fix: replace ! with [BANG] placeholder in skill documentation (#142)

## Summary

- Replace `!` followed by backticks with `[BANG]` placeholder in
command-development skill files
- Prevents bash execution errors when skills are loaded into Claude's
context

## Problem

Skill documentation containing the `!` prefix (used for pre-execution in
slash commands) triggers unintended bash execution when the skill
content is loaded. This causes errors like:

```
Bash command permission check failed for pattern "!`...": Command contains newlines...
```

## Solution

Use `[BANG]` as a placeholder in skill documentation. When Claude
explains the concept to users, it correctly renders the actual `!`
syntax they should use in their command files.

## Related Issue

Workaround for anthropics/claude-code#12781

## Test plan

- [x] Load plugin locally with `cc --plugin-dir plugins/plugin-dev`
- [x] Trigger skill loading by asking about command development
- [x] Trigger reference file loading by asking about CLAUDE_PLUGIN_ROOT
- [x] Verify no bash execution errors occur

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: sjnims

plugins/plugin-dev/skills/command-development/SKILL.md

@@ -337,28 +337,28 @@ Ensure:
 
 Commands can execute bash commands inline to dynamically gather context before Claude processes the command. This is useful for including repository state, environment information, or project-specific context.
 
-### Syntax: The `!` Prefix
+### Syntax: The `[BANG]` Prefix
 
-In actual command files, use the `!` prefix before backticks for pre-execution:
+In actual command files, use `[BANG]` (exclamation mark) before backticks for pre-execution:
 
 ```markdown
-Current branch: !`git branch --show-current`
-Files changed: !`git diff --name-only`
-Environment: !`echo $NODE_ENV`
+Current branch: [BANG]`git branch --show-current`
+Files changed: [BANG]`git diff --name-only`
+Environment: [BANG]`echo $NODE_ENV`
 ```
 
 **How it works:**
 
-1. Before Claude sees the command, Claude Code executes `!`command`` blocks
-2. The bash output replaces the entire `!`command`` expression
+1. Before Claude sees the command, Claude Code executes `[BANG]`command`` blocks
+2. The bash output replaces the entire `[BANG]`command`` expression
 3. Claude receives the expanded prompt with actual values
 
 **Example expansion:**
 
 Command file contains:
 
 ```markdown
-Review the !`git diff --name-only | wc -l | tr -d ' '` changed files on branch !`git branch --show-current`.
+Review the [BANG]`git diff --name-only | wc -l | tr -d ' '` changed files on branch [BANG]`git branch --show-current`.
 ```
 
 Claude receives (after pre-execution):
@@ -367,15 +367,15 @@ Claude receives (after pre-execution):
 Review the 3 changed files on branch feature/add-auth.
 ```
 
-### Why Skill Examples Omit `!`
+### Why Skill Examples Omit `[BANG]`
 
-Examples in skill documentation use plain backticks without `!`:
+Examples in skill documentation use plain backticks without `[BANG]`:
 
 ```markdown
 Files changed: `git diff --name-only`
 ```
 
-This is intentional. When skill content loads into Claude's context, `!`command`` would actually execute. Skill examples show the conceptual pattern; add the `!` prefix when writing actual command files.
+This is intentional. When skill content loads into Claude's context, `[BANG]` followed by `[command name]` would actually execute. Skill examples show the conceptual pattern; add the `[BANG]` prefix when writing actual command files.
 
 **When to use:**
 

plugins/plugin-dev/skills/command-development/references/plugin-features-reference.md

@@ -94,7 +94,7 @@ description: Analyze using plugin script
 allowed-tools: Bash(node:*), Read
 ---
 
-Run analysis: !`node ${CLAUDE_PLUGIN_ROOT}/scripts/analyze.js`
+Run analysis: [BANG]`node ${CLAUDE_PLUGIN_ROOT}/scripts/analyze.js`
 
 Read template: @${CLAUDE_PLUGIN_ROOT}/templates/report.md
 ```
@@ -117,7 +117,7 @@ description: Run custom linter from plugin
 allowed-tools: Bash(node:*)
 ---
 
-Lint results: !`node ${CLAUDE_PLUGIN_ROOT}/bin/lint.js $1`
+Lint results: [BANG]`node ${CLAUDE_PLUGIN_ROOT}/bin/lint.js $1`
 
 Review the linting output and suggest fixes.
 ```
@@ -155,9 +155,9 @@ description: Complete plugin workflow
 allowed-tools: Bash(*), Read
 ---
 
-Step 1 - Prepare: !`bash ${CLAUDE_PLUGIN_ROOT}/scripts/prepare.sh $1`
+Step 1 - Prepare: [BANG]`bash ${CLAUDE_PLUGIN_ROOT}/scripts/prepare.sh $1`
 Step 2 - Config: @${CLAUDE_PLUGIN_ROOT}/config/$1.json
-Step 3 - Execute: !`${CLAUDE_PLUGIN_ROOT}/bin/execute $1`
+Step 3 - Execute: [BANG]`${CLAUDE_PLUGIN_ROOT}/bin/execute $1`
 
 Review results and report status.
 ```
@@ -180,7 +180,7 @@ Review results and report status.
    allowed-tools: Bash(test:*), Read
    ---
 
-   !`test -f ${CLAUDE_PLUGIN_ROOT}/config.json && echo "exists" || echo "missing"`
+   [BANG]`test -f ${CLAUDE_PLUGIN_ROOT}/config.json && echo "exists" || echo "missing"`
 
    If config exists, load it: @${CLAUDE_PLUGIN_ROOT}/config.json
    Otherwise, use defaults...
@@ -199,7 +199,7 @@ Review results and report status.
 
 4. **Combine with arguments:**
    ```markdown
-   Run: !`${CLAUDE_PLUGIN_ROOT}/bin/process.sh $1 $2`
+   Run: [BANG]`${CLAUDE_PLUGIN_ROOT}/bin/process.sh $1 $2`
    ```
 
 ### Troubleshooting
@@ -235,8 +235,8 @@ Load configuration: @${CLAUDE_PLUGIN_ROOT}/deploy-config.json
 
 Deploy to $1 environment using:
 1. Configuration settings above
-2. Current git branch: !`git branch --show-current`
-3. Application version: !`cat package.json | grep version`
+2. Current git branch: [BANG]`git branch --show-current`
+3. Application version: [BANG]`cat package.json | grep version`
 
 Execute deployment and monitor progress.
 ```
@@ -275,9 +275,9 @@ description: Complete build and test workflow
 allowed-tools: Bash(*)
 ---
 
-Build: !`bash ${CLAUDE_PLUGIN_ROOT}/scripts/build.sh`
-Validate: !`bash ${CLAUDE_PLUGIN_ROOT}/scripts/validate.sh`
-Test: !`bash ${CLAUDE_PLUGIN_ROOT}/scripts/test.sh`
+Build: [BANG]`bash ${CLAUDE_PLUGIN_ROOT}/scripts/build.sh`
+Validate: [BANG]`bash ${CLAUDE_PLUGIN_ROOT}/scripts/validate.sh`
+Test: [BANG]`bash ${CLAUDE_PLUGIN_ROOT}/scripts/test.sh`
 
 Review all outputs and report:
 1. Build status
@@ -300,7 +300,7 @@ argument-hint: [dev|staging|prod]
 
 Environment config: @${CLAUDE_PLUGIN_ROOT}/config/$1.json
 
-Environment check: !`echo "Deploying to: $1"`
+Environment check: [BANG]`echo "Deploying to: $1"`
 
 Deploy application using $1 environment configuration.
 Verify deployment and run smoke tests.
@@ -321,7 +321,7 @@ allowed-tools: Bash(*), Read, Write
 Cache directory: ${CLAUDE_PLUGIN_ROOT}/cache/
 
 Analyze @$1 and save results to cache:
-!`mkdir -p ${CLAUDE_PLUGIN_ROOT}/cache && date > ${CLAUDE_PLUGIN_ROOT}/cache/last-run.txt`
+[BANG]`mkdir -p ${CLAUDE_PLUGIN_ROOT}/cache && date > ${CLAUDE_PLUGIN_ROOT}/cache/last-run.txt`
 
 Store analysis for future reference and comparison.
 ```
@@ -393,9 +393,9 @@ description: Commit with pre-commit validation
 allowed-tools: Bash(git:*)
 ---
 
-Stage changes: !`git add $1`
+Stage changes: [BANG]`git add $1`
 
-Commit changes: !`git commit -m "$2"`
+Commit changes: [BANG]`git commit -m "$2"`
 
 Note: This commit will trigger the plugin's pre-commit hook for validation.
 Review hook output for any issues.
@@ -421,7 +421,7 @@ File to review: @$1
 Execute comprehensive review:
 
 1. **Static Analysis** (via plugin scripts)
-   !`node ${CLAUDE_PLUGIN_ROOT}/scripts/lint.js $1`
+   [BANG]`node ${CLAUDE_PLUGIN_ROOT}/scripts/lint.js $1`
 
 2. **Deep Review** (via plugin agent)
    Launch the code-reviewer agent for detailed analysis.
@@ -449,7 +449,7 @@ description: Deploy to environment with validation
 argument-hint: [environment]
 ---
 
-Validate environment: !`echo "$1" | grep -E "^(dev|staging|prod)$" || echo "INVALID"`
+Validate environment: [BANG]`echo "$1" | grep -E "^(dev|staging|prod)$" || echo "INVALID"`
 
 $IF($1 in [dev, staging, prod],
   Deploy to $1 environment using validated configuration,
@@ -472,7 +472,7 @@ description: Process configuration file
 argument-hint: [config-file]
 ---
 
-Check file: !`test -f $1 && echo "EXISTS" || echo "MISSING"`
+Check file: [BANG]`test -f $1 && echo "EXISTS" || echo "MISSING"`
 
 Process configuration if file exists: @$1
 
@@ -492,7 +492,7 @@ description: Create deployment with version
 argument-hint: [environment] [version]
 ---
 
-Validate inputs: !`test -n "$1" -a -n "$2" && echo "OK" || echo "MISSING"`
+Validate inputs: [BANG]`test -n "$1" -a -n "$2" && echo "OK" || echo "MISSING"`
 
 $IF($1 AND $2,
   Deploy version $2 to $1 environment,
@@ -511,9 +511,9 @@ allowed-tools: Bash(test:*)
 ---
 
 Validate plugin setup:
-- Config exists: !`test -f ${CLAUDE_PLUGIN_ROOT}/config.json && echo "✓" || echo "✗"`
-- Scripts exist: !`test -d ${CLAUDE_PLUGIN_ROOT}/scripts && echo "✓" || echo "✗"`
-- Tools available: !`test -x ${CLAUDE_PLUGIN_ROOT}/bin/analyze && echo "✓" || echo "✗"`
+- Config exists: [BANG]`test -f ${CLAUDE_PLUGIN_ROOT}/config.json && echo "✓" || echo "✗"`
+- Scripts exist: [BANG]`test -d ${CLAUDE_PLUGIN_ROOT}/scripts && echo "✓" || echo "✗"`
+- Tools available: [BANG]`test -x ${CLAUDE_PLUGIN_ROOT}/bin/analyze && echo "✓" || echo "✗"`
 
 If all checks pass, proceed with analysis.
 Otherwise, report missing components and installation steps.
@@ -529,12 +529,12 @@ description: Build and validate output
 allowed-tools: Bash(*)
 ---
 
-Build: !`bash ${CLAUDE_PLUGIN_ROOT}/scripts/build.sh`
+Build: [BANG]`bash ${CLAUDE_PLUGIN_ROOT}/scripts/build.sh`
 
 Validate output:
-- Exit code: !`echo $?`
-- Output exists: !`test -d dist && echo "✓" || echo "✗"`
-- File count: !`find dist -type f | wc -l`
+- Exit code: [BANG]`echo $?`
+- Output exists: [BANG]`test -d dist && echo "✓" || echo "✗"`
+- File count: [BANG]`find dist -type f | wc -l`
 
 Report build status and any validation failures.
 ```
@@ -549,7 +549,7 @@ description: Process file with error handling
 argument-hint: [file-path]
 ---
 
-Try processing: !`node ${CLAUDE_PLUGIN_ROOT}/scripts/process.js $1 2>&1 || echo "ERROR: $?"`
+Try processing: [BANG]`node ${CLAUDE_PLUGIN_ROOT}/scripts/process.js $1 2>&1 || echo "ERROR: $?"`
 
 If processing succeeded:
 - Report results