Add auto-slash-command hook for intercepting and replacing slash commands

This hook intercepts user messages starting with '/' and REPLACES them with the actual command template output instead of injecting instructions. The implementation includes:

- Slash command detection (detector.ts) - identifies messages starting with '/'
- Command discovery and execution (executor.ts) - loads templates from ~/.claude/commands/ or similar
- Hook integration (index.ts) - registers with chat.message event to replace output.parts
- Comprehensive test coverage - 37 tests covering detection, replacement, error handling, and command exclusions
- Configuration support in HookNameSchema

Key features:
- Supports excluded commands to skip processing
- Loads command templates from user's command directory
- Replaces user input before reaching the LLM
- Tests all edge cases including missing files, malformed templates, and special commands

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

Author: code-yeongyu

src/config/schema.ts

@@ -69,6 +69,7 @@ export const HookNameSchema = z.enum([
   "preemptive-compaction",
   "compaction-context-injector",
   "claude-code-hooks",
+  "auto-slash-command",
 ])
 
 export const BuiltinCommandNameSchema = z.enum([

src/hooks/auto-slash-command/constants.ts

@@ -0,0 +1,11 @@
+export const HOOK_NAME = "auto-slash-command" as const
+
+export const AUTO_SLASH_COMMAND_TAG_OPEN = "<auto-slash-command>"
+export const AUTO_SLASH_COMMAND_TAG_CLOSE = "</auto-slash-command>"
+
+export const SLASH_COMMAND_PATTERN = /^\/([a-zA-Z][\w-]*)\s*(.*)/
+
+export const EXCLUDED_COMMANDS = new Set([
+  "ralph-loop",
+  "cancel-ralph",
+])

src/hooks/auto-slash-command/detector.test.ts

@@ -0,0 +1,296 @@
+import { describe, expect, it } from "bun:test"
+import {
+  parseSlashCommand,
+  detectSlashCommand,
+  isExcludedCommand,
+  removeCodeBlocks,
+  extractPromptText,
+} from "./detector"
+
+describe("auto-slash-command detector", () => {
+  describe("removeCodeBlocks", () => {
+    it("should remove markdown code blocks", () => {
+      // #given text with code blocks
+      const text = "Hello ```code here``` world"
+
+      // #when removing code blocks
+      const result = removeCodeBlocks(text)
+
+      // #then code blocks should be removed
+      expect(result).toBe("Hello  world")
+    })
+
+    it("should remove multiline code blocks", () => {
+      // #given text with multiline code blocks
+      const text = `Before
+\`\`\`javascript
+/command-inside-code
+\`\`\`
+After`
+
+      // #when removing code blocks
+      const result = removeCodeBlocks(text)
+
+      // #then code blocks should be removed
+      expect(result).toContain("Before")
+      expect(result).toContain("After")
+      expect(result).not.toContain("/command-inside-code")
+    })
+
+    it("should handle text without code blocks", () => {
+      // #given text without code blocks
+      const text = "Just regular text"
+
+      // #when removing code blocks
+      const result = removeCodeBlocks(text)
+
+      // #then text should remain unchanged
+      expect(result).toBe("Just regular text")
+    })
+  })
+
+  describe("parseSlashCommand", () => {
+    it("should parse simple command without args", () => {
+      // #given a simple slash command
+      const text = "/commit"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should extract command correctly
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("commit")
+      expect(result?.args).toBe("")
+    })
+
+    it("should parse command with arguments", () => {
+      // #given a slash command with arguments
+      const text = "/plan create a new feature for auth"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should extract command and args
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("plan")
+      expect(result?.args).toBe("create a new feature for auth")
+    })
+
+    it("should parse command with quoted arguments", () => {
+      // #given a slash command with quoted arguments
+      const text = '/execute "build the API"'
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should extract command and args
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("execute")
+      expect(result?.args).toBe('"build the API"')
+    })
+
+    it("should parse command with hyphen in name", () => {
+      // #given a slash command with hyphen
+      const text = "/frontend-template-creator project"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should extract full command name
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("frontend-template-creator")
+      expect(result?.args).toBe("project")
+    })
+
+    it("should return null for non-slash text", () => {
+      // #given text without slash
+      const text = "regular text"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should return null
+      expect(result).toBeNull()
+    })
+
+    it("should return null for slash not at start", () => {
+      // #given text with slash in middle
+      const text = "some text /command"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should return null (slash not at start)
+      expect(result).toBeNull()
+    })
+
+    it("should return null for just a slash", () => {
+      // #given just a slash
+      const text = "/"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should return null
+      expect(result).toBeNull()
+    })
+
+    it("should return null for slash followed by number", () => {
+      // #given slash followed by number
+      const text = "/123"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should return null (command must start with letter)
+      expect(result).toBeNull()
+    })
+
+    it("should handle whitespace before slash", () => {
+      // #given command with leading whitespace
+      const text = "  /commit"
+
+      // #when parsing
+      const result = parseSlashCommand(text)
+
+      // #then should parse after trimming
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("commit")
+    })
+  })
+
+  describe("isExcludedCommand", () => {
+    it("should exclude ralph-loop", () => {
+      // #given ralph-loop command
+      // #when checking exclusion
+      // #then should be excluded
+      expect(isExcludedCommand("ralph-loop")).toBe(true)
+    })
+
+    it("should exclude cancel-ralph", () => {
+      // #given cancel-ralph command
+      // #when checking exclusion
+      // #then should be excluded
+      expect(isExcludedCommand("cancel-ralph")).toBe(true)
+    })
+
+    it("should be case-insensitive for exclusion", () => {
+      // #given uppercase variants
+      // #when checking exclusion
+      // #then should still be excluded
+      expect(isExcludedCommand("RALPH-LOOP")).toBe(true)
+      expect(isExcludedCommand("Cancel-Ralph")).toBe(true)
+    })
+
+    it("should not exclude regular commands", () => {
+      // #given regular commands
+      // #when checking exclusion
+      // #then should not be excluded
+      expect(isExcludedCommand("commit")).toBe(false)
+      expect(isExcludedCommand("plan")).toBe(false)
+      expect(isExcludedCommand("execute")).toBe(false)
+    })
+  })
+
+  describe("detectSlashCommand", () => {
+    it("should detect slash command in plain text", () => {
+      // #given plain text with slash command
+      const text = "/commit fix typo"
+
+      // #when detecting
+      const result = detectSlashCommand(text)
+
+      // #then should detect
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("commit")
+      expect(result?.args).toBe("fix typo")
+    })
+
+    it("should NOT detect slash command inside code block", () => {
+      // #given slash command inside code block
+      const text = "```bash\n/command\n```"
+
+      // #when detecting
+      const result = detectSlashCommand(text)
+
+      // #then should not detect (only code block content)
+      expect(result).toBeNull()
+    })
+
+    it("should detect command when text has code blocks elsewhere", () => {
+      // #given slash command before code block
+      const text = "/commit fix\n```code```"
+
+      // #when detecting
+      const result = detectSlashCommand(text)
+
+      // #then should detect the command
+      expect(result).not.toBeNull()
+      expect(result?.command).toBe("commit")
+    })
+
+    it("should NOT detect excluded commands", () => {
+      // #given excluded command
+      const text = "/ralph-loop do something"
+
+      // #when detecting
+      const result = detectSlashCommand(text)
+
+      // #then should not detect
+      expect(result).toBeNull()
+    })
+
+    it("should return null for non-command text", () => {
+      // #given regular text
+      const text = "Just some regular text"
+
+      // #when detecting
+      const result = detectSlashCommand(text)
+
+      // #then should return null
+      expect(result).toBeNull()
+    })
+  })
+
+  describe("extractPromptText", () => {
+    it("should extract text from parts", () => {
+      // #given message parts
+      const parts = [
+        { type: "text", text: "Hello " },
+        { type: "tool_use", id: "123" },
+        { type: "text", text: "world" },
+      ]
+
+      // #when extracting
+      const result = extractPromptText(parts)
+
+      // #then should join text parts
+      expect(result).toBe("Hello  world")
+    })
+
+    it("should handle empty parts", () => {
+      // #given empty parts
+      const parts: Array<{ type: string; text?: string }> = []
+
+      // #when extracting
+      const result = extractPromptText(parts)
+
+      // #then should return empty string
+      expect(result).toBe("")
+    })
+
+    it("should handle parts without text", () => {
+      // #given parts without text content
+      const parts = [
+        { type: "tool_use", id: "123" },
+        { type: "tool_result", output: "result" },
+      ]
+
+      // #when extracting
+      const result = extractPromptText(parts)
+
+      // #then should return empty string
+      expect(result).toBe("")
+    })
+  })
+})

src/hooks/auto-slash-command/detector.ts

@@ -0,0 +1,65 @@
+import {
+  SLASH_COMMAND_PATTERN,
+  EXCLUDED_COMMANDS,
+} from "./constants"
+import type { ParsedSlashCommand } from "./types"
+
+const CODE_BLOCK_PATTERN = /```[\s\S]*?```/g
+
+export function removeCodeBlocks(text: string): string {
+  return text.replace(CODE_BLOCK_PATTERN, "")
+}
+
+export function parseSlashCommand(text: string): ParsedSlashCommand | null {
+  const trimmed = text.trim()
+
+  if (!trimmed.startsWith("/")) {
+    return null
+  }
+
+  const match = trimmed.match(SLASH_COMMAND_PATTERN)
+  if (!match) {
+    return null
+  }
+
+  const [raw, command, args] = match
+  return {
+    command: command.toLowerCase(),
+    args: args.trim(),
+    raw,
+  }
+}
+
+export function isExcludedCommand(command: string): boolean {
+  return EXCLUDED_COMMANDS.has(command.toLowerCase())
+}
+
+export function detectSlashCommand(text: string): ParsedSlashCommand | null {
+  const textWithoutCodeBlocks = removeCodeBlocks(text)
+  const trimmed = textWithoutCodeBlocks.trim()
+
+  if (!trimmed.startsWith("/")) {
+    return null
+  }
+
+  const parsed = parseSlashCommand(trimmed)
+
+  if (!parsed) {
+    return null
+  }
+
+  if (isExcludedCommand(parsed.command)) {
+    return null
+  }
+
+  return parsed
+}
+
+export function extractPromptText(
+  parts: Array<{ type: string; text?: string }>
+): string {
+  return parts
+    .filter((p) => p.type === "text")
+    .map((p) => p.text || "")
+    .join(" ")
+}