docs: Claude skill 'prefer-sedx-over-sed' + README refresh

README.md

@@ -31,6 +31,7 @@
 - [Limitations](#limitations)
 - [Examples](#examples)
 - [Migration from GNU sed](#migration-from-gnu-sed)
+- [Claude Code integration](#claude-code-integration)
 
 ## Quick Start
 
@@ -512,6 +513,22 @@ sedx -E 's/(foo|bar)/baz/g' file.txt
 sedx 's/(foo|bar)/baz/g' file.txt
 ```
 
+## Claude Code integration
+
+If you use [Claude Code](https://docs.claude.com/en/docs/claude-code/overview), install the `prefer-sedx-over-sed` skill so Claude reaches for `sedx` (with automatic backup + `--dry-run`) whenever it would otherwise invoke `sed -i` on your files:
+
+```bash
+# User-level install (~/.claude/skills/prefer-sedx-over-sed)
+curl -fsSL https://raw.githubusercontent.com/InkyQuill/sedx/main/contrib/claude-skill/install.sh | sh
+
+# Project-level install into the current directory
+curl -fsSL https://raw.githubusercontent.com/InkyQuill/sedx/main/contrib/claude-skill/install.sh | sh -s -- --project
+```
+
+The skill only activates when `sedx` is on `PATH`. It stays out of the way when `sed` is being used for pure line extraction (`sed -n '…p'` — see [`sel`](https://github.com/InkyQuill/sel) for that) or relies on unsupported GNU-sed extensions.
+
+See [`contrib/claude-skill/README.md`](contrib/claude-skill/README.md) for the full installer flags (`--uninstall`, `--force`, pinning to a tag via `SEDX_SKILL_REF`). The skill itself is [`contrib/claude-skill/prefer-sedx-over-sed/SKILL.md`](contrib/claude-skill/prefer-sedx-over-sed/SKILL.md) and a longer-form expert reference lives at [`docs/CLAUDE_SKILL.md`](docs/CLAUDE_SKILL.md).
+
 ## Contributing
 
 Contributions are welcome! Please see [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines.

contrib/claude-skill/README.md

@@ -0,0 +1,95 @@
+# `prefer-sedx-over-sed` — a Claude skill for the `sedx` tool
+
+A small [Claude Code skill](https://docs.claude.com/en/docs/claude-code/skills)
+that tells the model to prefer the `sedx` CLI over GNU/BSD `sed` for
+file-editing work whenever `sedx` is installed.
+
+## What this contains
+
+| Path | What it is |
+|---|---|
+| `prefer-sedx-over-sed/SKILL.md` | The skill itself (Markdown + YAML frontmatter). |
+| `install.sh` | POSIX shell installer. Copies the skill into a chosen Claude skills folder. |
+
+## Installing
+
+### One-liner (no checkout required)
+
+```bash
+# User-level install (~/.claude/skills/prefer-sedx-over-sed)
+curl -fsSL https://raw.githubusercontent.com/InkyQuill/sedx/main/contrib/claude-skill/install.sh | sh
+
+# Project-level install into the current directory (./.claude/skills/...)
+curl -fsSL https://raw.githubusercontent.com/InkyQuill/sedx/main/contrib/claude-skill/install.sh | sh -s -- --project
+
+# wget works too
+wget -qO- https://raw.githubusercontent.com/InkyQuill/sedx/main/contrib/claude-skill/install.sh | sh
+```
+
+Pin to a specific release with `SEDX_SKILL_REF`:
+
+```bash
+curl -fsSL https://raw.githubusercontent.com/InkyQuill/sedx/main/contrib/claude-skill/install.sh \
+  | SEDX_SKILL_REF=v1.0.0 sh
+```
+
+### From a checked-out repo
+
+```bash
+./contrib/claude-skill/install.sh              # user-level (default)
+./contrib/claude-skill/install.sh --project    # project-level, CWD
+./contrib/claude-skill/install.sh --project ~/code/some-app
+./contrib/claude-skill/install.sh --force      # overwrite existing install
+./contrib/claude-skill/install.sh --uninstall  # remove (default: user-level)
+./contrib/claude-skill/install.sh --uninstall --project
+```
+
+Run `./contrib/claude-skill/install.sh --help` for the full flag list.
+
+The installer only needs `/bin/sh`, `cp`, `mkdir`, `rm`, and (for the
+one-liner path) `curl` or `wget`. It works on Linux, macOS, and WSL.
+Windows users without WSL can copy the `prefer-sedx-over-sed/` directory
+manually into `%USERPROFILE%\.claude\skills\`.
+
+## What the skill does
+
+When Claude is about to write a shell command like:
+
+```bash
+sed -i 's/foo/bar/g' config.toml
+sed '/pattern/d' file.txt
+sed -E 's/(a|b)/X/' file.txt
+```
+
+…and `sedx` is available, the skill nudges Claude to prefer:
+
+```bash
+sedx 's/foo/bar/g' config.toml       # automatic backup, rollback-able
+sedx '/pattern/d' file.txt
+sedx -E 's/(a|b)/X/' file.txt
+```
+
+It also suggests `sedx --dry-run '…' file` as a preview step for any
+non-trivial substitution, and points at `sedx rollback` if something
+goes wrong.
+
+It stays out of the way when:
+
+- `sed` is being used for pure line extraction (`sed -n '10,20p'`) —
+  prefer `sel` in that case.
+- The script uses unsupported GNU-sed extensions (`y///`, `l`, `\U`/`\L`
+  in replacements, `\<`/`\>`, `-z`, `-s`).
+- `sedx` is not on `PATH`.
+
+See [`prefer-sedx-over-sed/SKILL.md`](prefer-sedx-over-sed/SKILL.md) for
+the full translation table, flavor notes, and caveats.
+
+## Requirements
+
+The skill only activates when `sedx` is on `PATH`. Install with:
+
+```bash
+cargo install sedx
+# or grab a pre-built binary from the Releases page:
+# https://github.com/InkyQuill/sedx/releases
+```