## Why
The TUI currently treats Markdown tables as ordinary wrapped text, which
makes table-heavy responses hard to read and brittle across narrow panes
and terminal resizes.
This change teaches the TUI to render Markdown tables responsively while
preserving the raw Markdown source needed to re-render streamed and
finalized transcript content after width changes. The goal is to keep
tables legible during streaming, after resize, and once a turn has
finished, without corrupting scrollback ordering.
## What Changed
- add table detection and responsive table rendering in the Markdown
renderer
- render standard tables with Unicode box-drawing borders when the pane
is wide enough
- add a vertical readability fallback for constrained or dense tables so
narrow panes still show each row clearly
- keep links and `<br>` content inside table cells instead of leaking
text outside the table
- avoid table normalization inside fenced or indented code blocks
- preserve raw streamed Markdown source and keep the active table as a
mutable tail until finalization
- consolidate finalized streamed content into source-backed transcript
cells so post-resize re-rendering stays correct
- add snapshot and targeted streaming/resize regression coverage for the
new table behavior
## How to Test
1. Start Codex TUI from this branch.
2. Paste this exact prompt:
`This is a session to test codex, no need to do any thinking, just end
different markdown tables, with columns exploring different markdown
contents, like links, bold italic, code, etc. Make them different sizes,
some 30+ rows, some not and intertwine them with some paragraphs with
complex formatting as well.`
3. Confirm the response includes several Markdown tables mixed with
richly formatted paragraphs.
4. Confirm wide-enough tables render with box-drawing borders instead of
plain wrapped pipe text.
5. Resize the terminal narrower while the answer is still streaming and
confirm the in-progress table stays coherent instead of duplicating
headers or leaving broken scrollback behind.
6. Resize again after the turn finishes and confirm the finalized
transcript re-renders cleanly at the new width.
7. In a narrow pane, verify dense tables fall back to the vertical
per-row layout instead of producing unreadable wrapped columns.
8. Also verify pipe-heavy fenced code blocks still render as code, not
as tables.
Targeted tests:
- `cargo test -p codex-tui table_readability_fallback --no-fail-fast`
- `cargo test -p codex-tui markdown_render --no-fail-fast`
- `cargo test -p codex-tui streaming::controller --no-fail-fast`
- `cargo test -p codex-tui table_resize_lifecycle --no-fail-fast`
## Docs
No developer docs update appears necessary.
## Why
Mixed prose lines that contained URLs started taking the URL-preserving
wrapping path, but that path could split ordinary words mid-token. A
follow-up issue remained in scrollback insertion: when already-rendered
indented rows were wrapped again, continuation rows could lose their
margin and fall back to terminal hard wrapping. Together those bugs made
normal Markdown output look broken around links, lists, blockquotes, and
indented content.
Separately, the local argument-comment lint wrappers failed under
environments that set `PYTHONSAFEPATH=1`, because Python no longer adds
the script directory to `sys.path` automatically. That prevented the
lint from reaching Rust callsites at all.
<img width="1778" height="1558" alt="CleanShot 2026-05-09 at 11 51 38"
src="https://github.com/user-attachments/assets/9274d150-1757-4f1a-89ac-5bdc9997d8cb"
/>
## What Changed
- Preserve URL tokens without turning every neighboring prose word into
a character-level split point.
- Add a mixed URL/prose wrapper that keeps ordinary words whole,
preserves leading whitespace, and re-splits long non-URL tokens against
the actual width available on continuation rows.
- Reuse a rendered history row's leading whitespace as the continuation
indent when scrollback insertion has to pre-wrap it again.
- Add regression coverage for markdown wrapping, history-cell rendering,
scrollback continuation margins, leading-indent width accounting, and
continuation-row re-splitting.
- Make both argument-comment lint entrypoints explicitly add their own
directory to `sys.path`, so sibling imports still work when
`PYTHONSAFEPATH=1`.
## How to Test
1. Start Codex and render a long Markdown response that mixes prose with
inline links, blockquotes, lists, and indented code-like text.
2. Confirm that ordinary words next to links stay whole instead of
breaking mid-word.
3. Resize or replay the transcript and confirm wrapped continuation rows
keep their expected left margin for blockquotes, lists, and indented
content.
4. Run the source argument-comment lint from a shell with
`PYTHONSAFEPATH=1` and confirm it starts normally instead of failing to
import `wrapper_common`.
Targeted tests:
- `cargo test -p codex-tui mixed_line --lib`
- `cargo test -p codex-tui preserves_prefix_on_wrapped_rows --lib`
- `cargo test -p codex-tui
agent_markdown_cell_does_not_split_words_after_inline_markdown --lib`
- `cargo test -p codex-tui
mixed_url_markdown_wraps_prose_without_splitting_words_snapshot --lib`
- `python3 tools/argument-comment-lint/test_wrapper_common.py`
- `just argument-comment-lint-from-source -p codex-tui -- --lib`
Notes:
- `cargo test -p codex-tui` currently reaches the new tests
successfully, then still aborts in the pre-existing
`tests::fork_last_filters_latest_session_by_cwd_unless_show_all`
stack-overflow failure.
## Why
Fixes#19702.
The TUI markdown renderer could visually attach the next list marker to
a fenced code block inside the previous list item, even when the source
markdown included a blank line before the next item. That made
block-heavy loose lists harder to read, while the desired behavior is
still to keep simple lists compact.
## What changed
- Track whether the current rendered list item contains a code block.
- Preserve one blank separator before the following list marker only
when the previous item contained a code block.
- Add regression coverage for both paths: code-block list items keep the
separator, and simple loose list items stay compact.
## Verification
- `cargo test -p codex-tui markdown_render`
I also manually verified that the bug exists before and is fixed after.
## Before
<img width="437" height="240" alt="Screenshot 2026-04-26 at 1 19 01 PM"
src="https://github.com/user-attachments/assets/3bc9d64d-2dba-40d9-9d6b-a1d0b3c0f728"
/>
## After
<img width="410" height="269" alt="Screenshot 2026-04-26 at 1 18 54 PM"
src="https://github.com/user-attachments/assets/19c15bee-da32-455e-a7cb-e05eb85f4ea0"
/>
Addresses #16622
Problem: bare local file links in TUI markdown render percent-encoded
path bytes literally, unlike file:// links.
Solution: decode bare path targets before local-path expansion and add
regression coverage for spaces and Unicode.
This is a follow-up to https://github.com/openai/codex/pull/15922. That
previous PR deleted the old `tui` directory and left the new
`tui_app_server` directory in place. This PR renames `tui_app_server` to
`tui` and fixes up all references.
This is the part 1 of 2 PRs that will delete the `tui` /
`tui_app_server` split. This part simply deletes the existing `tui`
directory and marks the `tui_app_server` feature flag as removed. I left
the `tui_app_server` feature flag in place for now so its presence
doesn't result in an error. It is simply ignored.
Part 2 will rename the `tui_app_server` directory `tui`. I did this as
two parts to reduce visible code churn.
we recently changed file linking so the model uses markdown links when
it wants something to be clickable.
This works well across the GUI surfaces because they can render markdown
cleanly and use the full absolute path in the anchor target.
A previous pass hid the absolute path in the TUI (and only showed the
label), but that also meant we could lose useful location info when the
model put the line number or range in the anchor target instead of the
label.
This follow-up keeps the TUI behavior simple while making local file
links feel closer to the old TUI file reference style.
key changes:
- Local markdown file links in the TUI keep the old file-ref feel: code
styling, no underline, no visible absolute path.
- If the hidden local anchor target includes a location suffix and the
label does not already include one, we append that suffix to the visible
label.
- This works for single lines, line/column references, and ranges.
- If the label already includes the location, we leave it alone.
- normal web links keep the old TUI markdown-link behavior
some examples:
- `[foo.rs](/abs/path/foo.rs)` renders as `foo.rs`
- `[foo.rs](/abs/path/foo.rs:45)` renders as `foo.rs:45`
- `[foo.rs](/abs/path/foo.rs:45:3-48:9)` renders as `foo.rs:45:3-48:9`
- `[foo.rs:45](/abs/path/foo.rs:45)` stays `foo.rs:45`
- `[docs](https://example.com/docs)` still renders like a normal web
link
how it looks:
<img width="732" height="813" alt="Screenshot 2026-02-26 at 9 27 55 AM"
src="https://github.com/user-attachments/assets/d51bf236-653a-4e83-96e4-9427f0804471"
/>
## Summary
- hide appended destinations for local path-style markdown links in the
TUI renderer
- keep web links rendering with their visible destination and style link
labels consistently
- add markdown renderer tests and a snapshot for the new file-link
output
## Testing
- just fmt
- cargo test -p codex-tui
<img width="1120" height="968" alt="image"
src="https://github.com/user-attachments/assets/490e8eda-ae47-4231-89fa-b254a1f83eed"
/>
## Summary
Adds syntax highlighting to the TUI for fenced code blocks in markdown
responses and file diffs, plus a `/theme` command with live preview and
persistent theme selection. Uses syntect (~250 grammars, 32 bundled
themes, ~1 MB binary cost) — the same engine behind `bat`, `delta`, and
`xi-editor`. Includes guardrails for large inputs, graceful fallback to
plain text, and SSH-aware clipboard integration for the `/copy` command.
<img width="1554" height="1014" alt="image"
src="https://github.com/user-attachments/assets/38737a79-8717-4715-b857-94cf1ba59b85"
/>
<img width="2354" height="1374" alt="image"
src="https://github.com/user-attachments/assets/25d30a00-c487-4af8-9cb6-63b0695a4be7"
/>
## Problem
Code blocks in the TUI (markdown responses and file diffs) render
without syntax highlighting, making it hard to scan code at a glance.
Users also have no way to pick a color theme that matches their terminal
aesthetic.
## Mental model
The highlighting system has three layers:
1. **Syntax engine** (`render::highlight`) -- a thin wrapper around
syntect + two-face. It owns a process-global `SyntaxSet` (~250 grammars)
and a `RwLock<Theme>` that can be swapped at runtime. All public entry
points accept `(code, lang)` and return ratatui `Span`/`Line` vectors or
`None` when the language is unrecognized or the input exceeds safety
guardrails.
2. **Rendering consumers** -- `markdown_render` feeds fenced code blocks
through the engine; `diff_render` highlights Add/Delete content as a
whole file and Update hunks per-hunk (preserving parser state across
hunk lines). Both callers fall back to plain unstyled text when the
engine returns `None`.
3. **Theme lifecycle** -- at startup the config's `tui.theme` is
resolved to a syntect `Theme` via `set_theme_override`. At runtime the
`/theme` picker calls `set_syntax_theme` to swap themes live; on cancel
it restores the snapshot taken at open. On confirm it persists `[tui]
theme = "..."` to config.toml.
## Non-goals
- Inline diff highlighting (word-level change detection within a line).
- Semantic / LSP-backed highlighting.
- Theme authoring tooling; users supply standard `.tmTheme` files.
## Tradeoffs
| Decision | Upside | Downside |
| ------------------------------------------------ |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
-----------------------------------------------------------------------------------------------------------------------
|
| syntect over tree-sitter / arborium | ~1 MB binary increase for ~250
grammars + 32 themes; battle-tested crate powering widely-used tools
(`bat`, `delta`, `xi-editor`). tree-sitter would add ~12 MB for 20-30
languages or ~35 MB for full coverage. | Regex-based; less structurally
accurate than tree-sitter for some languages (e.g. language injections
like JS-in-HTML). |
| Global `RwLock<Theme>` | Enables live `/theme` preview without
threading Theme through every call site | Lock contention risk
(mitigated: reads vastly outnumber writes, single UI thread) |
| Skip background / italic / underline from themes | Terminal BG
preserved, avoids ugly rendering on some themes | Themes that rely on
these properties lose fidelity |
| Guardrails: 512 KB / 10k lines | Prevents pathological stalls on huge
diffs or pastes | Very large files render without color |
## Architecture
```
config.toml ─[tui.theme]─> set_theme_override() ─> THEME (RwLock)
│
┌───────────────────────────────────────────┘
│
markdown_render ─── highlight_code_to_lines(code, lang) ─> Vec<Line>
diff_render ─── highlight_code_to_styled_spans(code, lang) ─> Option<Vec<Vec<Span>>>
│
│ (None ⇒ plain text fallback)
│
/theme picker ─── set_syntax_theme(theme) // live preview swap
─── current_syntax_theme() // snapshot for cancel
─── resolve_theme_by_name(name) // lookup by kebab-case
```
Key files:
- `tui/src/render/highlight.rs` -- engine, theme management, guardrails
- `tui/src/diff_render.rs` -- syntax-aware diff line wrapping
- `tui/src/theme_picker.rs` -- `/theme` command builder
- `tui/src/bottom_pane/list_selection_view.rs` -- side content panel,
callbacks
- `core/src/config/types.rs` -- `Tui::theme` field
- `core/src/config/edit.rs` -- `syntax_theme_edit()` helper
## Observability
- `tracing::warn` when a configured theme name cannot be resolved.
- `Config::startup_warnings` surfaces the same message as a TUI banner.
- `tracing::error` when persisting theme selection fails.
## Tests
- Unit tests in `highlight.rs`: language coverage, fallback behavior,
CRLF stripping, style conversion, guardrail enforcement, theme name
mapping exhaustiveness.
- Unit tests in `diff_render.rs`: snapshot gallery at multiple terminal
sizes (80x24, 94x35, 120x40), syntax-highlighted wrapping, large-diff
guardrail, rename-to-different-extension highlighting, parser state
preservation across hunk lines.
- Unit tests in `theme_picker.rs`: preview rendering (wide + narrow),
dim overlay on deletions, subtitle truncation, cancel-restore, fallback
for unavailable configured theme.
- Unit tests in `list_selection_view.rs`: side layout geometry, stacked
fallback, buffer clearing, cancel/selection-changed callbacks.
- Integration test in `lib.rs`: theme warning uses the final
(post-resume) config.
## Cargo Deny: Unmaintained Dependency Exceptions
This PR adds two `cargo deny` advisory exceptions for transitive
dependencies pulled in by `syntect v5.3.0`:
| Advisory | Crate | Status |
|----------|-------|--------|
| RUSTSEC-2024-0320 | `yaml-rust` | Unmaintained (maintainer
unreachable) |
| RUSTSEC-2025-0141 | `bincode` | Unmaintained (development ceased;
v1.3.3 considered complete) |
**Why this is safe in our usage:**
- Neither advisory describes a known security vulnerability. Both are
"unmaintained" notices only.
- `bincode` is used by syntect to deserialize pre-compiled syntax sets.
Again, these are **static vendored artifacts** baked into the binary at
build time. No user-supplied bincode data is ever deserialized. - Attack
surface is zero for both crates; exploitation would require a
supply-chain compromise of our own build artifacts.
- These exceptions can be removed when syntect migrates to `yaml-rust2`
and drops `bincode`, or when alternative crates are available upstream.
Also, simplify the streaming behavior.
This fixes a number of display issues with streaming markdown, and paves
the way for better markdown features (e.g. customizable styles, syntax
highlighting, markdown-aware wrapping).
Not currently supported:
- footnotes
- tables
- reference-style links
