microsoft · sergio-sisternes-epam · Apr 20, 2026 · Apr 20, 2026
@@ -17,6 +17,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `apm install --ssh` / `--https` flags and `APM_GIT_PROTOCOL=ssh|https` env to pick the initial transport for shorthand dependencies (#778)
 - `apm install --allow-protocol-fallback` flag and `APM_ALLOW_PROTOCOL_FALLBACK=1` env as the migration escape hatch for cross-protocol fallback (#778)
 - Add APM Review Panel skill (`.github/skills/apm-review-panel/`) and four new specialist personas (`devx-ux-expert`, `supply-chain-security-expert`, `apm-ceo`, `oss-growth-hacker`) with auto-activating per-persona skills. Routes specialist findings through an APM CEO arbiter for strategic / breaking-change calls, with the OSS growth hacker side-channeling adoption insights via `WIP/growth-strategy.md`. Instrumentation per Handbook Ch. 9 (`The Instrumented Codebase`); PROSE-compliant (thin SKILL.md routers, persona detail lazy-loaded via markdown links, explicit boundaries per persona).
+- `apm view plugin@marketplace` displays marketplace plugin metadata (name, version, source, description) (#514)
+- `apm outdated` checks marketplace plugin refs and shows a "Source" column distinguishing marketplace vs git updates (#514)
+- `apm marketplace validate` command with schema validation and duplicate name detection (#514)
+- Ref immutability advisory: caches plugin-to-ref pins and warns when a previously pinned plugin's ref changes (#514)
+- Multi-marketplace shadow detection: warns when the same plugin name appears in multiple registered marketplaces (#514)
 
 ### Fixed
 

@@ -63,6 +63,21 @@ Marketplaces can declare a `metadata.pluginRoot` field to specify the base direc
 
 With `pluginRoot` set to `./plugins`, the source `"my-tool"` resolves to `owner/repo/plugins/my-tool`. Sources that already contain a path separator (e.g. `./custom/path`) are not affected by `pluginRoot`.
 
+### Versioned plugins
+
+Plugins can declare a `version` field and a `source.ref` that points to a specific Git tag or commit:
+
+```json
+{
+  "name": "code-review",
+  "description": "Automated code review agent",
+  "version": "2.1.0",
+  "source": { "type": "github", "repo": "acme/code-review-plugin", "ref": "v2.1.0" }
+}
+```
+
+The `version` field is informational (displayed by `apm view` and `apm outdated`). The `source.ref` determines which Git ref APM checks out during install.
+
 ## Register a marketplace
 
 ```bash
@@ -125,13 +140,32 @@ use `apm marketplace browse <name>` instead.
 Use the `NAME@MARKETPLACE` syntax to install a plugin from a specific marketplace:
 
 ```bash
+# Install using the source ref from the marketplace entry
 apm install code-review@acme-plugins
+
+# Install with a specific git ref override
+apm install code-review@acme-plugins#v2.0.0
+
+# Install from a specific branch
+apm install code-review@acme-plugins#main
 ```
 
-APM resolves the plugin name against the marketplace index, fetches the underlying Git repository, and installs it as a standard APM dependency. The resolved source appears in `apm.yml` and `apm.lock.yaml` just like any direct dependency.
+The `#` separator carries a raw git ref that overrides the `source.ref` from the marketplace entry. Without `#`, APM uses the ref defined in the marketplace manifest.
+
+APM resolves the plugin name against the marketplace index, fetches the underlying Git repository using the resolved ref, and installs it as a standard APM dependency. The resolved source appears in `apm.yml` and `apm.lock.yaml` just like any direct dependency.
 
 For full `apm install` options, see [CLI Commands](../../reference/cli-commands/).
 
+## View plugin details
+
+Show metadata for a marketplace plugin:
+
+```bash
+apm view code-review@acme-plugins
+```
+
+Displays the plugin's name, version, description, source, and tags.
+
 ## Provenance tracking
 
 Marketplace-resolved plugins are tracked in `apm.lock.yaml` with full provenance:
@@ -187,3 +221,50 @@ apm marketplace remove acme-plugins --yes
 ```
 
 Removing a marketplace does not uninstall plugins previously installed from it. Those plugins remain pinned in `apm.lock.yaml` to their resolved Git sources.
+
+## Validate a marketplace
+
+Check a marketplace manifest for schema errors and duplicate entries:
+
+```bash
+apm marketplace validate acme-plugins
+
+# Verbose output
+apm marketplace validate acme-plugins --verbose
+```
+
+Catches: missing required fields and duplicate plugin names (case-insensitive).
+
+:::note[Planned]
+The `--check-refs` flag will verify that source refs are reachable over the network. It is accepted but not yet implemented.
+:::
+
+For full option details, see [CLI Commands](../../reference/cli-commands/).
+
+## Security
+
+### Version immutability
+
+APM caches version-to-ref mappings in `~/.apm/cache/marketplace/version-pins.json`. On subsequent installs, APM compares the marketplace ref against the cached pin. If a version's ref has changed, APM warns:
+
+```
+WARNING: Version 2.0.0 of code-review@acme-plugins ref changed: was 'v2.0.0', now 'deadbeef'. This may indicate a ref swap attack.
+```
+
+This detects marketplace maintainers (or compromised accounts) silently pointing an existing version at different code.
+
+### Shadow detection
+
+When installing a marketplace plugin, APM checks all other registered marketplaces for plugins with the same name. A match produces a warning:
+
+```
+WARNING: Plugin 'code-review' also found in marketplace 'other-plugins'. Verify you are installing from the intended source.
+```
+
+Shadow detection runs automatically during install -- no configuration required.
+
+### Best practices
+
+- **Use commit SHAs as refs** -- tags and branches can be moved; commit SHAs cannot.
+- **Keep plugin names unique across marketplaces** -- avoids shadow warnings and reduces confusion.
+- **Review immutability warnings** -- a changed ref for an existing version is a strong signal of tampering.
@@ -81,7 +81,7 @@ apm install [PACKAGES...] [OPTIONS]
 ```
 
 **Arguments:**
-- `PACKAGES` - Optional APM packages to add and install. Accepts shorthand (`owner/repo`), HTTPS URLs, SSH URLs, FQDN shorthand (`host/owner/repo`), local filesystem paths (`./path`, `../path`, `/absolute/path`, `~/path`), or marketplace references (`NAME@MARKETPLACE`). All forms are normalized to canonical format in `apm.yml`.
+- `PACKAGES` - Optional APM packages to add and install. Accepts shorthand (`owner/repo`), HTTPS URLs, SSH URLs, FQDN shorthand (`host/owner/repo`), local filesystem paths (`./path`, `../path`, `/absolute/path`, `~/path`), or marketplace references (`NAME@MARKETPLACE[#ref]`). All forms are normalized to canonical format in `apm.yml`.
 
 **Options:**
 - `--runtime TEXT` - Target specific runtime only (copilot, codex, vscode)
@@ -191,6 +191,9 @@ apm install -g microsoft/apm-sample-package
 
 # Install a plugin from a registered marketplace
 apm install code-review@acme-plugins
+
+# Install a specific ref from a marketplace
+apm install code-review@acme-plugins#v2.0.0
 ```
 
 **Auto-Bootstrap Behavior:**
@@ -645,7 +648,7 @@ apm view PACKAGE [FIELD] [OPTIONS]
 ```
 
 **Arguments:**
-- `PACKAGE` - Package name, usually `owner/repo` or a short repo name
+- `PACKAGE` - Package name: `owner/repo`, short repo name, or `NAME@MARKETPLACE` for marketplace plugins
 - `FIELD` - Optional field selector. Supported value: `versions`
 
 **Options:**
@@ -662,6 +665,9 @@ apm view apm-sample-package
 # List remote tags and branches without cloning
 apm view microsoft/apm-sample-package versions
 
+# View available versions for a marketplace plugin
+apm view code-review@acme-plugins
+
 # Inspect a package from user scope
 apm view microsoft/apm-sample-package -g
 ```
@@ -671,6 +677,7 @@ apm view microsoft/apm-sample-package -g
 - Shows package name, version, description, source, install path, context files, workflows, and hooks
 - `versions` lists remote tags and branches without cloning the repository
 - `versions` does not require the package to be installed locally
+- `NAME@MARKETPLACE` syntax shows the marketplace plugin metadata (name, version, source, description, tags)
 
 ### `apm outdated` - Check locked dependencies for updates
 
@@ -704,8 +711,10 @@ apm outdated -j 8
 - Reads the current lockfile (`apm.lock.yaml`; legacy `apm.lock` is migrated automatically)
 - For tag-pinned deps: compares the locked semver tag against the latest available remote tag
 - For branch-pinned deps: compares the locked commit SHA against the remote branch tip SHA
+- For marketplace deps: compares the installed ref against the marketplace entry's current `source.ref`
 - For deps with no ref: compares against the default branch (main/master) tip SHA
-- Displays `Package`, `Current`, `Latest`, and `Status` columns
+- Displays `Package`, `Current`, `Latest`, `Status`, and `Source` columns
+- `Source` shows `marketplace: <name>` for marketplace-sourced deps
 - Status values are `up-to-date`, `outdated`, and `unknown`
 - Local dependencies and Artifactory dependencies are skipped
 
@@ -1084,6 +1093,30 @@ apm marketplace remove acme-plugins
 apm marketplace remove acme-plugins --yes
 ```
 
+#### `apm marketplace validate` - Validate a marketplace manifest
+
+Validate `marketplace.json` for schema errors and duplicate plugin names.
+
+```bash
+apm marketplace validate NAME [OPTIONS]
+```
+
+**Arguments:**
+- `NAME` - Name of the marketplace to validate
+
+**Options:**
+- `--check-refs` - Verify version refs are reachable (network). *Not yet implemented.*
+- `-v, --verbose` - Show detailed output
+
+**Examples:**
+```bash
+# Validate a marketplace
+apm marketplace validate acme-plugins
+
+# Verbose output
+apm marketplace validate acme-plugins --verbose
+```
+
 ### `apm search` - Search plugins in a marketplace
 
 Search for plugins by name or description within a specific marketplace.

@@ -57,7 +57,10 @@
 | `apm marketplace browse NAME` | Browse marketplace packages | -- |
 | `apm marketplace update [NAME]` | Update marketplace index | -- |
 | `apm marketplace remove NAME` | Remove a marketplace | `-y` skip confirm |
+| `apm marketplace validate NAME` | Validate marketplace manifest | `--check-refs`, `-v` |
 | `apm search QUERY@MARKETPLACE` | Search marketplace | `--limit N` |
+| `apm install NAME@MKT[#ref]` | Install from marketplace | Optional `#ref` override |
+| `apm view NAME@MARKETPLACE` | View marketplace plugin info | -- |
 
 ## MCP servers
 

@@ -179,6 +179,18 @@ dependencies:
 | Branch | `owner/repo#main` | Development -- tracks latest |
 | Commit SHA | `owner/repo#abc123d` | Maximum reproducibility |
 | No ref | `owner/repo` | Resolves default branch at install time |
+| Marketplace ref | `plugin@marketplace#ref` | Override marketplace source ref |
+
+## Marketplace ref override
+
+When installing from a marketplace, the `#` suffix overrides the `source.ref` from the marketplace entry:
+
+| Syntax | Meaning | Example |
+|--------|---------|---------|
+| `plugin@mkt` | Use marketplace source ref | `plugin@mkt` |
+| `plugin@mkt#v2.0.0` | Override with specific tag | `plugin@mkt#v2.0.0` |
+| `plugin@mkt#main` | Override with branch | `plugin@mkt#main` |
+| `plugin@mkt#abc123d` | Override with commit SHA | `plugin@mkt#abc123d` |
 
 ## What the lockfile pins
 

@@ -193,16 +193,20 @@ def _validate_and_add_packages_to_apm_yml(packages, dry_run=False, dev=False, lo
                 mkt_ref = None
 
             if mkt_ref is not None:
-                plugin_name, marketplace_name = mkt_ref
+                plugin_name, marketplace_name, version_spec = mkt_ref
                 try:
+                    warning_handler = None
                     if logger:
+                        warning_handler = lambda msg: logger.warning(msg)
                         logger.verbose_detail(
                             f"    Resolving {plugin_name}@{marketplace_name} via marketplace..."
                         )
                     canonical_str, resolved_plugin = resolve_marketplace_plugin(
                         plugin_name,
                         marketplace_name,
+                        version_spec=version_spec,
                         auth_resolver=auth_resolver,
+                        warning_handler=warning_handler,
                     )
                     if logger:
                         logger.verbose_detail(

@@ -368,6 +368,92 @@ def remove(name, yes, verbose):
         sys.exit(1)
 
 
+# ---------------------------------------------------------------------------
+# marketplace validate
+# ---------------------------------------------------------------------------
+
+
+@marketplace.command(help="Validate a marketplace manifest")
+@click.argument("name", required=True)
+@click.option(
+    "--check-refs", is_flag=True, help="Verify version refs are reachable (network)"
+)
+@click.option("--verbose", "-v", is_flag=True, help="Show detailed output")
+def validate(name, check_refs, verbose):
+    """Validate the manifest of a registered marketplace."""
+    logger = CommandLogger("marketplace-validate", verbose=verbose)
+    try:
+        from ..marketplace.client import fetch_marketplace
+        from ..marketplace.registry import get_marketplace_by_name
+        from ..marketplace.validator import validate_marketplace
+
+        source = get_marketplace_by_name(name)
+        logger.start(f"Validating marketplace '{name}'...", symbol="gear")
+
+        manifest = fetch_marketplace(source, force_refresh=True)
+
+        logger.progress(
+            f"Found {len(manifest.plugins)} plugins",
+            symbol="info",
+        )
+
+        # Verbose: per-plugin details
+        if verbose:
+            for p in manifest.plugins:
+                source_type = "dict" if isinstance(p.source, dict) else "string"
+                logger.verbose_detail(
+                    f"    {p.name}: source type: {source_type}"
+                )
+
+        # Run validation
+        results = validate_marketplace(manifest)
+
+        # Check-refs placeholder
+        if check_refs:
+            logger.warning(
+                "Ref checking not yet implemented -- skipping ref "
+                "reachability checks",
+                symbol="warning",
+            )
+
+        # Render results
+        passed = 0
+        warning_count = 0
+        error_count = 0
+        click.echo()
+        click.echo("Validation Results:")
+        for r in results:
+            if r.passed and not r.warnings:
+                logger.success(
+                    f"  {r.check_name}: all plugins valid", symbol="check"
+                )
+                passed += 1
+            elif r.warnings and not r.errors:
+                for w in r.warnings:
+                    logger.warning(f"  {r.check_name}: {w}", symbol="warning")
+                warning_count += len(r.warnings)
+            else:
+                for e in r.errors:
+                    logger.error(f"  {r.check_name}: {e}", symbol="error")
+                for w in r.warnings:
+                    logger.warning(f"  {r.check_name}: {w}", symbol="warning")
+                error_count += len(r.errors)
+                warning_count += len(r.warnings)
+
+        click.echo()
+        click.echo(
+            f"Summary: {passed} passed, {warning_count} warnings, "
+            f"{error_count} errors"
+        )
+
+        if error_count > 0:
+            sys.exit(1)
+
+    except Exception as e:
+        logger.error(f"Failed to validate marketplace: {e}")
+        sys.exit(1)
+
+
 # ---------------------------------------------------------------------------
 # Top-level search command (registered separately in cli.py)
 # ---------------------------------------------------------------------------
@@ -467,3 +553,4 @@ def search(expression, limit, verbose):
     except Exception as e:
         logger.error(f"Search failed: {e}")
         sys.exit(1)
+