feat(tools): add slide deck generation tool for the marp_slides ExApp

ex_app/lib/all_tools/slide_deck.py

@@ -0,0 +1,62 @@
+# SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Slide deck generation through the marp_slides ExApp."""
+from langchain_core.tools import tool
+from nc_py_api import AsyncNextcloudApp
+
+from ex_app.lib.all_tools.lib.impulse import ImpulseRadius, impulse
+from ex_app.lib.all_tools.lib.task_processing import run_task
+
+TASK_TYPE_ID = "marp_slides:slide_deck_generation"
+
+
+async def get_tools(nc: AsyncNextcloudApp):
+
+    @tool
+    @impulse(ImpulseRadius.SELF)
+    async def create_slide_deck(prompt: str, title: str = "Slide deck") -> str:
+        """Create a presentation as a PPTX slide deck from a deck brief.
+
+        The deck itself is written by the presentation tool's own AI, so pass a
+        brief and not slides, and no Marp or Markdown. Expand the user's request
+        into a self-contained brief: the topic and what it should cover, the
+        audience, the desired number of slides when the user indicated one, the
+        tone, and the language the user writes in, which is also the language
+        the deck and your reply should be in. Derive a short file title that
+        names the deck's subject instead of a generic one.
+        :param prompt: the deck brief: topic, audience, desired slide count if known, tone, language
+        :param title: a good file title for the generated deck, derived from the user's request
+        :return: a download link to the generated presentation
+        """
+        url = (
+            await nc.ocs(
+                "GET",
+                "/ocs/v2.php/apps/app_api/api/v1/info/nextcloud_url/absolute",
+                json={"url": "ocs/v2.php/apps/assistant/api/v1/task"},
+            )
+        )["absolute_url"]
+
+        # The task input shape has no title slot, so the title rides at the top
+        # of the brief: the provider's AI names the deck and its file from it.
+        task = await run_task(
+            nc,
+            TASK_TYPE_ID,
+            {
+                "prompt": f"Deck title: {title}\n\n{prompt}",
+                "output_format": "pptx",
+            },
+        )
+        return f"{url}/{task.id}/output-file/{task.output['slide_deck']}/download"
+
+    return [
+        create_slide_deck,
+    ]
+
+
+def get_category_name():
+    return "Slide deck generation"
+
+
+async def is_available(nc: AsyncNextcloudApp):
+    tasktypes = (await nc.ocs("GET", "/ocs/v2.php/taskprocessing/tasktypes"))["types"].keys()
+    return TASK_TYPE_ID in tasktypes

tests/test_slide_deck_tool.py

@@ -0,0 +1,109 @@
+# SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Hermetic tests for the slide_deck tool module.
+
+Everything runs against a fake AsyncNextcloudApp that records ocs() calls and
+serves canned task-processing responses: no network, no Nextcloud server, and
+no environment outside this worktree. The repo-wide ruff config selects S101
+(no assert statements) without a test file exemption, and the shared config
+must not be edited for this tool, so the checks below raise AssertionError
+from small helpers instead of using the assert keyword.
+"""
+import asyncio
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+from ex_app.lib.all_tools import slide_deck  # noqa: E402
+
+
+class FakeNextcloudApp:
+    """Records ocs() calls and answers the endpoints the module touches."""
+
+    def __init__(self, tasktypes=None, nextcloud_url="https://nc.example.test", task_id=42, file_id=1337):
+        self.tasktypes = dict(tasktypes or {})
+        self.nextcloud_url = nextcloud_url
+        self.task_id = task_id
+        self.file_id = file_id
+        self.ocs_calls = []
+
+    async def ocs(self, method, endpoint, json=None, **_kwargs):
+        self.ocs_calls.append((method, endpoint, json))
+        if endpoint == "/ocs/v2.php/taskprocessing/tasktypes":
+            return {"types": self.tasktypes}
+        if endpoint == "/ocs/v2.php/apps/app_api/api/v1/info/nextcloud_url/absolute":
+            # real endpoint returns a dict (app_api OCSApiController), not a bare string
+            return {"absolute_url": self.nextcloud_url}
+        if endpoint == "/ocs/v1.php/taskprocessing/schedule":
+            return {
+                "task": {
+                    "id": self.task_id,
+                    "status": "STATUS_SUCCESSFUL",
+                    "output": {"slide_deck": self.file_id},
+                }
+            }
+        raise AssertionError(f"unexpected ocs call: {method} {endpoint}")
+
+    async def log(self, level, content):
+        """Sink for run_task's debug logging."""
+
+    def schedule_calls(self):
+        return [call for call in self.ocs_calls if call[1] == "/ocs/v1.php/taskprocessing/schedule"]
+
+
+def expect_equal(actual, expected, label):
+    if actual != expected:
+        raise AssertionError(f"{label}: expected {expected!r}, got {actual!r}")
+
+
+async def call_slide_deck(nc, **tool_args):
+    tools = await slide_deck.get_tools(nc)
+    expect_equal([t.name for t in tools], ["create_slide_deck"], "tool names")
+    return await tools[0].ainvoke(tool_args)
+
+
+def test_schedules_brief_task_with_marp_task_type():
+    nc = FakeNextcloudApp()
+    brief = "A deck about tending bonsai for beginners, 8 slides, calm tone, German"
+    asyncio.run(call_slide_deck(nc, prompt=brief, title="Bonsai basics"))
+
+    expect_equal(len(nc.schedule_calls()), 1, "number of schedule calls")
+    (schedule,) = nc.schedule_calls()
+    method, endpoint, payload = schedule
+    expect_equal(method, "POST", "schedule method")
+    expect_equal(endpoint, "/ocs/v1.php/taskprocessing/schedule", "schedule endpoint")
+    expect_equal(payload["type"], "marp_slides:slide_deck_generation", "task type id")
+    expect_equal(payload["appId"], "context_agent", "scheduling app id")
+    expect_equal(
+        payload["input"],
+        {
+            "prompt": f"Deck title: Bonsai basics\n\n{brief}",
+            "output_format": "pptx",
+        },
+        "task input payload",
+    )
+
+
+def test_builds_download_link_from_slide_deck_output():
+    nc = FakeNextcloudApp(task_id=57, file_id=909)
+    link = asyncio.run(call_slide_deck(nc, prompt="Topic", title="T"))
+    expect_equal(link, "https://nc.example.test/57/output-file/909/download", "download link")
+
+
+def test_default_title_rides_in_the_brief():
+    nc = FakeNextcloudApp()
+    asyncio.run(call_slide_deck(nc, prompt="Topic"))
+    ((_, _, payload),) = nc.schedule_calls()
+    expect_equal(payload["input"]["prompt"].splitlines()[0], "Deck title: Slide deck", "default title line")
+    expect_equal(payload["input"]["output_format"], "pptx", "output format with default title")
+
+
+def test_is_available_true_when_task_type_registered():
+    nc = FakeNextcloudApp(tasktypes={"marp_slides:slide_deck_generation": {}, "core:text2text": {}})
+    expect_equal(asyncio.run(slide_deck.is_available(nc)), True, "availability with the ExApp registered")
+
+
+def test_is_available_false_without_task_type():
+    nc = FakeNextcloudApp(tasktypes={"core:text2text": {}})
+    expect_equal(asyncio.run(slide_deck.is_available(nc)), False, "availability without the ExApp")