diff --git a/cmd/enclave/tool_imports.go b/cmd/enclave/tool_imports.go
index aa046599..27028c96 100644
--- a/cmd/enclave/tool_imports.go
+++ b/cmd/enclave/tool_imports.go
@@ -13,5 +13,6 @@ package main
 import (
 	_ "enclave/extensions/tools/claude/go"
 	_ "enclave/extensions/tools/codex/go"
+	_ "enclave/extensions/tools/copilot/go"
 	_ "enclave/extensions/tools/opencode/go"
 )
diff --git a/docs/configuration.md b/docs/configuration.md
index e9c61c9e..c1e066a1 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -295,6 +295,7 @@ Common settings paths:
 |------|--------------------|
 | claude | `settings.json` |
 | codex | `config.toml` |
+| copilot | `settings.json` |
 | mistral-vibe | `config.toml` |
 | opencode | `opencode.json` |
 | pi | `agent/settings.json` |
diff --git a/docs/tools.md b/docs/tools.md
index 9730a9c1..08811407 100644
--- a/docs/tools.md
+++ b/docs/tools.md
@@ -13,6 +13,7 @@ Built-in tool profiles:
 |------|-------------|
 | `claude` | [Claude Code](https://www.anthropic.com/claude-code) (Anthropic) |
 | `codex` | [Codex CLI](https://github.com/openai/codex) (OpenAI) |
+| `copilot` | [GitHub Copilot CLI](https://github.com/features/copilot/cli) (GitHub) |
 | `mistral-vibe` | [Mistral Vibe CLI](https://github.com/mistralai/mistral-vibe) (opt-in/experimental) |
 | `opencode` | [OpenCode](https://opencode.ai/) |
 | `pi` | [Pi](https://github.com/earendil-works/pi) |
diff --git a/extensions/tools/copilot/README.md b/extensions/tools/copilot/README.md
new file mode 100644
index 00000000..b77c3da0
--- /dev/null
+++ b/extensions/tools/copilot/README.md
@@ -0,0 +1,112 @@
+# Copilot CLI
+
+GitHub Copilot CLI is the command-line coding assistant for GitHub Copilot.
+
+## Configuration
+
+- **Command**: `copilot --disable-builtin-mcps`
+- **YOLO flag**: `--yolo` (enabled by default)
+- **Config directory**: `~/.copilot`
+- **Settings file**: `~/.copilot/settings.json`
+- **Skills directory**: `~/.copilot/skills`
+
+The extension also passes through selected project-level Copilot configuration:
+`agents/`, `copilot-instructions.md`, `extensions/`, `hooks/`, `instructions/`,
+`lsp-config.json`, `mcp-config.json`, `providers.json`, `settings.json`, and
+`skills/`.
+
+## Authentication
+
+| Variable | Purpose |
+|----------|---------|
+| `COPILOT_GITHUB_TOKEN` | GitHub token injected by the network gateway |
+
+The provider declares `~/.copilot/config.json` as its auth file. Enclave uses
+its presence to detect an existing auth session and includes it in auth
+import/export. See [Authentication & Secrets](../../../docs/auth.md).
+
+The gateway sends the declared token as a Bearer authorization header to
+`api.github.com` and `*.githubcopilot.com`.
+
+### Recommended: fine-grained PAT via `COPILOT_GITHUB_TOKEN`
+
+Prefer `COPILOT_GITHUB_TOKEN` with a fine-grained personal access token that
+only grants the **Copilot Requests** permission. This is the minimum Copilot CLI
+needs and the approach recommended by the Copilot CLI maintainers
+([github/copilot-cli#953](https://github.com/github/copilot-cli/issues/953)).
+
+### OAuth login (`/login`) grants broad scopes
+
+> **Warning:** The device-code and browser OAuth login (`/login`) issues a token
+> with far more scopes than Copilot needs. Observed token scopes:
+> `codespace`, `gist`, `read:org`, `read:user`, `repo` (read and write), and
+> `write:plugin_gateway_connections`.
+
+A token with `repo` write access can read and modify private repositories, so
+anyone who obtains the stored OAuth credentials (under
+`~/.local/state/enclave/tools/copilot/`) can act on your GitHub account beyond
+Copilot. Use OAuth only when you accept this risk; otherwise use a fine-grained
+PAT as described above.
+
+## Memory and Skills
+
+Copilot Memory is **disabled by default** (`"memory": false` in the settings
+template). Copilot stores memories on GitHub's servers, not in a local memory
+directory. Account-scoped memories can be retrieved by later sessions in other
+projects, other Enclave state roots, or Copilot outside Enclave. This can expose
+project information across those boundaries and let one project's agent
+influence another through shared memories. In YOLO mode, an agent can store
+memories without a confirmation prompt.
+
+Enclave's per-project memory isolation applies to local files and cannot isolate
+this server-side memory. The extension therefore does not declare a native
+memory directory or memory-disable arguments; `--no-memory` is not a control for
+Copilot's server-side memory.
+
+If you accept this cross-project sharing, run `/memory on` inside a Copilot
+session to enable it, or `/memory off` to disable it again. When an Enclave config
+override or patch is active, the changed setting carries forward in that
+project's config store. See [Tool Config Patches](../../../docs/configuration.md#tool-config-patches)
+for settings persistence and precedence.
+
+For a persistent opt-in, add `"memory": true` to a
+[settings patch](../../../docs/configuration.md#tool-config-patches), for example
+`~/.config/enclave/patches/copilot/settings.json` on Linux:
+
+```json
+{
+  "memory": true
+}
+```
+
+This global patch enables memory for all projects unless overridden by a
+project-specific setting. It does not make the stored memories project-scoped.
+
+The extension's `enclave-help` skill is installed alongside managed skills in
+`~/.copilot/skills`.
+
+## Network Access
+
+The Copilot service domains are `api.github.com` and `*.githubcopilot.com`.
+The DNS allowlist also includes the common GitHub, npm, PyPI, Go, CDN, and
+TLS/OCSP infrastructure fragments used by Enclave.
+
+## Settings
+
+The default settings template sets `remoteExport` and `autoUpdate` to `false`,
+`includeCoAuthoredBy`, `storeTokenPlaintext`, and `memory` to `false`,
+`logLevel` to `default`, and `model` to `auto`. See [Memory and Skills](#memory-and-skills)
+before enabling memory.
+
+## Files
+
+| File | Purpose |
+|------|---------|
+| `spec.yaml` | Extension manifest (launch behavior, settings, credentials, network, and provider auth) |
+| `install.sh` | Installs `@github/copilot` and its `copilot` command |
+| `check-update.sh` | Returns the latest npm package version for update probes |
+| `gateway-allowlist.conf` | DNS allowlist for network isolation |
+| `templates/settings.json` | Default Copilot settings template |
+| `entrypoint.d/setup.sh` | Creates `~/.copilot` and sets `COPILOT_HOME` |
+| `skills/enclave-help/SKILL.md` | Bundled skill for answering questions from Enclave's documentation |
+| `go/handler.go` | Registers the Copilot tool handler |
\ No newline at end of file
diff --git a/extensions/tools/copilot/check-update.sh b/extensions/tools/copilot/check-update.sh
new file mode 100644
index 00000000..22562746
--- /dev/null
+++ b/extensions/tools/copilot/check-update.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Copyright (C) 2026 Dirk Fauth and others.
+#
+# This program and the accompanying materials are made available under the
+# terms of the MIT License, which is available in the project root.
+#
+# SPDX-License-Identifier: MIT
+
+set -euo pipefail
+
+npm view @github/copilot@latest version
diff --git a/extensions/tools/copilot/entrypoint.d/setup.sh b/extensions/tools/copilot/entrypoint.d/setup.sh
new file mode 100644
index 00000000..523c6abc
--- /dev/null
+++ b/extensions/tools/copilot/entrypoint.d/setup.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+# Copyright (C) 2026 Dirk Fauth and others.
+#
+# This program and the accompanying materials are made available under the
+# terms of the MIT License, which is available in the project root.
+#
+# SPDX-License-Identifier: MIT
+# shellcheck shell=bash
+
+# Copilot extension setup
+export COPILOT_HOME="$HOME/.copilot"
+mkdir -p "$COPILOT_HOME"
+
+# In yolo mode, remember the project workspace as trusted for future sessions.
+if [ "${ENCLAVE_YOLO:-}" = "1" ] && [ -n "${PROJECT_DIR:-}" ] && command -v jq >/dev/null 2>&1; then
+	_config="$COPILOT_HOME/config.json"
+	if [ -f "$_config" ]; then
+		# Copilot rewrites config.json as JSONC (leading // comments); strip them for jq.
+		_updated="$(grep -v '^[[:space:]]*//' "$_config" | jq --arg dir "$PROJECT_DIR" \
+			'.trustedFolders = (((.trustedFolders // []) + [$dir]) | unique)' \
+			2>/dev/null)" && printf '%s\n' "$_updated" > "$_config"
+	else
+		jq -n --arg dir "$PROJECT_DIR" '{trustedFolders:[$dir]}' > "$_config"
+	fi
+	unset _config _updated
+fi
diff --git a/extensions/tools/copilot/gateway-allowlist.conf b/extensions/tools/copilot/gateway-allowlist.conf
new file mode 100644
index 00000000..12f4c99c
--- /dev/null
+++ b/extensions/tools/copilot/gateway-allowlist.conf
@@ -0,0 +1,19 @@
+# Copyright (C) 2026 Dirk Fauth and others.
+#
+# This program and the accompanying materials are made available under the
+# terms of the MIT License, which is available in the project root.
+#
+# SPDX-License-Identifier: MIT
+
+# Enclave DNS Allowlist Configuration - Copilot
+no-resolv
+no-poll
+address=/#/
+
+# Common Infrastructure
+conf-file=/etc/dnsmasq.allowlists/fragments/github.conf
+conf-file=/etc/dnsmasq.allowlists/fragments/npm.conf
+conf-file=/etc/dnsmasq.allowlists/fragments/pypi.conf
+conf-file=/etc/dnsmasq.allowlists/fragments/go.conf
+conf-file=/etc/dnsmasq.allowlists/fragments/cdn.conf
+conf-file=/etc/dnsmasq.allowlists/fragments/tls.conf
diff --git a/extensions/tools/copilot/go/handler.go b/extensions/tools/copilot/go/handler.go
new file mode 100644
index 00000000..e0c7b8e4
--- /dev/null
+++ b/extensions/tools/copilot/go/handler.go
@@ -0,0 +1,18 @@
+// Copyright (C) 2026 Dirk Fauth and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the MIT License, which is available in the project root.
+//
+// SPDX-License-Identifier: MIT
+
+package copilot
+
+import "enclave/internal/tools"
+
+func init() {
+	tools.RegisterHandler("copilot", Handler{})
+}
+
+type Handler struct {
+	tools.BaseHandler
+}
diff --git a/extensions/tools/copilot/install.sh b/extensions/tools/copilot/install.sh
new file mode 100644
index 00000000..3966efc4
--- /dev/null
+++ b/extensions/tools/copilot/install.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+# Copyright (C) 2026 Dirk Fauth and others.
+#
+# This program and the accompanying materials are made available under the
+# terms of the MIT License, which is available in the project root.
+#
+# SPDX-License-Identifier: MIT
+
+set -e
+
+enclave-install-npm-tool @github/copilot@latest copilot Copilot
diff --git a/extensions/tools/copilot/skills/enclave-help/SKILL.md b/extensions/tools/copilot/skills/enclave-help/SKILL.md
new file mode 100644
index 00000000..6f350d92
--- /dev/null
+++ b/extensions/tools/copilot/skills/enclave-help/SKILL.md
@@ -0,0 +1,44 @@
+---
+name: enclave-help
+description: Answer questions about Enclave by reading the bundled documentation
+---
+
+# Enclave Help
+
+Answer the user's question about Enclave by reading the relevant documentation
+files bundled at `/usr/share/doc/enclave/`.
+
+## Important context
+
+You are running inside an Enclave container. Host-global configuration
+(e.g. `~/.config/enclave/config.json`, network policies, secrets) lives on the
+host filesystem and is not directly editable from inside the container.
+When a question involves host-side configuration changes, explain what the
+user needs to do on the host or via the `enclave` CLI rather than
+attempting in-container file edits.
+
+## Documentation index
+
+| Path | Topic |
+|------|-------|
+| `docs/README.md` | Documentation index |
+| `docs/ARCHITECTURE.md` | Detailed architecture with diagrams |
+| `docs/cli-reference.md` | CLI flags and options |
+| `docs/configuration.md` | Config files and settings |
+| `docs/networking.md` | Network isolation and gateway |
+| `docs/auth.md` | Authentication and API keys |
+| `docs/persistence.md` | Persistent stores and session data |
+| `docs/tools.md` | Supported agent tools |
+| `docs/extensions/` | Extension system (adding tools, features) |
+| `docs/runtime/` | Runtime behavior (stores, auth sync, network flow) |
+| `docs/security/` | Security model and host hardening |
+| `extensions/tools/<tool>/README.md` | Per-tool documentation |
+| `extensions/features/<feature>/README.md` | Per-feature documentation |
+
+All paths are relative to `/usr/share/doc/enclave/`.
+
+## Steps
+
+1. Read the doc(s) most relevant to the user's question.
+2. Synthesize a clear, concise answer from what you find.
+3. If the docs don't cover the topic, say so explicitly.
\ No newline at end of file
diff --git a/extensions/tools/copilot/spec.yaml b/extensions/tools/copilot/spec.yaml
new file mode 100644
index 00000000..b831668e
--- /dev/null
+++ b/extensions/tools/copilot/spec.yaml
@@ -0,0 +1,71 @@
+# Copyright (C) 2026 Dirk Fauth and others.
+#
+# This program and the accompanying materials are made available under the
+# terms of the MIT License, which is available in the project root.
+#
+# SPDX-License-Identifier: MIT
+
+schemaVersion: "1"
+kind: sandbox
+name: copilot
+displayName: Copilot CLI
+description: Copilot CLI
+
+sandbox:
+  entrypoint: { run: [copilot, --disable-builtin-mcps, --disable-client-telemetry] }
+  configDir: .copilot
+  statePaths: [
+    config.json,
+    session-state/,
+    sidebar-sessions-state/,
+    command-history-state*,
+    session-store.db*,
+    permissions-config.json,
+    mcp-oauth-config/,
+    mcp-secrets/,
+    installed-plugins/,
+    plugin-data/
+  ]
+  qemuMinMemoryMiB: 4096
+  skillsDir: .copilot/skills
+  settingsFile: copilot-settings.json
+  settingsTarget: .copilot/settings.json
+  yoloFlag: --yolo
+  yoloEnabled: true
+  continueArgs: [--continue]
+  resumeArgs: [--resume]
+  passthroughPaths: [
+    agents/,
+    copilot-instructions.md,
+    extensions/,
+    hooks/,
+    instructions/,
+    lsp-config.json,
+    mcp-config.json,
+    providers.json,
+    settings.json,
+    skills/]
+
+credentials:
+  sources:
+    copilot-github-token:
+      env: [COPILOT_GITHUB_TOKEN]
+      placeholder:
+        prefix: github_pat_
+        random: { encoding: alphanumeric, length: 82 }
+
+network:
+  serviceDomains:
+    api.github.com: copilot-github-token
+    "*.githubcopilot.com": copilot-github-token
+  serviceAuth:
+    copilot-github-token: { headerName: Authorization, valueFormat: "Bearer %s" }
+
+providers:
+  - name: github
+    credentials: [copilot-github-token]
+    authFiles: [config.json]
+    authSession:
+      mode: any
+      checks:
+        - { file: config.json, type: file_exists }
diff --git a/extensions/tools/copilot/templates/settings.json b/extensions/tools/copilot/templates/settings.json
new file mode 100644
index 00000000..5c6e8545
--- /dev/null
+++ b/extensions/tools/copilot/templates/settings.json
@@ -0,0 +1,9 @@
+{
+  "remoteExport": false,
+  "autoUpdate": false,
+  "logLevel": "default",
+  "includeCoAuthoredBy": false,
+  "storeTokenPlaintext": false,
+  "model": "auto",
+  "memory": false
+}
diff --git a/internal/config/testdata/golden/tool-copilot.json b/internal/config/testdata/golden/tool-copilot.json
new file mode 100644
index 00000000..3ac1f482
--- /dev/null
+++ b/internal/config/testdata/golden/tool-copilot.json
@@ -0,0 +1,88 @@
+{
+  "name": "copilot",
+  "command": "copilot --disable-builtin-mcps --disable-client-telemetry",
+  "continue_args": [
+    "--continue"
+  ],
+  "resume_args": [
+    "--resume"
+  ],
+  "yolo_flag": "--yolo",
+  "yolo_enabled": true,
+  "config_dir": ".copilot",
+  "skills_dir": ".copilot/skills",
+  "state_paths": [
+    "config.json",
+    "session-state/",
+    "sidebar-sessions-state/",
+    "command-history-state*",
+    "session-store.db*",
+    "permissions-config.json",
+    "mcp-oauth-config/",
+    "mcp-secrets/",
+    "installed-plugins/",
+    "plugin-data/"
+  ],
+  "settings_file": "copilot-settings.json",
+  "settings_target": ".copilot/settings.json",
+  "passthrough_paths": [
+    "agents/",
+    "copilot-instructions.md",
+    "extensions/",
+    "hooks/",
+    "instructions/",
+    "lsp-config.json",
+    "mcp-config.json",
+    "providers.json",
+    "settings.json",
+    "skills/"
+  ],
+  "qemu_min_memory_mib": 4096,
+  "providers": [
+    {
+      "name": "github",
+      "credential_secrets": [
+        "copilot-github-token"
+      ],
+      "auth_files": [
+        "config.json"
+      ],
+      "auth_session": {
+        "mode": "any",
+        "checks": [
+          {
+            "file": "config.json",
+            "type": "file_exists"
+          }
+        ]
+      }
+    }
+  ],
+  "secrets": {
+    "copilot-github-token": {
+      "env_vars": [
+        "COPILOT_GITHUB_TOKEN"
+      ],
+      "release": {
+        "http": {
+          "hosts": [
+            "*.githubcopilot.com",
+            "api.github.com"
+          ],
+          "header": "authorization",
+          "format": "Bearer %s"
+        }
+      },
+      "placeholder": {
+        "prefix": "github_pat_",
+        "random": {
+          "encoding": "alphanumeric",
+          "length": 82
+        }
+      }
+    }
+  },
+  "host_config_dir": "",
+  "host_credentials_file": "",
+  "host_oauth_json": ""
+}
diff --git a/internal/config/testdata/golden/tool-ext-copilot.json b/internal/config/testdata/golden/tool-ext-copilot.json
new file mode 100644
index 00000000..9f04d45c
--- /dev/null
+++ b/internal/config/testdata/golden/tool-ext-copilot.json
@@ -0,0 +1,32 @@
+{
+  "type": "sandbox",
+  "name": "copilot",
+  "display_name": "Copilot CLI",
+  "description": "Copilot CLI",
+  "default_included": true,
+  "priority": 100,
+  "secrets": {
+    "copilot-github-token": {
+      "env_vars": [
+        "COPILOT_GITHUB_TOKEN"
+      ],
+      "release": {
+        "http": {
+          "hosts": [
+            "*.githubcopilot.com",
+            "api.github.com"
+          ],
+          "header": "authorization",
+          "format": "Bearer %s"
+        }
+      },
+      "placeholder": {
+        "prefix": "github_pat_",
+        "random": {
+          "encoding": "alphanumeric",
+          "length": 82
+        }
+      }
+    }
+  }
+}