Auto-linker wraps filenames as URLs (e.g. `CLAUDE.md` → `[CLAUDE.md](http://CLAUDE.md)`)

Summary

The implicit auto-linker in Claude Code's chat rendering treats any token matching word.tld-style patterns as a URL and wraps it in a markdown link to http://<token>. In practice this fires far more often on filenames in prose than on actual bare URLs, producing dead/incorrect links the vast majority of the time.

Repro

Send (or have the model emit) a message containing a bare filename in prose, e.g.:

Just write CLAUDE.md as plain text.

Rendered output:

Just write CLAUDE.md as plain text.

The same happens with package.json, tsconfig.json, Program.cs, appsettings.json, Cargo.toml, etc. — the link target http://CLAUDE.md (or http://package.json, etc.) is not a real URL and resolves to nothing.

This also corrupts copy/paste round-trips: when a user copies the rendered text and pastes it back into chat (or into another tool), the markdown-link form is preserved, so future messages now contain [CLAUDE.md](http://CLAUDE.md) instead of the original CLAUDE.md. The artifact then propagates.

Why this is a regression

Before the auto-linker, filenames in prose rendered as plain inline code or plain text — correct. The new behavior:

• False positives dominate. Filenames-in-prose are vastly more common in dev workflows than bare unlinked domains. The heuristic is wrong by default.
• True positives are trivially user-fixable. If someone genuinely wants example.com to be clickable, they can write [example.com](https://example.com) or <https://example.com>. The implicit case is the lossy one.
• Already-formatted links survive. Users and the model both already use explicit [text](url) markdown when a real link is intended. The implicit wrapper adds noise without solving an unmet need.
• It mangles model-generated file references too. When the assistant mentions CLAUDE.md or tsconfig.json in a response, the rendering layer converts those to broken http:// links — which then look like the assistant did something wrong.

Requested change

At minimum, make implicit auto-linking opt-in via settings (default off), or restrict the heuristic to tokens that look like real domains (require a known TLD AND no path-style filename extension like .md/.json/.cs/.ts/.py/.toml/.yaml/.yml/.lock/.config).

Removing the auto-linker entirely is also reasonable — explicit markdown link syntax already covers the legitimate case.

Environment

• Claude Code 2.1.119
• Windows 11 Pro