feat: add chezmoi merge tools with VSCode integration and Fish helper

- Add VSCode-based merge helper with clear visual layout explanation
- Add Fish function for fzf-based interactive conflict selection
- Update CLAUDE.md with .tmpl file search patterns and tool usage guidelines

CLAUDE.md

@@ -66,6 +66,28 @@ When working in this repository, you're reading both the global AGENTS.md (gener
 - `encrypted_*.age` age-encrypted files (safe to commit)
 - `run_onchange_*` executable scripts that run during apply
 
+**Finding Files - Template Extension Patterns:**
+
+⚠️ **CRITICAL**: Most managed files have `.tmpl` extensions. Use wildcard patterns to find both base and `.tmpl` variants in one search.
+
+Common patterns where `.tmpl` is added to the FULL filename:
+- `config.md` → `config.md.tmpl` (NOT `config.tmpl`)
+- `settings.json` → `settings.json.tmpl` (NOT `settings.tmpl`)
+- `config.ts` → `config.ts.tmpl` (NOT `config.tmpl`)
+- `.bashrc` → `dot_bashrc.tmpl` (combines `dot_` and `.tmpl`)
+- `.config/opencode/opencode.jsonc` → `dot_config/opencode/opencode.jsonc.tmpl`
+
+**Search strategy - Use wildcards to catch both variants:**
+- Pattern: `**/filename*` (e.g., `**/CLAUDE.md*` finds both `CLAUDE.md` AND `CLAUDE.md.tmpl`)
+- Pattern: `**/*.ext.tmpl` for type-specific template files (e.g., `**/*.ts.tmpl`, `**/*.json.tmpl`)
+- Check both `home/` and `home/.chezmoitemplates/` directories
+
+**Examples:**
+- Looking for "CLAUDE.md"? → Search `**/CLAUDE.md*` (finds both base and `.tmpl`)
+- Looking for "config.nu"? → Search `**/config.nu*` (finds both variants)
+- Looking for all TypeScript templates? → Search `**/*.ts.tmpl`
+- Looking for all JSON configs? → Search `**/*.json*` (finds `.json` and `.json.tmpl`)
+
 **Template System:**
 - Uses Go templates with platform detection
 - Two types of templates with different variable access patterns:

home/.chezmoi.toml.tmpl

@@ -45,10 +45,11 @@
 encryption = "age"
 
 [merge]
-command = "bash"
+command = "chezmoi-merge-helper.sh"
 args = [
-	"-c",
+	"{{ "{{" }} .Destination {{ "}}" }}",
-	"cp {{ "{{" }} .Target {{ "}}" }} {{ "{{" }} .Target {{ "}}" }}.base && code --new-window --wait --merge {{ "{{" }} .Destination {{ "}}" }} {{ "{{" }} .Target {{ "}}" }} {{ "{{" }} .Target {{ "}}" }}.base {{ "{{" }} .Source {{ "}}" }}",
+	"{{ "{{" }} .Target {{ "}}" }}",
+	"{{ "{{" }} .Source {{ "}}" }}",
 ]
 
 [data]

home/dot_claude/CLAUDE.md.tmpl

@@ -221,38 +221,88 @@ When a project uses `assert2`:
 - Grep tool for searching (not `grep`, `rg`)
 - Bash ONLY for actual system commands and terminal operations
 
-### GitHub File Fetching
+### GitHub & External Resources
 
-When fetching files from GitHub repositories:
+**Fetching file content from GitHub:**
 
 - **STRONGLY prefer raw.githubusercontent.com over github.com**
   - Raw URLs return plain content without HTML wrapper - simpler and faster
   - Pattern: `https://raw.githubusercontent.com/{owner}/{repo}/{branch}/{path}`
-  - Example: `https://raw.githubusercontent.com/user/repo/main/src/file.rs`
+  - For specific commits/tags: `https://raw.githubusercontent.com/{owner}/{repo}/{commit-sha}/{path}`
   - Only use github.com URLs when you need the web interface or rendered view
 
-- **Use GitHub CLI (`gh`) for repository operations**
+**GitHub CLI (`gh`) for everything else:**
-  - Perfect for metadata and repository management
-  - Examples: `gh repo view`, `gh issue list`, `gh pr view`, `gh pr checkout`
-  - More reliable than web scraping for structured data
 
-- **Use MCP gh_grep tool for code search** (see below)
+- **Authenticated API access** - use `gh api` for direct GitHub API calls:
+  - `gh api repos/{owner}/{repo}/releases/latest` - get latest release info
+  - `gh api repos/{owner}/{repo}/contents/{path}` - get file metadata/content
+  - `gh api repos/{owner}/{repo}` - get repository details
+  - Supports GraphQL: `gh api graphql -f query='...'`
+
+- **Search GitHub** - use `gh search` subcommands:
+  - `gh search repos "query"` - find repositories
+  - `gh search issues "query" --repo owner/repo` - search issues
+  - `gh search code "query"` - GitHub's native code search (different from gh_grep)
+
+- **Repository operations** - metadata and management:
+  - `gh repo view owner/repo` - repository info
+  - `gh release list -R owner/repo` - list releases with versions
+  - `gh issue/pr view` - issue and PR details
 
 ### MCP Tools (When Available)
 
-**gh_grep (GitHub Code Search)**
+**gh_grep - CRITICAL: THIS IS LITERAL PATTERN MATCHING, NOT SEMANTIC SEARCH**
-- Search real-world code examples from 1M+ public repos
+
-- Use for: unfamiliar APIs, usage patterns, real implementation examples
+This tool searches for **exact character sequences** in source code files. It is `grep`, not Google.
-- Search for **literal code**, not keywords: `'useState('`, `'async function'`, `'import React from'`
+
-- Use regex with `useRegexp: true` for flexible patterns: `'(?s)useEffect\\(\\(\\) => {.*cleanup'`
+It CANNOT:
-- Filter by `language`, `repo`, or `path` to narrow results
+- Understand what you're looking for conceptually
-- Perfect for seeing how others solve similar problems
+- Find "related" code or similar patterns
+- Interpret natural language or keywords
+
+❌ **WRONG** - these will fail or return garbage:
+- `"how to handle errors"` → literally searches for that sentence in code
+- `"authentication"` → only finds that exact word as a string, not auth implementations
+- `"best practices"` → completely useless
+- `"react state management"` → meaningless as a code pattern
+
+✅ **CORRECT** - search for actual code that appears in source files:
+- `'useAuth('` → finds useAuth function calls
+- `'catch (AuthError'` → finds specific error handling
+- `'implements OAuth'` → finds class implementations
+- `'(?s)async function.*await fetch'` with `useRegexp: true` → async functions with fetch
+
+**Rule of thumb**: If your query wouldn't make sense copy-pasted into a source file, it's wrong.
+
+Use `language`, `repo`, and `path` filters to narrow results.
 
 **context7 (Library Documentation)**
 - Get up-to-date docs for libraries/frameworks
-- Two-step process: `resolve-library-id` → `get-library-docs`
+- Two-step process: `resolve-library-id` → `query-docs`
-- Use `mode: 'code'` for API references (default), `mode: 'info'` for guides
+- Prefer when you need official documentation vs community examples from gh_grep
-- Prefer when you need official docs vs community examples
+
+## Useful CLI Tools
+
+Prefer these over convoluted bash pipelines or manual parsing.
+
+**JSON Processing (`jq`):**
+- Use for parsing API responses, transforming configs, extracting data
+- Example: `gh api repos/owner/repo/releases | jq '.[0] | {tag: .tag_name, date: .published_at}'`
+- Pipe any JSON output through jq for readable formatting: `... | jq .`
+
+**Quick TypeScript Scripts (`bun`):**
+- When shell gets too complex, write a quick inline script instead
+- Prefer over chained `sed`/`awk`/`grep` pipelines for data transformation
+- Example: `bun -e "console.log(JSON.parse(require('fs').readFileSync('data.json')).items.filter(x => x.active).length)"`
+- Can also run `.ts` files directly: `bun run script.ts`
+
+**Benchmarking (`hyperfine`):**
+- Compare command performance: `hyperfine 'command1' 'command2'`
+- Useful for verifying optimization claims
+
+**Codebase Statistics (`tokei`):**
+- Quick language breakdown and LOC counts: `tokei .`
+- Useful for understanding unfamiliar codebases
 
 ## Security & Error Handling
 

home/dot_config/fish/functions/chmerge.fish

@@ -0,0 +1,30 @@
+function chmerge --description "Interactively merge chezmoi conflicts using fzf"
+    # Get files with merge conflicts (MM = modified in both source and target)
+    set -l conflict_files (chezmoi status | grep '^MM ' | awk '{print $2}')
+
+    if test (count $conflict_files) -eq 0
+        echo "No merge conflicts found."
+        return 0
+    end
+
+    # Use fzf for selection with multi-select enabled
+    set -l selected (printf '%s\n' $conflict_files | fzf \
+        --multi \
+        --preview 'chezmoi diff {}' \
+        --preview-window 'right:70%:wrap' \
+        --header 'Select files to merge (Tab for multi-select, Enter to confirm)' \
+        --bind 'ctrl-/:toggle-preview')
+
+    if test (count $selected) -eq 0
+        echo "No files selected."
+        return 0
+    end
+
+    # Convert to absolute target paths and merge
+    for file in $selected
+        # Expand ~ to home directory for chezmoi merge
+        set -l target_path (string replace -r '^~' $HOME $file)
+        echo "Merging: $file"
+        chezmoi merge $target_path
+    end
+end

home/dot_local/bin/executable_chezmoi-merge-helper.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+# Helper script for chezmoi merge with clear labels
+# Arguments: $1=destination $2=target $3=source
+
+destination="$1"
+target="$2"
+source="$3"
+
+# Create base file (copy of target state)
+base="${target}.base"
+cp "$target" "$base"
+
+# Show clear explanation before merge
+cat << EOF
+╔════════════════════════════════════════════════════════════════╗
+║                    CHEZMOI MERGE LAYOUT                        ║
+╠════════════════════════════════════════════════════════════════╣
+║                                                                ║
+║  LEFT (Current):    DESTINATION - File in your home dir       ║
+║                     ↓ External changes (e.g., app updates)    ║
+║                                                                ║
+║  RIGHT (Incoming):  TARGET - What chezmoi wants to apply      ║
+║                     ↓ Your chezmoi changes (templates, etc)   ║
+║                                                                ║
+║  BOTTOM (Result):   SOURCE - Will be saved to chezmoi repo    ║
+║                                                                ║
+╠════════════════════════════════════════════════════════════════╣
+║  File: $(basename "$destination")
+╚════════════════════════════════════════════════════════════════╝
+
+Press Enter to open merge editor...
+EOF
+
+read -r
+
+# Launch VSCode merge
+# Syntax: code --merge <current> <incoming> <base> <result>
+code --new-window --wait --merge "$destination" "$target" "$base" "$source"
+
+# Cleanup
+rm -f "$base"