feat(install): experimental Copilot canvas extensions

CHANGELOG.md

@@ -79,6 +79,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   faithfully reflects on-disk content across Copilot, Claude, and Gemini
   targets (including OS-specific `windows`/`linux`/`osx` hook keys). (by
   @harshitlarl, closes #316, #1700)
+- Experimental, Copilot-only `canvas` primitive: `.apm/extensions/<name>/extension.mjs` deploys to `.github/extensions/<name>/` on `apm install`/`apm pack`, gated by `apm experimental enable canvas` + `--trust-canvas-extensions` for dependencies. (by @sergio-sisternes-epam, #1689)
+- Experimental canvas: `apm install --global --trust-canvas-extensions` deploys dependency canvases to `~/.copilot/extensions/<name>/`; `apm uninstall --global` prunes them. (by @sergio-sisternes-epam, #1689)
+- Experimental canvas: package validation recognises canvas extensions (canvas-only packages valid, gated-executable warning); `apm audit` (text) lists deployed canvas bundles. (by @sergio-sisternes-epam, #1689)
 
 ### Changed
 

docs/astro.config.mjs

@@ -225,6 +225,7 @@ export default defineConfig({
 						{ label: 'GitHub Agentic Workflows', slug: 'integrations/gh-aw' },
 						{ label: 'Microsoft 365 Copilot Cowork (Experimental)', slug: 'integrations/copilot-cowork' },
 						{ label: 'GitHub Copilot App workflows (Experimental)', slug: 'integrations/copilot-app' },
+						{ label: 'Canvas extensions (Experimental)', slug: 'integrations/canvas' },
 						{ label: 'Hermes Agent (Experimental)', slug: 'integrations/hermes' },
 						{ label: 'AI runtime compatibility', slug: 'integrations/runtime-compatibility' },
 						{ label: 'GitHub rulesets', slug: 'integrations/github-rulesets' },

docs/src/content/docs/concepts/primitives-and-targets.md

@@ -68,6 +68,14 @@ Model Context Protocol servers declared as dependencies. APM writes the per-harn
 - Source: `apm.yml` -> `dependencies.mcp:`
 - Deep dive: [MCP servers](/apm/consumer/install-mcp-servers/)
 
+### Canvas extensions (experimental)
+
+GitHub Copilot CLI canvas extensions: a directory bundle whose entry file is `extension.mjs` (executable Node.js). Copilot-only. Behind the `canvas` experimental flag; dependency-provided canvases are blocked unless `--trust-canvas-extensions` is passed, because they are arbitrary executable code. Project scope deploys to `.github/extensions/`; `--global` deploys a dependency canvas to `~/.copilot/extensions/` (always requiring the trust flag).
+
+- Source: `.apm/extensions/<name>/extension.mjs`
+- Deploys to: `.github/extensions/<name>/` (project) or `~/.copilot/extensions/<name>/` (`--global`)
+- Deep dive: [Canvas extensions](/apm/integrations/canvas/)
+
 ## Target catalogue
 
 Each target is identified by a slug used in `apm.yml`'s `targets:` field and on the `--target` flag. The output directory is where APM writes deployed primitives. The "agent-skills" and "copilot-cowork" targets exist in the registry but are not end-user runtimes; they are covered separately in the experimental reference.
@@ -113,6 +121,7 @@ Rows are primitives, columns are harnesses. Cell legend:
 | commands | unsupported | native | compiled | unsupported | compiled | compiled | compiled | unsupported |
 | plugins | compiled | compiled | compiled | compiled | compiled | compiled | compiled | compiled |
 | MCP servers | native | native | native | native | native | native | native | native |
+| canvas (experimental) | gated | unsupported | unsupported | unsupported | unsupported | unsupported | unsupported | unsupported |
 
 How to read a cell:
 
@@ -122,6 +131,7 @@ How to read a cell:
 - `commands / copilot = unsupported` -- Copilot has no commands primitive; the same source `.prompt.md` reaches Copilot as a native prompt instead.
 - `plugins / *` -- APM unpacks the plugin at install time into the primitives in the rows above; routing then follows those rows.
 - `MCP servers / *` -- APM writes the harness's standard MCP config. Transitive MCP servers brought in by deep dependencies must be explicitly declared or trusted with `--trust-transitive-mcp` -- effectively `gated` for those, `native` for direct dependencies.
+- `canvas / copilot = gated` -- requires the `canvas` experimental flag; a canvas shipped by a dependency is executable code, so it stays blocked until you pass `--trust-canvas-extensions`. First-party canvases in your own package deploy at project scope once the flag is on. With `--global`, a dependency canvas deploys to `~/.copilot/extensions/` and always requires the trust flag (first-party global install is not supported). Every other harness is `unsupported`: a canvas is a Copilot CLI construct only.
 
 ## Where compiled context files land
 

docs/src/content/docs/enterprise/security.md

@@ -30,7 +30,7 @@ APM has no runtime footprint. Once `apm install` or `apm compile` completes, the
 
 - **No runtime component.** APM generates files then terminates. It does not run alongside your application.
 - **No network calls after install.** All network activity (git clone/fetch) occurs during dependency resolution. There are no callbacks, webhooks, or phone-home requests.
-- **No arbitrary code execution.** APM does not execute scripts from packages, evaluate expressions in templates, or run downloaded code.
+- **No arbitrary code execution.** APM does not execute scripts from packages, evaluate expressions in templates, or run downloaded code. (**Canvas exception:** the experimental `canvas` primitive deploys executable `extension.mjs` (Node.js) code to `.github/extensions/` or `~/.copilot/extensions/`; this surface is gated by both the `canvas` experimental flag and `--trust-canvas-extensions` for dependency-provided canvases. See [Canvas extensions](/apm/integrations/canvas/).)
 - **No access to application data.** APM never reads databases, API responses, application state, or user data.
 - **No persistent background processes.** APM does not install daemons, services, or scheduled tasks.
 - **No telemetry or data collection.** APM collects no usage data, analytics, or diagnostics. Nothing is transmitted to Microsoft or any third party.

docs/src/content/docs/integrations/canvas.md

@@ -0,0 +1,144 @@
+---
+title: "Canvas extensions (Experimental)"
+description: "Ship GitHub Copilot CLI canvas extensions through APM packages (experimental, Copilot-only)."
+sidebar:
+  order: 8
+  badge:
+    text: Experimental
+    variant: caution
+---
+
+:::caution[Experimental]
+This feature is behind the `canvas` experimental flag and is off by default.
+It is **Copilot-only**, and the CLI surface may change. Enable it explicitly
+before use.
+:::
+
+A **canvas** is a GitHub Copilot CLI extension: a directory bundle whose entry
+file is `extension.mjs` (executable Node.js), plus any sibling assets it needs.
+Copilot CLI discovers canvases in immediate subdirectories of
+`.github/extensions/<name>/` (project scope) and
+`~/.copilot/extensions/<name>/` (user scope). APM lets a package carry a canvas
+under `.apm/extensions/<name>/` and deploys it to the matching location at
+install time so the canvas is available in your Copilot session.
+
+Canvases are typically produced by the Copilot CLI `create-canvas` skill
+(scaffolds a working extension in `.github/extensions/`). This page covers
+how to ship one through an APM package.
+
+## Enable the feature
+
+```bash
+apm experimental enable canvas
+```
+
+Default APM behaviour never changes until the flag is enabled. With the flag
+off, `.apm/extensions/` is ignored entirely.
+
+## Author a canvas
+
+Place the bundle under your package's `.apm/` directory. The marker file is
+`extension.mjs`; a directory without it is ignored.
+
+```
+.apm/
+  extensions/
+    my-canvas/
+      extension.mjs     # required entry point (executable Node.js)
+      ui.js             # optional sibling assets
+      styles.css
+```
+
+The `<name>` segment becomes both the deploy directory and the extension id, so
+it is validated strictly: `[A-Za-z0-9._-]+`, no leading or trailing dot, no
+`..`, no path separators, and reserved device names are rejected.
+
+## Install
+
+```bash
+apm install --target copilot
+```
+
+APM deploys the bundle verbatim to `.github/extensions/my-canvas/`. The deploy
+is **atomic**: every file in the bundle is planned and validated first, and any
+unmanaged local collision skips the whole bundle (use `apm install --force` to
+overwrite) so you never end up with a half-updated executable extension.
+
+After a canvas deploys, start a new Copilot CLI session (exit and relaunch) --
+Copilot CLI discovers extensions at session start, so a freshly-deployed canvas
+is not picked up mid-session.
+
+## Trust gate for dependency canvases
+
+A canvas shipped by a **dependency** is arbitrary executable Node.js code. APM
+blocks dependency-provided canvases by default. To deploy them, opt in
+explicitly:
+
+```bash
+apm install --target copilot --trust-canvas-extensions
+```
+
+The trust gate is independent of the experimental flag:
+
+- The **experimental flag** decides whether the canvas primitive is processed at
+  all. It is a feature-availability gate, not a security gate.
+- The **`--trust-canvas-extensions` flag** decides whether *dependency*
+  canvases may deploy. Your own first-party canvas (in the root package you are
+  installing from) deploys freely once the flag is on; only dependency-provided
+  canvases need the trust flag.
+
+When a dependency canvas is blocked, APM prints a diagnostic naming the package,
+the canvas, the `extension.mjs` entry point, the deploy directory, and the
+opt-in flag. The same gate is enforced on offline bundle install
+(`apm install <bundle>`) and on `apm unpack`, so a vendored bundle cannot
+smuggle an executable canvas past trust.
+
+## Install globally (user scope)
+
+To make a canvas available in **every** Copilot session, install it globally so
+it lands in `~/.copilot/extensions/<name>/`:
+
+```bash
+apm install <package> --global --trust-canvas-extensions
+```
+
+Global canvas install is intentionally limited in this experimental release:
+
+- **Dependency-provided only.** Only a canvas shipped by a package you install
+  (the `--global` flow always treats the canvas as dependency-provided) deploys
+  globally, so APM records it in the user lockfile and `apm uninstall --global`
+  can prune it. A first-party root `.apm/extensions/` canvas is **not** deployed
+  at user scope -- package it and install it as a dependency instead.
+- **Trust is always required.** A global canvas has full-account blast radius,
+  so `--trust-canvas-extensions` is mandatory even though the project-scope
+  first-party path does not need it.
+- **Default `~/.copilot` only.** If `$COPILOT_HOME` is set to a non-default
+  location, APM refuses the global canvas install rather than deploy to a path
+  Copilot will not scan.
+
+`apm uninstall --global <package>` removes the deployed
+`~/.copilot/extensions/<name>/` files and prunes the empty directories.
+
+## Pack and uninstall
+
+`apm pack` preserves `.apm/extensions/` in the bundle, so a packed package keeps
+its canvas. `apm uninstall` removes the deployed `.github/extensions/<name>/`
+files and prunes the now-empty directories; uninstall is never gated by the
+experimental flag, so a previously-installed canvas can always be removed.
+
+## Scope and limitations
+
+- **Copilot-only.** A canvas is a Copilot CLI construct. Other targets
+  (`--target claude`, `cursor`, etc.) never receive it.
+- **Global install is dependency-only.** User-scope (`--global`) deployment to
+  `~/.copilot/extensions/` supports dependency-provided canvases (always
+  requiring `--trust-canvas-extensions`) and the default `~/.copilot` location
+  only; first-party root canvases deploy at project scope only.
+- **No compile/list surfacing yet.** Canvases are not yet shown by
+  `apm list`/`apm compile`; they are deployed at install only.
+- **No policy-file control yet.** Canvas trust is controlled only by the
+  `--trust-canvas-extensions` CLI flag; governing it via `apm-policy.yml` is
+  planned but not part of this experimental release.
+
+See the [primitives and targets](/apm/concepts/primitives-and-targets/) matrix
+for where the canvas primitive sits.

docs/src/content/docs/reference/cli/install.md

@@ -61,6 +61,7 @@ With no arguments it installs everything from `apm.yml`. With one or more `PACKA
 | `--audit <off\|warn\|block>` | (config/policy) | Run a content audit over the files this install deploys. `warn` records findings in the summary; `block` halts the install on critical findings. Overrides your `audit-on-install` config but cannot relax an org policy floor. Requires the `external-scanners` experimental flag. |
 | `--no-audit` | off | Disable the install-time audit for this invocation (equivalent to `--audit off`). Cannot relax an org policy `block` floor. |
 | `--trust-transitive-mcp` | off | Trust self-defined MCP servers shipped by transitive packages without re-declaring them in your `apm.yml`. |
+| `--trust-canvas-extensions` | off | Trust executable canvas extensions (`extension.mjs`) shipped by dependencies. Required for dependency-provided canvases; first-party canvases deploy without it. Requires the `canvas` experimental flag. |
 | `--allow-insecure` | off | Permit direct `http://` (non-TLS) dependencies. |
 | `--allow-insecure-host HOSTNAME` | unset | Permit transitive `http://` dependencies from `HOSTNAME`. Repeatable. |
 

docs/src/content/docs/reference/cli/pack.md

@@ -109,7 +109,7 @@ apm pack --archive --dry-run -v
 A Claude Code plugin directory under `--output`. Contains:
 
 - `plugin.json` -- schema-conformant manifest. Convention-dir keys are stripped because Claude Code auto-discovers them.
-- Plugin-native subdirs populated from your `.apm/` content and from installed dependencies: `agents/`, `skills/`, `commands/`, `instructions/`, `hooks/`.
+- Plugin-native subdirs populated from your `.apm/` content and from installed dependencies: `agents/`, `skills/`, `commands/`, `instructions/`, `hooks/`, `extensions/` (canvas extensions, when the `canvas` experimental flag is enabled).
 - A merged `hooks.json` when multiple sources contribute hooks.
 - `apm.lock.yaml` -- enriched copy with `pack:` metadata and a `bundle_files` map of per-file SHA-256 digests, used by `apm install` for install-time integrity verification.
 - `devDependencies` are excluded.

docs/src/content/docs/reference/cli/unpack.md

@@ -31,6 +31,7 @@ Extraction is **additive-only**: only files listed in the bundle's lockfile are
 | `--skip-verify` | off | Skip the bundle completeness check against the bundle's `apm.lock.yaml`. Useful for partial bundles. |
 | `--dry-run` | off | List files that would be unpacked without writing anything. |
 | `--force` | off | Deploy despite critical hidden-character findings from the security scan. Use only after independent verification. |
+| `--trust-canvas-extensions` | off | Trust executable canvas extensions (`extension.mjs`) in the bundle. Without this, canvas files are stripped during extraction. Requires the `canvas` experimental flag. |
 | `--verbose`, `-v` | off | Show per-file paths and full diagnostic context. |
 
 ## Examples

docs/src/content/docs/reference/experimental.md

@@ -175,6 +175,7 @@ apm experimental reset verbose-version
 | `marketplace-authoring`| Enable marketplace authoring commands (init, build, publish, etc.).              |
 | `registries`          | Enable REST-based APM package registries in `apm.yml`.                           |
 | `external-scanners`   | Ingest third-party SARIF scanners into `apm audit` (`--external`, including SkillSpector LLM mode and allowlisted `--external-args`), the `external.<name>.{llm,args}` config keys, and the `security.audit.scanners` policy block. See [External scanners](../integrations/external-scanners/). |
+| `canvas`              | Ship Copilot CLI canvas extensions (`.apm/extensions/<name>/extension.mjs`) through APM packages. Dependency-provided canvases additionally require `--trust-canvas-extensions`. See [Canvas extensions](../integrations/canvas/). |
 
 New flags are proposed via [CONTRIBUTING.md](https://github.com/microsoft/apm/blob/main/CONTRIBUTING.md#how-to-add-an-experimental-feature-flag) and graduate to default when stable. See the contributor recipe for the full lifecycle.
 See also: [Cowork integration](../integrations/copilot-cowork/).