feat: add Copilot CLI tool mapping, docs, and install instructions

- Add references/copilot-tools.md with full tool equivalence table
- Add Copilot CLI to using-superpowers skill platform instructions
- Add marketplace install instructions to README
- Add changelog entry crediting @culinablaz for the hook fix

README.md

@@ -82,6 +82,13 @@ Fetch and follow instructions from https://raw.githubusercontent.com/obra/superp
 
 **Detailed docs:** [docs/README.opencode.md](docs/README.opencode.md)
 
+### GitHub Copilot CLI
+
+```bash
+copilot plugin marketplace add obra/superpowers-marketplace
+copilot plugin install superpowers@superpowers-marketplace
+```
+
 ### Gemini CLI
 
 ```bash

RELEASE-NOTES.md

@@ -1,5 +1,13 @@
 # Superpowers Release Notes
 
+## Unreleased
+
+### GitHub Copilot CLI Support
+
+- **SessionStart context injection** — Copilot CLI v1.0.11 added support for `additionalContext` in sessionStart hook output. The session-start hook now detects the `COPILOT_CLI` environment variable and emits the SDK-standard `{ "additionalContext": "..." }` format, giving Copilot CLI users the full superpowers bootstrap at session start. (Original fix by @culinablaz in PR #910)
+- **Tool mapping** — added `references/copilot-tools.md` with the full Claude Code to Copilot CLI tool equivalence table
+- **Skill and README updates** — added Copilot CLI to the `using-superpowers` skill's platform instructions and README installation section
+
 ## v5.0.6 (2026-03-24)
 
 ### Inline Self-Review Replaces Subagent Review Loops

skills/using-superpowers/SKILL.md

@@ -29,13 +29,15 @@ If CLAUDE.md, GEMINI.md, or AGENTS.md says "don't use TDD" and a skill says "alw
 
 **In Claude Code:** Use the `Skill` tool. When you invoke a skill, its content is loaded and presented to you—follow it directly. Never use the Read tool on skill files.
 
+**In Copilot CLI:** Use the `skill` tool. Skills are auto-discovered from installed plugins. The `skill` tool works the same as Claude Code's `Skill` tool.
+
 **In Gemini CLI:** Skills activate via the `activate_skill` tool. Gemini loads skill metadata at session start and activates the full content on demand.
 
 **In other environments:** Check your platform's documentation for how skills are loaded.
 
 ## Platform Adaptation
 
-Skills use Claude Code tool names. Non-CC platforms: see `references/codex-tools.md` (Codex) for tool equivalents. Gemini CLI users get the tool mapping loaded automatically via GEMINI.md.
+Skills use Claude Code tool names. Non-CC platforms: see `references/copilot-tools.md` (Copilot CLI), `references/codex-tools.md` (Codex) for tool equivalents. Gemini CLI users get the tool mapping loaded automatically via GEMINI.md.
 
 # Using Skills
 

skills/using-superpowers/references/copilot-tools.md

@@ -0,0 +1,52 @@
+# Copilot CLI Tool Mapping
+
+Skills use Claude Code tool names. When you encounter these in a skill, use your platform equivalent:
+
+| Skill references | Copilot CLI equivalent |
+|-----------------|----------------------|
+| `Read` (file reading) | `view` |
+| `Write` (file creation) | `create` |
+| `Edit` (file editing) | `edit` |
+| `Bash` (run commands) | `bash` |
+| `Grep` (search file content) | `grep` |
+| `Glob` (search files by name) | `glob` |
+| `Skill` tool (invoke a skill) | `skill` |
+| `WebFetch` | `web_fetch` |
+| `Task` tool (dispatch subagent) | `task` (see [Agent types](#agent-types)) |
+| Multiple `Task` calls (parallel) | Multiple `task` calls |
+| Task status/output | `read_agent`, `list_agents` |
+| `TodoWrite` (task tracking) | `sql` with built-in `todos` table |
+| `WebSearch` | No equivalent — use `web_fetch` with a search engine URL |
+| `EnterPlanMode` / `ExitPlanMode` | No equivalent — stay in the main session |
+
+## Agent types
+
+Copilot CLI's `task` tool accepts an `agent_type` parameter:
+
+| Claude Code agent | Copilot CLI equivalent |
+|-------------------|----------------------|
+| `general-purpose` | `"general-purpose"` |
+| `Explore` | `"explore"` |
+| Named plugin agents (e.g. `superpowers:code-reviewer`) | Discovered automatically from installed plugins |
+
+## Async shell sessions
+
+Copilot CLI supports persistent async shell sessions, which have no direct Claude Code equivalent:
+
+| Tool | Purpose |
+|------|---------|
+| `bash` with `async: true` | Start a long-running command in the background |
+| `write_bash` | Send input to a running async session |
+| `read_bash` | Read output from an async session |
+| `stop_bash` | Terminate an async session |
+| `list_bash` | List all active shell sessions |
+
+## Additional Copilot CLI tools
+
+| Tool | Purpose |
+|------|---------|
+| `store_memory` | Persist facts about the codebase for future sessions |
+| `report_intent` | Update the UI status line with current intent |
+| `sql` | Query the session's SQLite database (todos, metadata) |
+| `fetch_copilot_cli_documentation` | Look up Copilot CLI documentation |
+| GitHub MCP tools (`github-mcp-server-*`) | Native GitHub API access (issues, PRs, code search) |