Problem

Long URLs containing / and - characters are split across multiple terminal lines by textwrap's default hyphenation rules. This breaks terminal link detection: emulators can no longer identify the URL as clickable, and copy-paste yields a truncated fragment. The issue affects every view that renders user or agent text — exec output, history cells, markdown, the app-link setup screen, and the VT100 scrollback path.

A secondary bug compounds the first: desired_height() calculations count logical lines rather than viewport rows. When a URL overflows its line and wraps visually, the height budget is too small, causing content to clip or leave gaps.

Here is how the complete URL is interpreted by the terminal before (first line only) and after (complete URL):

Before	After

Mental model

The TUI now treats URL-like tokens as atomic units that must never be split by the wrapping engine. Every call site that previously used word_wrap_* has been migrated to adaptive_wrap_*, which inspects each line for URL-like tokens and switches wrapping strategy accordingly:

• Non-URL lines follow the existing textwrap path unchanged (word boundaries, optional indentation, hyphenation).
• URL-only lines (with at most decorative markers like │, -, 1.) are emitted unwrapped so terminal link detection works; ratatui's Wrap { trim: false } handles the final character wrap at render time.
• Mixed lines (URL + substantive non-URL prose) flow through adaptive_wrap_line so prose wraps naturally at word boundaries while URL tokens remain unsplit.

Height measurement everywhere now delegates to Paragraph::line_count(width), which accounts for the visual row cost of overflowed lines. This single source of truth replaces ad-hoc line counting in individual cells.

For terminal scrollback (the VT100 path that prints history when the TUI exits), URL-only lines are emitted unwrapped so the terminal's own link detector can find them. Mixed URL+prose lines use adaptive wrapping so surrounding text wraps naturally. Continuation rows are pre-cleared to avoid stale content artifacts.

Non-goals

• Full RFC 3986 URL parsing. The detector is a conservative heuristic that covers scheme://host, bare domains (example.com/path), localhost:port, and IPv4 hosts. IPv6 ([::1]:8080) and exotic schemes are intentionally excluded from v1.
• Changing wrapping behavior for non-URL content.
• Reflowing or reformatting existing terminal scrollback on resize.

Tradeoffs

Architecture

flowchart TD
    A["adaptive_wrap_*()"] --> B{"line_contains_url_like?"}
    B -- No URL tokens --> C["word_wrap_line<br/>(textwrap default)"]
    B -- Has URL tokens --> D{"mixed URL + prose?"}
    D -- "URL-only<br/>(+ decorative markers)" --> E["emit unwrapped<br/>(terminal char-wraps)"]
    D -- "Mixed<br/>(URL + substantive text)" --> F["adaptive_wrap_line<br/>(AsciiSpace + custom WordSplitter)"]
    C --> G["Paragraph::line_count(w)<br/>(single height truth)"]
    E --> G
    F --> G

Changed files:

Observability

• Ellipsis message in truncated exec output reports omitted count in logical lines (stable across resize) rather than viewport rows (fluctuates).
• URL detection is deterministic and stateless — no hidden caching or memoization to go stale.
• Height mismatch bugs surface immediately as visual clipping or gaps; the Paragraph::line_count path is the same code ratatui uses at render time, so measurement and rendering cannot diverge.

Tests

26 new unit tests across 7 files, covering:

• URL integrity: assert a URL-like token appears on exactly one rendered line (not split across two).
• Height accuracy: compare desired_height() against Paragraph::line_count() for URL-containing content.
• Row-aware truncation: verify ellipsis counts logical lines and output fits within the row budget.
• Scrollback rendering: VT100 backend tests confirm prefix and URL land on the same row; continuation rows are cleared; mixed URL+prose lines wrap prose while preserving URL tokens.
• Mixed URL+prose detection: line_has_mixed_url_and_non_url_tokens correctly distinguishes lines with substantive non-URL text from lines with only decorative markers alongside a URL.
• Heuristic correctness: positive matches (https://..., example.com/path, localhost:3000/api, 192.168.1.1:8080/health) and negative matches (src/main.rs, foo/bar, hello-world).

Risks and open items

1. URL-like tokens in code output (e.g. example.com/api inside a JSON blob) will trigger URL-preserving wrap on that line. This is acceptable — the worst case is a slightly wider line, not broken output.
2. Very long non-URL tokens on a URL line can only break at character boundaries (the custom splitter emits all char indices for non-URL words). On extremely narrow terminals this could overflow, but narrow terminals already degrade gracefully.
3. No IPv6 support — [::1]:8080/path will be treated as a non-URL and may get split. Can be added later without API changes.

Fixes #5457