-out (true)	❌ No
v1.3.17	0.1.96	opt-out (true)	❌ No

Relevant code

• packages/opencode/src/flag/flag.ts:70 — OPENCODE_EXPERIMENTAL_MARKDOWN changed from truthy() (opt-in) to !falsy() (opt-out)
• packages/opencode/src/cli/cmd/tui/routes/session/index.tsx — Both <markdown> and <code filetype="markdown"> paths affected
• Commit that upgraded opentui: 040f551 (Upgrade opentui to 0.1.88 #18079)

Plugins

None

OpenCode version

1.3.13 - 1.3.17

Steps to reproduce

1. Start OpenCode v1.3.0 or later
2. Ask any question that produces a markdown-formatted response
3. Headings, bold, code blocks render as raw plaintext

Screenshot and/or share link

No response

Operating System

Windows 11
MacOS
Linux Ubuntu 24.04

Terminal

Git Bash
Zsh
WSL2 Ubuntu

[kommander]

Could you share a screenshot and raw session data with /export where that happens?

[pahe-ppi]

Hi @kommander,
I'm not @ars-ppi, but a colleague with the same observations. Tables seem to work fine, but everything else is broken. Here you go:

session-ses_265c.md

[kommander]

That is very odd. Session looks normal. I cannot reproduce any issue. Are you sure that is on the latest version? cc @simonklee any ideas? We reverted the parser bundling issue, so that should be in. There are no parser logs for debugging anymore unfortunately.

[simonklee]

I have not seen this at all. But can investigate.

[pahe-ppi]

@kommander the linked session was created with v4.1.6, so not the latest latest, but almost.

[Mithras]

I'm having the same issue. I run opencode in a container:

FROM archlinux

RUN pacman -Sy --noconfirm --needed base-devel git curl ripgrep nodejs bun uv chromium

RUN mkdir -p /usr/local/bin/bun \
    && BUN_INSTALL=/usr/local/bin/bun bun i -g \
    opencode-ai@latest \
    oh-my-opencode-slim@latest \
    @tarquinen/opencode-dcp@latest \
    @th0rgal/ralph-wiggum@latest

ENV PATH="$PATH:/usr/local/bin/bun/bin"

ARG UNAME=opencode
ARG UID=1000
ARG GID=1000
RUN groupadd -g $GID $UNAME
RUN useradd -m -u $UID -g $GID $UNAME -G wheel \
    && passwd -d $UNAME \
    && echo "%wheel ALL=(ALL) ALL" >> /etc/sudoers.d/temp


USER $UNAME

WORKDIR /home/$UNAME

RUN mkdir -p ~/.config/opencode ~/.local/share/opencode ~/.local/state/opencode

# RUN git clone https://aur.archlinux.org/paru.git \
#     && cd paru \
#     && makepkg -si --noconfirm

# RUN sudo pacman -Sy --noconfirm opencode

RUN sudo rm /etc/sudoers.d/temp

ENV OPENCODE_ENABLE_EXA=1

ENV TERM=xterm-256color
ENV COLORTERM=truecolor
# ENV OTUI_TREE_SITTER_WORKER_PATH=/usr/local/bin/bun/install/global/node_modules/@opentui/core/parser.worker.js

ENTRYPOINT ["opencode"]

Tried arch package, bun install from root and bun install from user. All are the same: onyl tables are renderd properly, no other markdown works.