feat: add migrate command for agents.md standard

CHANGELOG.md

@@ -0,0 +1,14 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- **`ai-rules migrate`** – One-way migration from the ai-rules–managed layout to the [agents.md](https://agents.md/) standard: writes root `AGENTS.md`, moves `ai-rules/skills` and `ai-rules/commands` into `.agents/`, removes generated files, and purges the `ai-rules/` directory. Supports `--nested-depth`, `--dry-run`, and `--force`; prompts for confirmation unless `--force` or `--dry-run`. See [Migration guide](docs/migration.md).
+
+## [1.5.0] - (see GitHub releases)

README.md

@@ -61,6 +61,7 @@ curl -fsSL https://raw.githubusercontent.com/block/ai-rules/main/scripts/install
 | `ai-rules generate` | Generate rules for AI coding agents |
 | `ai-rules status` | Show sync status of AI rules |
 | `ai-rules clean` | Remove all generated files |
+| `ai-rules migrate` | Migrate from ai-rules/ layout to agents.md standard (one-way) |
 | `ai-rules list-agents` | List all supported agents |
 
 ### Common Options
@@ -89,6 +90,10 @@ AMP, Claude Code, Cline, Codex, Copilot, Cursor, Firebender, Gemini, Goose, Kilo
 
 See [Supported Agents](docs/agents.md) for detailed compatibility information.
 
+## Migration to agents.md standard
+
+You can migrate from the ai-rules–managed layout to the [agents.md](https://agents.md/) standard: a single `AGENTS.md` at project root, skills in `.agents/skills/`, and commands in `.agents/commands/`. Run `ai-rules migrate` to write root `AGENTS.md`, move `ai-rules/skills` and `ai-rules/commands` into `.agents/`, remove generated files, and purge the `ai-rules/` directory. **This is one-way**; after migrating, the project no longer uses ai-rules generate/clean/status for that content. Use `--dry-run` first to see what would be done, then run without it (and confirm) or with `--force` to migrate. See [Migration guide](docs/migration.md) for details.
+
 ## Documentation
 
 - [Configuration](docs/configuration.md) - Config file options and precedence
@@ -97,6 +102,7 @@ See [Supported Agents](docs/agents.md) for detailed compatibility information.
 - [MCP Configuration](docs/mcp.md) - Model Context Protocol setup
 - [Commands and Skills](docs/commands-and-skills.md) - Custom commands and skills
 - [Project Structure](docs/project-structure.md) - Example project layouts
+- [Migration to agents.md](docs/migration.md) - One-way migration from ai-rules/ layout
 
 ## Development
 

docs/migration.md

@@ -0,0 +1,57 @@
+# Migration to agents.md standard
+
+This guide describes how to migrate from the ai-rules–managed layout to the [agents.md](https://agents.md/) standard layout using `ai-rules migrate`. The migration is **one-way**: after migrating, the project no longer uses `ai-rules generate`, `ai-rules clean`, or `ai-rules status` for that content.
+
+## Prerequisites
+
+- Your project has an `ai-rules/` directory (created by `ai-rules init` or manually).
+- **Back up** the `ai-rules/` directory if you want to keep the original layout; migration cannot be automatically reverted.
+
+## Command options
+
+| Option | Description |
+|--------|-------------|
+| `--nested-depth <N>` | Maximum nested directory depth to traverse (0 = current directory only). Same precedence as other commands: CLI overrides config file. |
+| `--dry-run` | Print what would be done without writing or deleting. **Recommended first step.** |
+| `--force` | Skip the confirmation prompt and run migration. |
+
+## Confirmation behavior
+
+- **With `--dry-run`**: No confirmation; the command only prints which directories would be migrated and what actions would be performed.
+- **With `--force`**: No confirmation; migration runs immediately.
+- **Without `--dry-run` or `--force`**: The command lists how many project(s) would be migrated, shows a warning that the change cannot be undone, and prompts: *"Proceed with migration? (y/N)"*. If you answer no, nothing is changed.
+
+**Recommendation:** Run `ai-rules migrate --dry-run` first to see the list of directories and actions, then run `ai-rules migrate` (and confirm) or `ai-rules migrate --force` to perform the migration.
+
+## What is written where
+
+| Outcome | Description |
+|--------|-------------|
+| **Root `AGENTS.md`** | A single self-contained markdown file at the project root. In **symlink mode** (single `ai-rules/AGENTS.md` with no YAML frontmatter), its content is a copy of that file. In **standard mode** (multiple `.md` rules with frontmatter), content is the inlined combination of all rules (no `@` file references). |
+| **`.agents/skills/`** | The directory `ai-rules/skills/` is **moved** here. The whole tree is relocated; nothing is left under `ai-rules/`. |
+| **`.agents/commands/`** | The directory `ai-rules/commands/` is **moved** here. Same as skills. |
+| **Other `ai-rules/` subdirs** | Any other non-generated directories under `ai-rules/` (e.g. custom dirs) are moved into `.agents/` with the same name so `ai-rules/` can be fully removed. |
+| **Root `.mcp.json`** | If `ai-rules/mcp.json` existed, it is moved to the project root as `.mcp.json` so tools that read MCP from root (e.g. Claude Code) can use it. |
+
+## What is removed
+
+- **Generated files and symlinks**: All outputs previously created by `ai-rules generate` are removed (e.g. `CLAUDE.md`, `GEMINI.md`, `.cursor/rules/*.mdc`, `firebender.json`, command/skill symlinks in `.claude`, `.cursor`, `.agents`, etc.), using the same logic as `ai-rules clean`.
+- **`ai-rules/` directory**: After moving content out and running the equivalent of clean, the entire `ai-rules/` directory is deleted.
+
+## .gitignore behavior
+
+The block between `# AI Rules - Generated Files` and `# End AI Rules` is removed from the project’s `.gitignore`. No new entries are added for `.agents/`; the new layout is intended to be committed.
+
+## What is not migrated
+
+- **`ai-rules-config.yaml`** and **`ai-rules/firebender-overlay.json`** are not copied; they become obsolete. If you use Firebender or other tools that relied on generated paths, reconfigure them to point at root `AGENTS.md` if desired.
+- **Cursor `.cursor/rules/*.mdc`** and **Firebender `firebender.json`** are not regenerated from the new layout; those tools would need to be pointed at root `AGENTS.md` manually if you want to use them with the new layout.
+
+## Nested / monorepo usage
+
+Migration runs per directory. Each directory that has its own `ai-rules/` gets its own root `AGENTS.md` and `.agents/` at that directory (e.g. `frontend/AGENTS.md`, `frontend/.agents/`). Use `--nested-depth` to control how many levels are traversed (same as `generate` and `clean`).
+
+## After migration
+
+- The project no longer uses ai-rules for that content. To use ai-rules again you would need to recreate `ai-rules/` and run `generate` (not automated).
+- Tools that read `AGENTS.md` / `AGENTS(S).md` and `.agents/` (e.g. [agents.md](https://agents.md/)) can use the new layout directly.

src/cli/args.rs

@@ -32,6 +32,8 @@ pub enum Commands {
     Status(StatusArgs),
     /// Clean up generated files
     Clean(CleanArgs),
+    /// Migrate from ai-rules/ layout to agents.md standard (one-way)
+    Migrate(MigrateArgs),
     /// List all supported coding agents
     ListAgents,
 }
@@ -113,6 +115,24 @@ pub struct CleanArgs {
     pub nested_depth_args: NestedDepthArgs,
 }
 
+#[derive(Args)]
+#[command(after_help = "Examples:
+  ai-rules migrate                    # Migrate current directory only (nested_depth 0)
+  ai-rules migrate --nested-depth 2    # Migrate ai-rules/ in nested directories
+
+Migrates from ai-rules/ layout to agents.md standard: writes AGENTS.md at project root,
+moves ai-rules/skills and ai-rules/commands (and other ai-rules subdirs) into .agents/,
+removes generated files and purges the ai-rules/ directory. One-way. Prompts for confirmation
+unless --force or --dry-run. Run only when ready to adopt the standard. Use --dry-run first.")]
+pub struct MigrateArgs {
+    #[command(flatten)]
+    pub nested_depth_args: NestedDepthArgs,
+    #[arg(long, help = "Print what would be done without writing or deleting")]
+    pub dry_run: bool,
+    #[arg(long, help = "Skip confirmation prompt and run migration (default: prompt before migrating)")]
+    pub force: bool,
+}
+
 #[derive(Debug, Clone)]
 pub struct ResolvedGenerateArgs {
     pub agents: Option<Vec<String>>,

src/cli/mod.rs

@@ -6,7 +6,7 @@ mod tests;
 
 pub use args::*;
 
-use crate::commands::{run_clean, run_generate, run_init, run_list_agents, run_status};
+use crate::commands::{run_clean, run_generate, run_init, run_list_agents, run_migrate, run_status};
 use crate::config;
 use clap::Parser;
 
@@ -43,6 +43,10 @@ pub fn run_cli() -> anyhow::Result<()> {
             let nested_depth = args.nested_depth_args.with_config(config.as_ref());
             run_clean(&current_dir, nested_depth, use_claude_skills)
         }
+        Some(Commands::Migrate(args)) => {
+            let nested_depth = args.nested_depth_args.with_config(config.as_ref());
+            run_migrate(&current_dir, nested_depth, args.dry_run, args.force)
+        }
         Some(Commands::ListAgents) => run_list_agents(use_claude_skills),
         None => {
             // If no command is provided and --summary is not used, show help

src/commands/migrate.rs

@@ -0,0 +1,66 @@
+use crate::operations;
+use crate::utils::file_utils;
+use crate::utils::prompt_utils::prompt_yes_no;
+use anyhow::Result;
+use std::path::Path;
+
+pub fn run_migrate(
+    current_dir: &Path,
+    nested_depth: usize,
+    dry_run: bool,
+    force: bool,
+) -> Result<()> {
+    // Discover all directories that would be migrated
+    let mut to_migrate = Vec::new();
+    file_utils::traverse_project_directories(current_dir, nested_depth, 0, &mut |dir| {
+        if operations::migrate::should_migrate(dir) {
+            to_migrate.push(dir.to_path_buf());
+        }
+        Ok(())
+    })?;
+
+    if to_migrate.is_empty() {
+        println!("No ai-rules/ directories found to migrate.");
+        return Ok(());
+    }
+
+    if dry_run {
+        println!("Dry run: would migrate {} project(s) to the agents.md standard:", to_migrate.len());
+        for path in &to_migrate {
+            println!("  {}", path.display());
+        }
+    } else if !force {
+        println!(
+            "This will migrate {} project(s) to the agents.md standard and remove ai-rules/ directories. This cannot be undone.",
+            to_migrate.len()
+        );
+        if !prompt_yes_no("Proceed with migration?")? {
+            println!("Migration cancelled.");
+            return Ok(());
+        }
+    }
+
+    let mut results = Vec::new();
+    for dir in &to_migrate {
+        let result = operations::migrate::run_migration_for_dir(dir, dry_run)?;
+        results.push(result);
+    }
+
+    // Summary
+    let migrated: Vec<_> = results.iter().filter(|r| !r.skipped).collect();
+    if migrated.is_empty() && !dry_run {
+        println!("No directories were migrated.");
+    } else if dry_run {
+        for r in &results {
+            if !r.skipped {
+                println!("  {}: would {}", r.path.display(), r.actions.join(", "));
+            }
+        }
+    } else {
+        for r in &migrated {
+            println!("Migrated {}: {}", r.path.display(), r.actions.join(", "));
+        }
+    }
+
+    Ok(())
+}

src/commands/mod.rs

@@ -2,12 +2,14 @@ mod clean;
 mod generate;
 mod init;
 mod list_agents;
+mod migrate;
 mod status;
 
 pub use clean::run_clean;
 pub use generate::run_generate;
 pub use init::run_init;
 pub use list_agents::run_list_agents;
+pub use migrate::run_migrate;
 pub use status::run_status;
 
 #[cfg(test)]

src/operations/gitignore_updater.rs

@@ -64,7 +64,7 @@ fn collect_all_gitignore_patterns(
     }
 }
 
-fn remove_ai_rules_section(content: String) -> String {
+pub(crate) fn remove_ai_rules_section(content: String) -> String {
     if let Some(start) = content.find("# AI Rules - Generated Files") {
         if let Some(end) = content.find("# End AI Rules") {
             let mut result = content;
@@ -105,6 +105,20 @@ fn update_gitignore(current_dir: &Path, patterns: Vec<String>) -> Result<()> {
     Ok(())
 }
 
+/// Removes the "# AI Rules - Generated Files" / "# End AI Rules" block from a .gitignore file at the given path.
+/// No-op if the file does not exist or the section is not present.
+pub fn remove_ai_rules_section_from_file(gitignore_path: &Path) -> Result<()> {
+    if !gitignore_path.exists() {
+        return Ok(());
+    }
+    let content = fs::read_to_string(gitignore_path)?;
+    let new_content = remove_ai_rules_section(content.clone());
+    if new_content != content {
+        fs::write(gitignore_path, new_content)?;
+    }
+    Ok(())
+}
+
 pub fn remove_gitignore_section(current_dir: &Path, registry: &AgentToolRegistry) -> Result<()> {
     let gitignore_path = current_dir.join(".gitignore");