feat(archive): add server-side archive downloads

.agents/skills/use-ocis-cli/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: use-ocis-cli
-description: Safely operate oCIS servers through the installed ocis command-line client. Use when an AI agent is asked to inspect, list, search, transfer, synchronize, share, restore, inspect activity history, manage notifications, or administer files, Spaces, shares, users, or groups in oCIS. Do not use for developing the ocis-cli source code.
+description: Safely operate oCIS servers through the installed ocis command-line client. Use when an AI agent is asked to inspect, list, search, transfer, archive, synchronize, share, restore, inspect activity history, manage notifications, or administer files, Spaces, shares, users, or groups in oCIS. Do not use for developing the ocis-cli source code.
 ---
 
 # Use oCIS CLI
@@ -52,6 +52,9 @@ protocol-level work.
 ## Choose the operation
 
 - Use `upload` or `download` for a one-time transfer.
+- Use `archive download` when the user wants the server to package one or more
+  remote resources into a single ZIP or TAR file. Check `archive formats` and
+  run with `--dry-run` before a broad archive download.
 - Use `sync push`, `sync pull`, or `sync bidirectional` for directory trees that
   should be reconciled. Run a sync with `--dry-run` first.
 - Use `share received` or `share overview` to inspect shares. Never accept a

.agents/skills/use-ocis-cli/references/commands.md

@@ -53,6 +53,8 @@ same command.
 | `rm, remove` | Move a remote resource to trash unless the selected operation states otherwise. |
 | `upload` | Transfer a local file or directory to oCIS. |
 | `download` | Transfer a remote file or directory to the local filesystem. |
+| `archive download` | Ask the server to package selected remote resources into one local ZIP or TAR archive. |
+| `archive formats` | List archive formats and source limits advertised by the server. |
 | `du` | Summarize logical remote file sizes. |
 | `search, find` | Search remote files and directories. |
 | `batch` | Execute reviewed file operations supplied as JSONL. |

.claude/skills/use-ocis-cli/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: use-ocis-cli
-description: Safely operate oCIS servers through the installed ocis command-line client. Use when an AI agent is asked to inspect, list, search, transfer, synchronize, share, restore, inspect activity history, manage notifications, or administer files, Spaces, shares, users, or groups in oCIS. Do not use for developing the ocis-cli source code.
+description: Safely operate oCIS servers through the installed ocis command-line client. Use when an AI agent is asked to inspect, list, search, transfer, archive, synchronize, share, restore, inspect activity history, manage notifications, or administer files, Spaces, shares, users, or groups in oCIS. Do not use for developing the ocis-cli source code.
 ---
 
 # Use oCIS CLI
@@ -52,6 +52,9 @@ protocol-level work.
 ## Choose the operation
 
 - Use `upload` or `download` for a one-time transfer.
+- Use `archive download` when the user wants the server to package one or more
+  remote resources into a single ZIP or TAR file. Check `archive formats` and
+  run with `--dry-run` before a broad archive download.
 - Use `sync push`, `sync pull`, or `sync bidirectional` for directory trees that
   should be reconciled. Run a sync with `--dry-run` first.
 - Use `share received` or `share overview` to inspect shares. Never accept a

.claude/skills/use-ocis-cli/references/commands.md

@@ -53,6 +53,8 @@ same command.
 | `rm, remove` | Move a remote resource to trash unless the selected operation states otherwise. |
 | `upload` | Transfer a local file or directory to oCIS. |
 | `download` | Transfer a remote file or directory to the local filesystem. |
+| `archive download` | Ask the server to package selected remote resources into one local ZIP or TAR archive. |
+| `archive formats` | List archive formats and source limits advertised by the server. |
 | `du` | Summarize logical remote file sizes. |
 | `search, find` | Search remote files and directories. |
 | `batch` | Execute reviewed file operations supplied as JSONL. |

ARCHITECTURE.md

@@ -13,6 +13,7 @@ internal/
   command/            Cobra command tree and input validation
   app/                application use-case orchestration
   apperror/           stable error categories and exit-code mapping
+  archiver/            authenticated archive-download protocol client
   auth/               OIDC protocol implementation
   config/             persisted profile model and atomic storage
   credentials/        OS credential-service adapter
@@ -69,6 +70,9 @@ without starting a subprocess.
   contains shared application wiring.
 - `internal/apperror`: classify usage, authentication, not-found, and conflict
   errors without coupling application services to Cobra.
+- `internal/archiver`: validate same-origin server-advertised archive endpoints,
+  stream authenticated ZIP or TAR responses, and verify completed archives
+  before the application atomically installs them at a local destination.
 - `internal/activities`: query account-wide or resource-scoped activity
   history through the bounded oCIS Graph extension, preserving the localized
   message template and structured variables returned by the server.
@@ -143,7 +147,7 @@ without starting a subprocess.
   authentication headers, metadata and checksum response mapping, and safe
   scalar custom-property `PROPFIND`/`PROPPATCH` operations.
 
-Protocol-specific behavior belongs in dedicated `internal/activities`, `internal/auth`,
+Protocol-specific behavior belongs in dedicated `internal/activities`, `internal/archiver`, `internal/auth`,
 `internal/eventstream`, `internal/federation`, `internal/graph`, `internal/notifications`,
 `internal/search`, `internal/sharing`, `internal/trash`, `internal/versions`,
 and `internal/webdav` adapters. Recursive local/remote

Makefile

@@ -43,7 +43,7 @@ check: fmt
 
 coverage:
 	go run ./tools/covercheck -min $(COVERAGE_MIN) \
-		activities app auth eventstream federation graph httpapi notifications retry search sharing sync trash transfer versions \
+		activities app archiver auth eventstream federation graph httpapi notifications retry search sharing sync trash transfer versions \
 		webdav
 
 fmt:

README.md

@@ -170,7 +170,8 @@ The current profile is marked with `*` in `server list`.
 
 Run `ocis doctor [PROFILE]` to validate the config schema, operating-system
 credential service, authentication, advertised WebDAV capabilities, Spaces,
-public-link support, and resumable-upload support.
+public-link support, resumable uploads, archive downloads, and real-time event
+support.
 
 ## Spaces
 
@@ -653,6 +654,36 @@ directory. For example, `ocis download /demo ./ --recursive` creates
 `./demo/demo`. A destination that does not exist is created as the downloaded
 directory itself.
 
+## Archive downloads
+
+Ask the oCIS server to package one or more files and directories into a single
+ZIP or TAR download:
+
+```sh
+ocis archive formats
+ocis archive download /Documents /Photos/trip.jpg --output backup.zip
+ocis archive download /Documents --output backup.tar --format tar
+ocis archive download /Documents --output backup.zip --dry-run
+```
+
+The command is different from `download --recursive`: oCIS creates one archive
+on the server and the CLI downloads that one stream. `archive formats` shows
+the formats and source limits advertised by the selected server. The output
+format is inferred from `.tar`; otherwise it defaults to ZIP. A conflicting
+`.zip` or `.tar` extension is rejected.
+
+Before downloading, the CLI resolves every selected resource, walks selected
+directories, and checks the advertised entry-count and logical-size limits.
+Nested or duplicate selections are rejected so resources are not archived
+twice. `--dry-run` performs that complete preflight without requesting an
+archive or creating a local file. The server remains authoritative for access
+permissions, including within a selected Space.
+
+Archive downloads use the same authenticated profile as other commands. The
+CLI refuses a cross-origin archive endpoint advertised by a server, validates
+the complete ZIP or TAR stream, and atomically installs the result. Existing
+destinations are protected unless `--overwrite` is explicitly supplied.
+
 ## One-way synchronization
 
 Reconcile complete directory trees from one authoritative source:

internal/app/app_test.go

@@ -302,6 +302,10 @@ func TestDoctorValidatesProfileAndCapabilities(t *testing.T) {
 		case request.URL.Path == "/ocs/v2.php/cloud/capabilities":
 			writeAppOCS(writer, `{"capabilities":{
 				"core":{"support-sse":true},
+				"files":{"archivers":[{
+					"enabled":true,"version":"2.0.0","formats":["zip","tar"],
+					"archiver_url":"/archiver","max_num_files":"1000","max_size":"1000000"
+				}]},
 				"files_sharing":{"api_enabled":true,"public":{
 					"enabled":true,"password":{"enforced":false},
 					"expire_date":{"enabled":true}
@@ -338,6 +342,7 @@ func TestDoctorValidatesProfileAndCapabilities(t *testing.T) {
 	if !strings.Contains(rendered.String(), `"type": "diagnostic"`) ||
 		!strings.Contains(rendered.String(), `"DAV capabilities"`) ||
 		!strings.Contains(rendered.String(), `"public links"`) ||
+		!strings.Contains(rendered.String(), `"archive downloads"`) ||
 		!strings.Contains(rendered.String(), `"real-time events"`) {
 		t.Fatalf("output: %s", rendered.String())
 	}

internal/app/archive_api.go

@@ -0,0 +1,40 @@
+package app
+
+import "context"
+
+// ArchiveDownloadRequest describes one server-side archive download.
+type ArchiveDownloadRequest struct {
+	Paths       []string
+	Destination string
+	Format      string
+	Overwrite   bool
+	DryRun      bool
+}
+
+// RunArchiveDownloadWithOptions creates and downloads a server-side archive.
+func RunArchiveDownloadWithOptions(
+	ctx context.Context,
+	request ArchiveDownloadRequest,
+	selectedProfile string,
+	options RunOptions,
+) error {
+	return classifyProtocolError(
+		"archive download",
+		runArchiveDownload(
+			ctx, request, selectedProfile, options.normalized(),
+		),
+	)
+}
+
+// RunArchiveFormatsWithOptions lists formats advertised by the selected
+// server's preferred enabled archive service.
+func RunArchiveFormatsWithOptions(
+	ctx context.Context,
+	selectedProfile string,
+	options RunOptions,
+) error {
+	return classifyProtocolError(
+		"archive formats",
+		runArchiveFormats(ctx, selectedProfile, options.normalized()),
+	)
+}