feat(prepare): add mise prepare command for dependency preparation

docs/.vitepress/cli_commands.ts

@@ -210,6 +210,9 @@ export const commands: { [key: string]: Command } = {
       },
     },
   },
+  prepare: {
+    hide: false,
+  },
   prune: {
     hide: false,
   },

docs/.vitepress/config.ts

@@ -67,6 +67,7 @@ export default withMermaid(
             { text: "Tool Stubs", link: "/dev-tools/tool-stubs" },
             { text: "Registry", link: "/registry" },
             { text: "mise.lock Lockfile", link: "/dev-tools/mise-lock" },
+            { text: "Prepare", link: "/dev-tools/prepare" },
             {
               text: "Backend Architecture",
               link: "/dev-tools/backend_architecture",

docs/cli/exec.md

@@ -36,6 +36,10 @@ Command string to execute
 Number of jobs to run in parallel
 [default: 4]
 
+### `--no-prepare`
+
+Skip automatic dependency preparation
+
 ### `--raw`
 
 Directly pipe stdin/stdout/stderr from plugin to user Sets --jobs=1

docs/cli/index.md

@@ -119,6 +119,7 @@ Can also use `MISE_NO_CONFIG=1`
 - [`mise plugins ls-remote [-u --urls] [--only-names]`](/cli/plugins/ls-remote.md)
 - [`mise plugins uninstall [-a --all] [-p --purge] [PLUGIN]…`](/cli/plugins/uninstall.md)
 - [`mise plugins update [-j --jobs <JOBS>] [PLUGIN]…`](/cli/plugins/update.md)
+- [`mise prepare [FLAGS]`](/cli/prepare.md)
 - [`mise prune [FLAGS] [INSTALLED_TOOL]…`](/cli/prune.md)
 - [`mise registry [FLAGS] [NAME]`](/cli/registry.md)
 - [`mise reshim [-f --force]`](/cli/reshim.md)

docs/cli/prepare.md

@@ -0,0 +1,71 @@
+<!-- @generated by usage-cli from usage spec -->
+# `mise prepare`
+
+- **Usage**: `mise prepare [FLAGS]`
+- **Aliases**: `prep`
+- **Source code**: [`src/cli/prepare.rs`](https://github.com/jdx/mise/blob/main/src/cli/prepare.rs)
+
+[experimental] Ensure project dependencies are ready
+
+Runs all applicable prepare steps for the current project.
+This checks if dependency lockfiles are newer than installed outputs
+(e.g., package-lock.json vs node_modules/) and runs install commands
+if needed.
+
+Providers with `auto = true` are automatically invoked before `mise x` and `mise run`
+unless skipped with the --no-prepare flag.
+
+## Flags
+
+### `-f --force`
+
+Force run all prepare steps even if outputs are fresh
+
+### `--list`
+
+Show what prepare steps are available
+
+### `-n --dry-run`
+
+Only check if prepare is needed, don't run commands
+
+### `--only… <ONLY>`
+
+Run specific prepare rule(s) only
+
+### `--skip… <SKIP>`
+
+Skip specific prepare rule(s)
+
+Examples:
+
+```
+mise prepare              # Run all applicable prepare steps
+mise prepare --dry-run    # Show what would run without executing
+mise prepare --force      # Force run even if outputs are fresh
+mise prepare --list       # List available prepare providers
+mise prepare --only npm   # Run only npm prepare
+mise prepare --skip npm   # Skip npm prepare
+```
+
+Configuration:
+
+```
+Configure prepare providers in mise.toml:
+
+```toml
+# Built-in npm provider (auto-detects lockfile)
+[prepare.npm]
+auto = true              # Auto-run before mise x/run
+
+# Custom provider
+[prepare.codegen]
+auto = true
+sources = ["schema/*.graphql"]
+outputs = ["src/generated/"]
+run = "npm run codegen"
+
+[prepare]
+disable = ["npm"]        # Disable specific providers at runtime
+```
+```

docs/cli/run.md

@@ -101,6 +101,10 @@ Tool(s) to run in addition to what is in mise.toml files e.g.: node@20 python@3.
 
 Do not use cache on remote tasks
 
+### `--no-prepare`
+
+Skip automatic dependency preparation
+
 ### `--no-timings`
 
 Hides elapsed time after each task completes

docs/cli/tasks/run.md

@@ -115,6 +115,10 @@ Tool(s) to run in addition to what is in mise.toml files e.g.: node@20 python@3.
 
 Do not use cache on remote tasks
 
+### `--no-prepare`
+
+Skip automatic dependency preparation
+
 ### `--no-timings`
 
 Hides elapsed time after each task completes

docs/dev-tools/prepare.md

@@ -0,0 +1,200 @@
+# Prepare <Badge type="warning" text="experimental" />
+
+The `mise prepare` command ensures project dependencies are ready by checking if lockfiles
+are newer than installed outputs (e.g., `package-lock.json` vs `node_modules/`) and running
+install commands if needed.
+
+## Quick Start
+
+```bash
+# Enable experimental features
+export MISE_EXPERIMENTAL=1
+
+# Run all applicable prepare steps
+mise prepare
+
+# Or use the alias
+mise prep
+```
+
+## Configuration
+
+Configure prepare providers in `mise.toml`:
+
+```toml
+# Built-in npm provider (auto-detects lockfile)
+[prepare.npm]
+auto = true  # Auto-run before mise x/run
+
+# Built-in providers for other package managers
+[prepare.yarn]
+[prepare.pnpm]
+[prepare.bun]
+[prepare.go]
+[prepare.pip]
+[prepare.poetry]
+[prepare.uv]
+[prepare.bundler]
+[prepare.composer]
+
+# Custom provider
+[prepare.codegen]
+auto = true
+sources = ["schema/*.graphql"]
+outputs = ["src/generated/"]
+run = "npm run codegen"
+
+# Disable specific providers
+[prepare]
+disable = ["npm"]
+```
+
+## Built-in Providers
+
+mise includes built-in providers for common package managers:
+
+| Provider   | Lockfile                  | Output                | Command                              |
+| ---------- | ------------------------- | --------------------- | ------------------------------------ |
+| `npm`      | `package-lock.json`       | `node_modules/`       | `npm install`                        |
+| `yarn`     | `yarn.lock`               | `node_modules/`       | `yarn install`                       |
+| `pnpm`     | `pnpm-lock.yaml`          | `node_modules/`       | `pnpm install`                       |
+| `bun`      | `bun.lockb` or `bun.lock` | `node_modules/`       | `bun install`                        |
+| `go`       | `go.mod`                  | `vendor/` or `go.sum` | `go mod vendor` or `go mod download` |
+| `pip`      | `requirements.txt`        | `.venv/`              | `pip install -r requirements.txt`    |
+| `poetry`   | `poetry.lock`             | `.venv/`              | `poetry install`                     |
+| `uv`       | `uv.lock`                 | `.venv/`              | `uv sync`                            |
+| `bundler`  | `Gemfile.lock`            | `vendor/bundle/`      | `bundle install`                     |
+| `composer` | `composer.lock`           | `vendor/`             | `composer install`                   |
+
+Built-in providers are only active when explicitly configured in `mise.toml` and their lockfile exists.
+
+## Custom Providers
+
+Create custom providers for project-specific build steps:
+
+```toml
+[prepare.codegen]
+sources = ["schema/*.graphql", "codegen.yml"]
+outputs = ["src/generated/"]
+run = "npm run codegen"
+description = "Generate GraphQL types"
+
+[prepare.prisma]
+sources = ["prisma/schema.prisma"]
+outputs = ["node_modules/.prisma/"]
+run = "npx prisma generate"
+```
+
+### Provider Options
+
+| Option        | Type     | Description                                              |
+| ------------- | -------- | -------------------------------------------------------- |
+| `auto`        | bool     | Auto-run before `mise x` and `mise run` (default: false) |
+| `sources`     | string[] | Files/patterns to check for changes                      |
+| `outputs`     | string[] | Files/directories that should be newer than sources      |
+| `run`         | string   | Command to run when stale                                |
+| `env`         | table    | Environment variables to set                             |
+| `dir`         | string   | Working directory for the command                        |
+| `description` | string   | Description shown in output                              |
+
+## Freshness Checking
+
+mise uses modification time (mtime) comparison to determine if outputs are stale:
+
+1. Find the most recent mtime among all source files
+2. Find the most recent mtime among all output files
+3. If any source is newer than all outputs, the provider is stale
+
+This means:
+
+- If you modify `package-lock.json`, `node_modules/` will be considered stale
+- If `node_modules/` doesn't exist, the provider is always stale
+- If sources don't exist, the provider is considered fresh (nothing to do)
+
+## Auto-Prepare
+
+When `auto = true` is set on a provider, it will automatically run before:
+
+- `mise run` (task execution)
+- `mise x` (exec command)
+
+This ensures dependencies are always up-to-date before running tasks or commands.
+
+To skip auto-prepare for a single invocation:
+
+```bash
+mise run --no-prepare build
+mise x --no-prepare -- npm test
+```
+
+## Staleness Warnings
+
+When using `mise activate`, mise will warn you if any auto-enabled providers have stale dependencies:
+
+```
+mise WARN prepare: npm may need update, run `mise prep`
+```
+
+This can be disabled with:
+
+```toml
+[settings]
+status.show_prepare_stale = false
+```
+
+## CLI Usage
+
+```bash
+# Run all applicable prepare steps
+mise prepare
+
+# Show what would run without executing
+mise prepare --dry-run
+
+# Force run even if outputs are fresh
+mise prepare --force
+
+# List available prepare providers
+mise prepare --list
+
+# Run only specific providers
+mise prepare --only npm --only codegen
+
+# Skip specific providers
+mise prepare --skip npm
+```
+
+## Parallel Execution
+
+Prepare providers run in parallel, respecting the `jobs` setting for concurrency limits.
+This speeds up preparation when multiple providers need to run (e.g., both npm and pip).
+
+```toml
+[settings]
+jobs = 4  # Run up to 4 providers in parallel
+```
+
+## Example: Full-Stack Project
+
+```toml
+# mise.toml for a project with Node.js frontend and Python backend
+
+[prepare.npm]
+auto = true
+
+[prepare.poetry]
+auto = true
+
+[prepare.prisma]
+auto = true
+sources = ["prisma/schema.prisma"]
+outputs = ["node_modules/.prisma/"]
+run = "npx prisma generate"
+
+[prepare.frontend-codegen]
+sources = ["schema.graphql", "codegen.ts"]
+outputs = ["src/generated/"]
+run = "npm run codegen"
+```
+
+Running `mise prep` will check all four providers and run any that are stale, in parallel.