diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 15c2050a480fd..a3400aa8193e7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1011,6 +1011,54 @@ jobs:
         run: |
           (& ./uvx --generate-shell-completion powershell) | Out-String | Invoke-Expression
 
+  integration-test-nushell:
+    timeout-minutes: 10
+    needs: build-binary-linux-libc
+    name: "integration test | activate nushell venv"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          persist-credentials: false
+
+      - name: Install nushell
+        env:
+          # This token only needs read access to the GitHub repository nushell/nushell.
+          # This token is used (via gh-cli) to avoid hitting GitHub REST API rate limits.
+          GITHUB_TOKEN: ${{ github.token }}
+        run: |-
+          # get latest nushell tag name
+          nu_latest=$(gh release list --repo nushell/nushell --limit 1 --exclude-pre-releases --exclude-drafts --json "tagName" --jq '.[0].tagName')
+          # trim any trailing whitespace from output
+          nu_tag=${nu_latest%%[[:space:]]*}
+
+          # download binary for x86_64-unknown-linux-gnu target
+          gh release download ${nu_tag} --repo nushell/nushell --pattern "nu-${nu_tag}-x86_64-unknown-linux-gnu.tar.gz"
+
+          # extract nu binary from tar.gz
+          tar -xf "nu-${nu_tag}-x86_64-unknown-linux-gnu.tar.gz"
+          # make the binary executable
+          chmod +x "./nu-${nu_tag}-x86_64-unknown-linux-gnu/nu"
+          # add it to PATH
+          echo "${{ github.workspace }}/nu-${nu_tag}-x86_64-unknown-linux-gnu" >> "${GITHUB_PATH}"
+
+      - name: Download binary
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
+        with:
+          name: uv-linux-libc-${{ github.sha }}
+
+      - name: Prepare binary
+        run: chmod +x ./uv
+
+      - name: Create venv
+        # The python version is arbitrary for this test.
+        # We only want to ensure the activation script behaves properly
+        run: ./uv venv
+
+      - name: Activate venv
+        shell: nu {0}
+        run: overlay use ${{ github.workspace }}/.venv/bin/activate.nu
+
   integration-test-conda:
     timeout-minutes: 10
     needs: build-binary-linux-libc
diff --git a/crates/uv-virtualenv/README.md b/crates/uv-virtualenv/README.md
index 41ca24630b865..9573d7fa33c6f 100644
--- a/crates/uv-virtualenv/README.md
+++ b/crates/uv-virtualenv/README.md
@@ -1,3 +1,55 @@
 # uv-virtualenv
 
 `uv-virtualenv` is a rust library to create Python virtual environments. It also has a CLI.
+
+## Syncing with upstream virtualenv activation scripts
+
+This crate tries to stay in sync with pypa/virtualenv project's activation scrips. However, there
+are some deviations that are specific to this crate's implementation.
+
+### License disclaimers added
+
+This crate includes license information at the top of each activation script. This is done in
+accordance with the pypa/virtualenv project's MIT License. Do not remove the declarative license
+comments from this crate's activation scripts.
+
+### Placeholder names are slightly different
+
+Note, these activation scripts are actually templates that are populated with certain values when a
+virtual environment is created.
+
+In upstream, the placeholder names are found in
+[`virtualenv.activation.ViaTemplateActivator.replacements()`][upstream-placeholders].
+
+In this crate, the placeholder names are found in
+[`uv_virtualenv::virtualenv::create()`][crate-placeholders]
+
+[upstream-placeholders]:
+  https://github.com/pypa/virtualenv/blob/dad9369e97f5aef7e33777b18dcdb51b1fdac7bd/src/virtualenv/activation/via_template.py#L43
+[crate-placeholders]:
+  https://github.com/astral-sh/uv/blob/d8f3f03198308be53de51a3a297c85566eabb084/crates/uv-virtualenv/src/virtualenv.rs#L462
+
+It is important that the placeholder names (as used in the activation scripts) conform to the
+placeholders names used in [this crate's source][crate-placeholders].
+
+### Relocatable virtual environments
+
+This crate uses some additional tweaks in the activation scripts to ensure the virtual environment
+is relocatable. Thus, the patch in [astral-sh/uv#5640] shall be retained.
+
+[astral-sh/uv#5640]: https://github.com/astral-sh/uv/pull/5640
+
+### TCL/TK library locations
+
+The patches in upstream virtualenv ([pypa/virtualenv#2928] and [pypa/virtualenv#2940]) implement
+dynamically locating the TCL/TK libraries of a base Python distribution (see [upstream
+approach][upstream-tcl/tk-approach]).
+
+[pypa/virtualenv#2928]: https://github.com/pypa/virtualenv/pull/2928
+[pypa/virtualenv#2940]: https://github.com/pypa/virtualenv/pull/2940
+[upstream-tcl/tk-approach]:
+  https://github.com/pypa/virtualenv/blob/dad9369e97f5aef7e33777b18dcdb51b1fdac7bd/src/virtualenv/discovery/py_info.py#L140
+
+This upstream implementation is considered an undesirable complexity in this project. As such, the
+upstream TCL/TK related patches shall be omitted when syncing activation scripts with upstream
+sources.
diff --git a/crates/uv-virtualenv/src/activator/activate b/crates/uv-virtualenv/src/activator/activate
index 3c6b471b0e0d7..b1b115133624d 100644
--- a/crates/uv-virtualenv/src/activator/activate
+++ b/crates/uv-virtualenv/src/activator/activate
@@ -127,4 +127,4 @@ pydoc () {
 # The hash command must be called to get it to forget past
 # commands. Without forgetting past commands the $PATH changes
 # we made may not be respected
-hash -r 2>/dev/null
+hash -r 2>/dev/null || true
diff --git a/crates/uv-virtualenv/src/activator/activate.bat b/crates/uv-virtualenv/src/activator/activate.bat
index 90a15ec44798f..13c40ffbdaa91 100644
--- a/crates/uv-virtualenv/src/activator/activate.bat
+++ b/crates/uv-virtualenv/src/activator/activate.bat
@@ -21,8 +21,9 @@
 
 @REM This file is UTF-8 encoded, so we need to update the current code page while executing it
 @for /f "tokens=2 delims=:." %%a in ('"%SystemRoot%\System32\chcp.com"') do @set _OLD_CODEPAGE=%%a
+
 @if defined _OLD_CODEPAGE (
-    @"%SystemRoot%\System32\chcp.com" 65001 > nul
+    "%SystemRoot%\System32\chcp.com" 65001 > nul
 )
 
 @for %%i in ("{{ VIRTUAL_ENV_DIR }}") do @set "VIRTUAL_ENV=%%~fi"
@@ -64,8 +65,7 @@
 
 @set "PATH=%VIRTUAL_ENV%\{{ BIN_NAME }};%PATH%"
 
-:END
 @if defined _OLD_CODEPAGE (
-    @"%SystemRoot%\System32\chcp.com" %_OLD_CODEPAGE% > nul
+    "%SystemRoot%\System32\chcp.com" %_OLD_CODEPAGE% > nul
     @set _OLD_CODEPAGE=
 )
diff --git a/crates/uv-virtualenv/src/activator/activate.fish b/crates/uv-virtualenv/src/activator/activate.fish
index 423a86b5bce22..9968496dfc4c5 100644
--- a/crates/uv-virtualenv/src/activator/activate.fish
+++ b/crates/uv-virtualenv/src/activator/activate.fish
@@ -39,7 +39,7 @@ function deactivate -d 'Exit virtualenv mode and return to the normal environmen
     # reset old environment variables
     if test -n "$_OLD_VIRTUAL_PATH"
         # https://github.com/fish-shell/fish-shell/issues/436 altered PATH handling
-        if test (echo $FISH_VERSION | head -c 1) -lt 3
+        if test (string sub -s 1 -l 1 $FISH_VERSION) -lt 3
             set -gx PATH (_fishify_path "$_OLD_VIRTUAL_PATH")
         else
             set -gx PATH $_OLD_VIRTUAL_PATH
@@ -82,7 +82,7 @@ deactivate nondestructive
 set -gx VIRTUAL_ENV '{{ VIRTUAL_ENV_DIR }}'
 
 # https://github.com/fish-shell/fish-shell/issues/436 altered PATH handling
-if test (echo $FISH_VERSION | head -c 1) -lt 3
+if test (string sub -s 1 -l 1 $FISH_VERSION) -lt 3
     set -gx _OLD_VIRTUAL_PATH (_bashify_path $PATH)
 else
     set -gx _OLD_VIRTUAL_PATH $PATH
diff --git a/crates/uv-virtualenv/src/activator/activate.nu b/crates/uv-virtualenv/src/activator/activate.nu
index 6ee2c22716a74..a1306799499aa 100644
--- a/crates/uv-virtualenv/src/activator/activate.nu
+++ b/crates/uv-virtualenv/src/activator/activate.nu
@@ -19,97 +19,82 @@
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-# virtualenv activation module
-# Activate with `overlay use activate.nu`
-# Deactivate with `deactivate`, as usual
+# virtualenv activation module:
+# - Activate with `overlay use activate.nu`
+# - Deactivate with `deactivate`, as usual
 #
-# To customize the overlay name, you can call `overlay use activate.nu as foo`,
-# but then simply `deactivate` won't work because it is just an alias to hide
-# the "activate" overlay. You'd need to call `overlay hide foo` manually.
+# To customize the overlay name, you can call `overlay use activate.nu as foo`, but then simply `deactivate` won't work
+# because it is just an alias to hide the "activate" overlay. You'd need to call `overlay hide foo` manually.
+
+module warning {
+    export-env {
+        const file = path self
+        error make -u {
+            msg: $"`($file | path basename)` is meant to be used with `overlay use`, not `source`"
+        }
+    }
+
+}
+
+use warning
 
 export-env {
+
+    let nu_ver = (version | get version | split row '.' | take 2 | each { into int })
+        if $nu_ver.0 == 0 and $nu_ver.1 < 106 {
+            error make {
+                msg: 'virtualenv Nushell activation requires Nushell 0.106 or greater.'
+            }
+    }
+
     def is-string [x] {
         ($x | describe) == 'string'
     }
 
     def has-env [...names] {
-        $names | each {|n|
-            $n in $env
-        } | all {|i| $i == true}
+        $names | each {|n| $n in $env } | all {|i| $i }
     }
 
-    # Emulates a `test -z`, but better as it handles e.g 'false'
     def is-env-true [name: string] {
-      if (has-env $name) {
-        # Try to parse 'true', '0', '1', and fail if not convertible
-        let parsed = (do -i { $env | get $name | into bool })
-        if ($parsed | describe) == 'bool' {
-          $parsed
+        if (has-env $name) {
+            let val = ($env | get --optional $name)
+            if ($val | describe) == 'bool' {
+                $val
+            } else {
+                not ($val | is-empty)
+            }
         } else {
-          not ($env | get -i $name | is-empty)
+            false
         }
-      } else {
-        false
-      }
     }
 
     let virtual_env = '{{ VIRTUAL_ENV_DIR }}'
     let bin = '{{ BIN_NAME }}'
-
-    let is_windows = ($nu.os-info.family) == 'windows'
-    let path_name = (if (has-env 'Path') {
-            'Path'
-        } else {
-            'PATH'
-        }
-    )
-
+    let path_name = if (has-env 'Path') { 'Path' } else { 'PATH' }
     let venv_path = ([$virtual_env $bin] | path join)
     let new_path = ($env | get $path_name | prepend $venv_path)
-
-    # If there is no default prompt, then use the env name instead
-    let virtual_env_prompt = (if ('{{ VIRTUAL_PROMPT }}' | is-empty) {
+    let virtual_env_prompt = if ('{{ VIRTUAL_PROMPT }}' | is-empty) {
         ($virtual_env | path basename)
     } else {
         '{{ VIRTUAL_PROMPT }}'
-    })
-
-    let new_env = {
-        $path_name         : $new_path
-        VIRTUAL_ENV        : $virtual_env
-        VIRTUAL_ENV_PROMPT : $virtual_env_prompt
     }
-
-    let new_env = (if (is-env-true 'VIRTUAL_ENV_DISABLE_PROMPT') {
-      $new_env
+    let new_env = { $path_name: $new_path VIRTUAL_ENV: $virtual_env VIRTUAL_ENV_PROMPT: $virtual_env_prompt }
+    let old_prompt_command = if (has-env 'PROMPT_COMMAND') { $env.PROMPT_COMMAND } else { '' }
+    let new_env = if (is-env-true 'VIRTUAL_ENV_DISABLE_PROMPT') {
+        $new_env
     } else {
-      # Creating the new prompt for the session
-      let virtual_prefix = $'(char lparen)($virtual_env_prompt)(char rparen) '
-
-      # Back up the old prompt builder
-      let old_prompt_command = (if (has-env 'PROMPT_COMMAND') {
-              $env.PROMPT_COMMAND
-          } else {
-              ''
-        })
-
-      let new_prompt = (if (has-env 'PROMPT_COMMAND') {
-          if 'closure' in ($old_prompt_command | describe) {
-              {|| $'($virtual_prefix)(do $old_prompt_command)' }
-          } else {
-              {|| $'($virtual_prefix)($old_prompt_command)' }
-          }
-      } else {
-          {|| $'($virtual_prefix)' }
-      })
-
-      $new_env | merge {
-        PROMPT_COMMAND      : $new_prompt
-        VIRTUAL_PREFIX      : $virtual_prefix
-      }
-    })
-
-    # Environment variables that will be loaded as the virtual env
+        let virtual_prefix = $'(char lparen)($virtual_env_prompt)(char rparen) '
+        let new_prompt = if (has-env 'PROMPT_COMMAND') {
+            if ('closure' in ($old_prompt_command | describe)) {
+                {|| $'($virtual_prefix)(do $old_prompt_command)' }
+            } else {
+                {|| $'($virtual_prefix)($old_prompt_command)' }
+            }
+        } else {
+            {|| $'($virtual_prefix)' }
+        }
+        $new_env | merge { PROMPT_COMMAND: $new_prompt VIRTUAL_PREFIX: $virtual_prefix }
+    }
     load-env $new_env
 }
 
diff --git a/crates/uv-virtualenv/src/activator/deactivate.bat b/crates/uv-virtualenv/src/activator/deactivate.bat
index 95af1351b0c96..78ed412d6a782 100644
--- a/crates/uv-virtualenv/src/activator/deactivate.bat
+++ b/crates/uv-virtualenv/src/activator/deactivate.bat
@@ -36,4 +36,4 @@
 @if not defined _OLD_VIRTUAL_PATH @goto ENDIFVPATH
     @set "PATH=%_OLD_VIRTUAL_PATH%"
     @set _OLD_VIRTUAL_PATH=
-:ENDIFVPATH
\ No newline at end of file
+:ENDIFVPATH
diff --git a/crates/uv-virtualenv/src/activator/pydoc.bat b/crates/uv-virtualenv/src/activator/pydoc.bat
index 8a8d590d22a32..fe756863e419b 100644
--- a/crates/uv-virtualenv/src/activator/pydoc.bat
+++ b/crates/uv-virtualenv/src/activator/pydoc.bat
@@ -19,4 +19,4 @@
 @REM OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 @REM WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-python.exe -m pydoc %*
\ No newline at end of file
+python.exe -m pydoc %*