Add Cursor plugin manifest and hook response compatibility

Enable native Cursor plugin discovery with a .cursor-plugin manifest, and make the SessionStart hook emit both Cursor and Claude response shapes so context injection works across both platforms. Document Cursor install usage in the README while keeping Claude-first wording.

Co-authored-by: Cursor <cursoragent@cursor.com>

.cursor-plugin/plugin.json

@@ -0,0 +1,18 @@
+{
+  "name": "superpowers",
+  "displayName": "Superpowers",
+  "description": "Core skills library: TDD, debugging, collaboration patterns, and proven techniques",
+  "version": "4.3.0",
+  "author": {
+    "name": "Jesse Vincent",
+    "email": "jesse@fsck.com"
+  },
+  "homepage": "https://github.com/obra/superpowers",
+  "repository": "https://github.com/obra/superpowers",
+  "license": "MIT",
+  "keywords": ["skills", "tdd", "debugging", "collaboration", "best-practices", "workflows"],
+  "skills": "./skills/",
+  "agents": "./agents/",
+  "commands": "./commands/",
+  "hooks": "./hooks/hooks.json"
+}

README.md

@@ -26,7 +26,8 @@ Thanks!
 
 ## Installation
 
-**Note:** Installation differs by platform. Claude Code has a built-in plugin system. Codex and OpenCode require manual setup.
+**Note:** Installation differs by platform. Claude Code or Cursor have built-in plugin marketplaces. Codex and OpenCode require manual setup.
+
 
 ### Claude Code (via Plugin Marketplace)
 
@@ -42,9 +43,17 @@ Then install the plugin from this marketplace:
 /plugin install superpowers@superpowers-marketplace
 ```
 
+### Cursor (via Plugin Marketplace)
+
+In Cursor Agent chat, install from marketplace:
+
+```text
+/plugin-add superpowers
+```
+
 ### Verify Installation
 
-Start a new session and ask Claude to help with something that would trigger a skill (e.g., "help me plan this feature" or "let's debug this issue"). Claude should automatically invoke the relevant superpowers skill.
+Start a new session in Claude or Cursor and ask for something that should trigger a skill (for example, "help me plan this feature" or "let's debug this issue"). The agent should automatically invoke the relevant superpowers skill.
 
 ### Codex
 

hooks/session-start.sh

@@ -32,13 +32,18 @@ escape_for_json() {
 
 using_superpowers_escaped=$(escape_for_json "$using_superpowers_content")
 warning_escaped=$(escape_for_json "$warning_message")
+session_context="<EXTREMELY_IMPORTANT>\nYou have superpowers.\n\n**Below is the full content of your 'superpowers:using-superpowers' skill - your introduction to using skills. For all other skills, use the 'Skill' tool:**\n\n${using_superpowers_escaped}\n\n${warning_escaped}\n</EXTREMELY_IMPORTANT>"
 
-# Output context injection as JSON
+# Output context injection as JSON.
+# Keep both shapes for compatibility:
+# - Cursor hooks expect additional_context.
+# - Claude hooks expect hookSpecificOutput.additionalContext.
 cat <<EOF
 {
+  "additional_context": "${session_context}",
   "hookSpecificOutput": {
     "hookEventName": "SessionStart",
-    "additionalContext": "<EXTREMELY_IMPORTANT>\nYou have superpowers.\n\n**Below is the full content of your 'superpowers:using-superpowers' skill - your introduction to using skills. For all other skills, use the 'Skill' tool:**\n\n${using_superpowers_escaped}\n\n${warning_escaped}\n</EXTREMELY_IMPORTANT>"
+    "additionalContext": "${session_context}"
   }
 }
 EOF