diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index b96a5eb2d..7a4ff0d8a 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -57,7 +57,7 @@ jobs:
       - name: Test with pytest
         env:
           MP_API_KEY: ${{ secrets[env.API_KEY_NAME] }}
-          #MP_API_ENDPOINT: https://api-preview.materialsproject.org/
+          # MP_API_ENDPOINT: https://api-preview.materialsproject.org/
         run: |
           pip install -e .
           pytest -n auto -x --cov=mp_api --cov-report=xml
diff --git a/mp_api/client/core/client.py b/mp_api/client/core/client.py
index 793d0902f..81e80bd88 100644
--- a/mp_api/client/core/client.py
+++ b/mp_api/client/core/client.py
@@ -7,8 +7,10 @@
 
 import inspect
 import itertools
+import logging
 import os
 import platform
+import shutil
 import sys
 import warnings
 from concurrent.futures import FIRST_COMPLETED, ThreadPoolExecutor, wait
@@ -21,7 +23,10 @@
 from typing import TYPE_CHECKING, ForwardRef, Optional, get_args
 from urllib.parse import quote, urljoin
 
+import pyarrow as pa
+import pyarrow.dataset as ds
 import requests
+from deltalake import DeltaTable, QueryBuilder, convert_to_deltalake
 from emmet.core.utils import jsanitize
 from pydantic import BaseModel, create_model
 from requests.adapters import HTTPAdapter
@@ -31,7 +36,7 @@
 from urllib3.util.retry import Retry
 
 from mp_api.client.core.settings import MAPIClientSettings
-from mp_api.client.core.utils import load_json, validate_ids
+from mp_api.client.core.utils import MPDataset, load_json, validate_ids
 
 try:
     import boto3
@@ -58,6 +63,14 @@
 
 SETTINGS = MAPIClientSettings()  # type: ignore
 
+hdlr = logging.StreamHandler()
+fmt = logging.Formatter("%(name)s - %(levelname)s - %(message)s")
+hdlr.setFormatter(fmt)
+
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.INFO)
+logger.addHandler(hdlr)
+
 
 class _DictLikeAccess(BaseModel):
     """Define a pydantic mix-in which permits dict-like access to model fields."""
@@ -83,6 +96,7 @@ class BaseRester:
     document_model: type[BaseModel] | None = None
     supports_versions: bool = False
     primary_key: str = "material_id"
+    delta_backed: bool = False
 
     def __init__(
         self,
@@ -97,6 +111,8 @@ def __init__(
         timeout: int = 20,
         headers: dict | None = None,
         mute_progress_bars: bool = SETTINGS.MUTE_PROGRESS_BARS,
+        local_dataset_cache: str | os.PathLike = SETTINGS.LOCAL_DATASET_CACHE,
+        force_renew: bool = False,
     ):
         """Initialize the REST API helper class.
 
@@ -128,6 +144,9 @@ def __init__(
             timeout: Time in seconds to wait until a request timeout error is thrown
             headers: Custom headers for localhost connections.
             mute_progress_bars: Whether to disable progress bars.
+            local_dataset_cache: Target directory for downloading full datasets. Defaults
+                to 'mp_datasets' in the user's home directory
+            force_renew: Option to overwrite existing local dataset
         """
         # TODO: think about how to migrate from PMG_MAPI_KEY
         self.api_key = api_key or os.getenv("MP_API_KEY")
@@ -141,7 +160,12 @@ def __init__(
         self.timeout = timeout
         self.headers = headers or {}
         self.mute_progress_bars = mute_progress_bars
-        self.db_version = BaseRester._get_database_version(self.endpoint)
+        self.local_dataset_cache = local_dataset_cache
+        self.force_renew = force_renew
+        (
+            self.db_version,
+            self.access_controlled_batch_ids,
+        ) = BaseRester._get_heartbeat_info(self.endpoint)
 
         if self.suffix:
             self.endpoint = urljoin(self.endpoint, self.suffix)
@@ -216,8 +240,9 @@ def __exit__(self, exc_type, exc_val, exc_tb):  # pragma: no cover
 
     @staticmethod
     @cache
-    def _get_database_version(endpoint):
-        """The Materials Project database is periodically updated and has a
+    def _get_heartbeat_info(endpoint) -> tuple[str, str]:
+        """DB version:
+        The Materials Project database is periodically updated and has a
         database version associated with it. When the database is updated,
         consolidated data (information about "a material") may and does
         change, while calculation data about a specific calculation task
@@ -227,9 +252,24 @@ def _get_database_version(endpoint):
         where "_DD" may be optional. An additional numerical or `postN` suffix
         might be added if multiple releases happen on the same day.
 
-        Returns: database version as a string
+        Access Controlled Datasets:
+        Certain contributions to the Materials Project have access
+        control restrictions that require explicit agreement to the
+        Terms of Use for the respective datasets prior to access being
+        granted.
+
+        A full list of the Terms of Use for all contributions in the
+        Materials Project are available at:
+
+        https://next-gen.materialsproject.org/about/terms
+
+        Returns:
+            tuple with database version as a string and a comma separated
+            string with all calculation batch identifiers that have access
+            restrictions
         """
-        return requests.get(url=endpoint + "heartbeat").json()["db_version"]
+        response = requests.get(url=endpoint + "heartbeat").json()
+        return response["db_version"], response["access_controlled_batch_ids"]
 
     def _post_resource(
         self,
@@ -368,10 +408,7 @@ def _patch_resource(
             raise MPRestError(str(ex))
 
     def _query_open_data(
-        self,
-        bucket: str,
-        key: str,
-        decoder: Callable | None = None,
+        self, bucket: str, key: str, decoder: Callable | None = None
     ) -> tuple[list[dict] | list[bytes], int]:
         """Query and deserialize Materials Project AWS open data s3 buckets.
 
@@ -471,6 +508,12 @@ def _query_resource(
                     url += "/"
 
             if query_s3:
+                pbar_message = (  # type: ignore
+                    f"Retrieving {self.document_model.__name__} documents"  # type: ignore
+                    if self.document_model is not None
+                    else "Retrieving documents"
+                )
+
                 db_version = self.db_version.replace(".", "-")
                 if "/" not in self.suffix:
                     suffix = self.suffix
@@ -481,15 +524,169 @@ def _query_resource(
                     suffix = infix if suffix == "core" else suffix
                     suffix = suffix.replace("_", "-")
 
-                # Paginate over all entries in the bucket.
-                # TODO: change when a subset of entries needed from DB
+                # Check if user has access to GNoMe
+                # temp suppress tqdm
+                re_enable = not self.mute_progress_bars
+                self.mute_progress_bars = True
+                has_gnome_access = bool(
+                    self._submit_requests(
+                        url=urljoin(self.base_endpoint, "materials/summary/"),
+                        criteria={
+                            "batch_id": "gnome_r2scan_statics",
+                            "_fields": "material_id",
+                        },
+                        use_document_model=False,
+                        num_chunks=1,
+                        chunk_size=1,
+                        timeout=timeout,
+                    )
+                    .get("meta", {})
+                    .get("total_doc", 0)
+                )
+                self.mute_progress_bars = not re_enable
+
                 if "tasks" in suffix:
-                    bucket_suffix, prefix = "parsed", "tasks_atomate2"
+                    bucket_suffix, prefix = ("parsed", "core/tasks/")
                 else:
                     bucket_suffix = "build"
                     prefix = f"collections/{db_version}/{suffix}"
 
                 bucket = f"materialsproject-{bucket_suffix}"
+
+                if self.delta_backed:
+                    target_path = str(
+                        self.local_dataset_cache.joinpath(f"{bucket_suffix}/{prefix}")
+                    )
+                    os.makedirs(target_path, exist_ok=True)
+
+                    if DeltaTable.is_deltatable(target_path):
+                        if self.force_renew:
+                            shutil.rmtree(target_path)
+                            logger.warning(
+                                f"Regenerating {suffix} dataset at {target_path}..."
+                            )
+                            os.makedirs(target_path, exist_ok=True)
+                        else:
+                            logger.warning(
+                                f"Dataset for {suffix} already exists at {target_path}, returning existing dataset."
+                            )
+                            logger.info(
+                                "Delete or move existing dataset or re-run search query with MPRester(force_renew=True) "
+                                "to refresh local dataset.",
+                            )
+
+                            return {
+                                "data": MPDataset(
+                                    path=target_path,
+                                    document_model=self.document_model,
+                                    use_document_model=self.use_document_model,
+                                )
+                            }
+
+                    tbl = DeltaTable(
+                        f"s3a://{bucket}/{prefix}",
+                        storage_options={
+                            "AWS_SKIP_SIGNATURE": "true",
+                            "AWS_REGION": "us-east-1",
+                        },
+                    )
+
+                    controlled_batch_str = ",".join(
+                        [f"'{tag}'" for tag in self.access_controlled_batch_ids]
+                    )
+
+                    predicate = (
+                        " WHERE batch_id NOT IN ("  # don't delete leading space
+                        + controlled_batch_str
+                        + ")"
+                        if not has_gnome_access
+                        else ""
+                    )
+
+                    builder = QueryBuilder().register("tbl", tbl)
+
+                    # Setup progress bar
+                    num_docs_needed = pa.table(
+                        builder.execute("SELECT COUNT(*) FROM tbl").read_all()
+                    )[0][0].as_py()
+
+                    if not has_gnome_access:
+                        num_docs_needed = self.count(
+                            {"batch_id_neq_any": self.access_controlled_batch_ids}
+                        )
+
+                    pbar = (
+                        tqdm(
+                            desc=pbar_message,
+                            total=num_docs_needed,
+                        )
+                        if not self.mute_progress_bars
+                        else None
+                    )
+
+                    iterator = builder.execute("SELECT * FROM tbl" + predicate)
+
+                    file_options = ds.ParquetFileFormat().make_write_options(
+                        compression="zstd"
+                    )
+
+                    def _flush(accumulator, group):
+                        ds.write_dataset(
+                            accumulator,
+                            base_dir=target_path,
+                            format="parquet",
+                            basename_template=f"group-{group}-"
+                            + "part-{i}.zstd.parquet",
+                            existing_data_behavior="overwrite_or_ignore",
+                            max_rows_per_group=1024,
+                            file_options=file_options,
+                        )
+
+                    group = 1
+                    size = 0
+                    accumulator = []
+                    for page in iterator:
+                        # arro3 rb to pyarrow rb for compat w/ pyarrow ds writer
+                        rg = pa.record_batch(page)
+                        accumulator.append(rg)
+                        page_size = page.num_rows
+                        size += rg.get_total_buffer_size()
+
+                        if pbar is not None:
+                            pbar.update(page_size)
+
+                        if size >= SETTINGS.DATASET_FLUSH_THRESHOLD:
+                            _flush(accumulator, group)
+                            group += 1
+                            size = 0
+                            accumulator.clear()
+
+                    if accumulator:
+                        _flush(accumulator, group + 1)
+
+                    if pbar is not None:
+                        pbar.close()
+
+                    logger.info(f"Dataset for {suffix} written to {target_path}")
+                    logger.info("Converting to DeltaTable...")
+
+                    convert_to_deltalake(target_path)
+
+                    logger.info(
+                        "Consult the delta-rs and pyarrow documentation for advanced usage: "
+                        "delta-io.github.io/delta-rs/, arrow.apache.org/docs/python/"
+                    )
+
+                    return {
+                        "data": MPDataset(
+                            path=target_path,
+                            document_model=self.document_model,
+                            use_document_model=self.use_document_model,
+                        )
+                    }
+
+                # Paginate over all entries in the bucket.
+                # TODO: change when a subset of entries needed from DB
                 paginator = self.s3_client.get_paginator("list_objects_v2")
                 pages = paginator.paginate(Bucket=bucket, Prefix=prefix)
 
@@ -526,11 +723,6 @@ def _query_resource(
                 }
 
                 # Setup progress bar
-                pbar_message = (  # type: ignore
-                    f"Retrieving {self.document_model.__name__} documents"  # type: ignore
-                    if self.document_model is not None
-                    else "Retrieving documents"
-                )
                 num_docs_needed = int(self.count())
                 pbar = (
                     tqdm(
diff --git a/mp_api/client/core/settings.py b/mp_api/client/core/settings.py
index 200b67785..09926fe82 100644
--- a/mp_api/client/core/settings.py
+++ b/mp_api/client/core/settings.py
@@ -1,5 +1,6 @@
 import os
 from multiprocessing import cpu_count
+from pathlib import Path
 from typing import List
 
 from pydantic import Field
@@ -50,6 +51,7 @@ class MAPIClientSettings(BaseSettings):
             "condition_mixing_media",
             "condition_heating_atmosphere",
             "operations",
+            "batch_id_neq_any",
             "_fields",
         ],
         description="List API query parameters that do not support parallel requests.",
@@ -87,4 +89,14 @@ class MAPIClientSettings(BaseSettings):
         _MAX_LIST_LENGTH, description="Maximum length of query parameter list"
     )
 
+    LOCAL_DATASET_CACHE: Path = Field(
+        Path("~/mp_datasets").expanduser(),
+        description="Target directory for downloading full datasets",
+    )
+
+    DATASET_FLUSH_THRESHOLD: int = Field(
+        int(2.75 * 1024**3),
+        description="Threshold bytes to accumulate in memory before flushing dataset to disk",
+    )
+
     model_config = SettingsConfigDict(env_prefix="MPRESTER_")
diff --git a/mp_api/client/core/utils.py b/mp_api/client/core/utils.py
index c2d03fec2..b549d5b2f 100644
--- a/mp_api/client/core/utils.py
+++ b/mp_api/client/core/utils.py
@@ -1,12 +1,17 @@
 from __future__ import annotations
 
 import re
+from functools import cached_property
+from itertools import chain
 from typing import TYPE_CHECKING, Literal
 
 import orjson
+import pyarrow.dataset as ds
+from deltalake import DeltaTable
 from emmet.core import __version__ as _EMMET_CORE_VER
 from monty.json import MontyDecoder
 from packaging.version import parse as parse_version
+from pydantic._internal._model_construction import ModelMetaclass
 
 from mp_api.client.core.settings import MAPIClientSettings
 
@@ -124,3 +129,68 @@ def validate_monty(cls, v, _):
     monty_cls.validate_monty_v2 = classmethod(validate_monty)
 
     return monty_cls
+
+
+class MPDataset:
+    def __init__(self, path, document_model, use_document_model):
+        """Convenience wrapper for pyarrow datasets stored on disk."""
+        self._start = 0
+        self._path = path
+        self._document_model = document_model
+        self._dataset = ds.dataset(path)
+        self._row_groups = list(
+            chain.from_iterable(
+                [
+                    fragment.split_by_row_group()
+                    for fragment in self._dataset.get_fragments()
+                ]
+            )
+        )
+        self._use_document_model = use_document_model
+
+    @property
+    def pyarrow_dataset(self) -> ds.Dataset:
+        return self._dataset
+
+    @property
+    def pydantic_model(self) -> ModelMetaclass:
+        return self._document_model
+
+    @property
+    def use_document_model(self) -> bool:
+        return self._use_document_model
+
+    @use_document_model.setter
+    def use_document_model(self, value: bool):
+        self._use_document_model = value
+
+    @cached_property
+    def delta_table(self) -> DeltaTable:
+        return DeltaTable(self._path)
+
+    @cached_property
+    def num_chunks(self) -> int:
+        return len(self._row_groups)
+
+    def __getitem__(self, idx):
+        if isinstance(idx, slice):
+            start, stop, step = idx.indices(len(self))
+            _take = list(range(start, stop, step))
+            ds_slice = self._dataset.take(_take).to_pylist(maps_as_pydicts="strict")
+            return (
+                [self._document_model(**_row) for _row in ds_slice]
+                if self._use_document_model
+                else ds_slice
+            )
+
+        _row = self._dataset.take([idx]).to_pylist(maps_as_pydicts="strict")[0]
+        return self._document_model(**_row) if self._use_document_model else _row
+
+    def __len__(self) -> int:
+        return self._dataset.count_rows()
+
+    def __iter__(self):
+        current = self._start
+        while current < len(self):
+            yield self[current]
+            current += 1
diff --git a/mp_api/client/mprester.py b/mp_api/client/mprester.py
index e6f65c964..8f2752cb1 100644
--- a/mp_api/client/mprester.py
+++ b/mp_api/client/mprester.py
@@ -134,6 +134,8 @@ def __init__(
         session: Session | None = None,
         headers: dict | None = None,
         mute_progress_bars: bool = _MAPI_SETTINGS.MUTE_PROGRESS_BARS,
+        local_dataset_cache: str | os.PathLike = _MAPI_SETTINGS.LOCAL_DATASET_CACHE,
+        force_renew: bool = False,
     ):
         """Initialize the MPRester.
 
@@ -168,6 +170,9 @@ def __init__(
             session: Session object to use. By default (None), the client will create one.
             headers: Custom headers for localhost connections.
             mute_progress_bars:  Whether to mute progress bars.
+            local_dataset_cache: Target directory for downloading full datasets. Defaults
+                to "mp_datasets" in the user's home directory
+            force_renew: Option to overwrite existing local dataset
 
         """
         # SETTINGS tries to read API key from ~/.config/.pmgrc.yaml
@@ -193,6 +198,8 @@ def __init__(
         self.use_document_model = use_document_model
         self.monty_decode = monty_decode
         self.mute_progress_bars = mute_progress_bars
+        self.local_dataset_cache = local_dataset_cache
+        self.force_renew = force_renew
         self._contribs = None
 
         self._deprecated_attributes = [
@@ -268,6 +275,8 @@ def __init__(
                 use_document_model=self.use_document_model,
                 headers=self.headers,
                 mute_progress_bars=self.mute_progress_bars,
+                local_dataset_cache=self.local_dataset_cache,
+                force_renew=self.force_renew,
             )
             for cls in self._all_resters
             if cls.suffix in core_suffix
@@ -294,6 +303,8 @@ def __init__(
                         use_document_model=self.use_document_model,
                         headers=self.headers,
                         mute_progress_bars=self.mute_progress_bars,
+                        local_dataset_cache=self.local_dataset_cache,
+                        force_renew=self.force_renew,
                     )  # type: BaseRester
                     setattr(
                         self,
@@ -324,6 +335,8 @@ def __core_custom_getattr(_self, _attr, _rester_map):
                     use_document_model=self.use_document_model,
                     headers=self.headers,
                     mute_progress_bars=self.mute_progress_bars,
+                    local_dataset_cache=self.local_dataset_cache,
+                    force_renew=self.force_renew,
                 )  # type: BaseRester
 
                 setattr(
diff --git a/mp_api/client/routes/materials/tasks.py b/mp_api/client/routes/materials/tasks.py
index c78650780..a879a93c4 100644
--- a/mp_api/client/routes/materials/tasks.py
+++ b/mp_api/client/routes/materials/tasks.py
@@ -3,7 +3,11 @@
 from datetime import datetime
 from typing import TYPE_CHECKING
 
+import pyarrow as pa
+from deltalake import DeltaTable, QueryBuilder
+from emmet.core.mpid import AlphaID
 from emmet.core.tasks import CoreTaskDoc
+from emmet.core.trajectory import RelaxTrajectory
 
 from mp_api.client.core import BaseRester, MPRestError
 from mp_api.client.core.utils import validate_ids
@@ -16,6 +20,7 @@ class TaskRester(BaseRester):
     suffix: str = "materials/tasks"
     document_model: type[BaseModel] = CoreTaskDoc  # type: ignore
     primary_key: str = "task_id"
+    delta_backed = True
 
     def get_trajectory(self, task_id):
         """Returns a Trajectory object containing the geometry of the
@@ -26,16 +31,30 @@ def get_trajectory(self, task_id):
             task_id (str): Task ID
 
         """
-        traj_data = self._query_resource_data(
-            {"task_ids": [task_id]}, suburl="trajectory/", use_document_model=False
-        )[0].get(
-            "trajectories", None
-        )  # type: ignore
+        as_alpha = str(AlphaID(task_id, padlen=8)).split("-")[-1]
 
-        if traj_data is None:
+        traj_tbl = DeltaTable(
+            "s3a://materialsproject-parsed/core/trajectories/",
+            storage_options={"AWS_SKIP_SIGNATURE": "true", "AWS_REGION": "us-east-1"},
+        )
+
+        traj_data = pa.table(
+            QueryBuilder()
+            .register("traj", traj_tbl)
+            .execute(
+                f"""
+                SELECT *
+                FROM   traj
+                WHERE  identifier='{as_alpha}'
+                """
+            )
+            .read_all()
+        ).to_pylist(maps_as_pydicts="strict")
+
+        if not traj_data:
             raise MPRestError(f"No trajectory data for {task_id} found")
 
-        return traj_data
+        return RelaxTrajectory(**traj_data[0]).to_pmg().as_dict()
 
     def search(
         self,
diff --git a/pyproject.toml b/pyproject.toml
index afefc1e06..9370f21ae 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,6 +29,8 @@ dependencies = [
   "smart_open",
   "boto3",
   "orjson >= 3.10,<4",
+  "pyarrow >= 20.0.0",
+  "deltalake >= 1.2.0",
 ]
 dynamic = ["version"]
 
diff --git a/requirements/requirements-ubuntu-latest_py3.11.txt b/requirements/requirements-ubuntu-latest_py3.11.txt
index d3ff66cb4..f817130ab 100644
--- a/requirements/requirements-ubuntu-latest_py3.11.txt
+++ b/requirements/requirements-ubuntu-latest_py3.11.txt
@@ -6,6 +6,8 @@
 #
 annotated-types==0.7.0
     # via pydantic
+arro3-core==0.6.5
+    # via deltalake
 bibtexparser==1.4.3
     # via pymatgen
 blake3==1.0.8
@@ -24,7 +26,11 @@ contourpy==1.3.3
     # via matplotlib
 cycler==0.12.1
     # via matplotlib
-emmet-core==0.86.0
+deltalake==1.2.1
+    # via mp-api (pyproject.toml)
+deprecated==1.3.1
+    # via deltalake
+emmet-core==0.86.0rc1
     # via mp-api (pyproject.toml)
 fonttools==4.60.1
     # via matplotlib
@@ -81,6 +87,8 @@ pillow==12.0.0
     # via matplotlib
 plotly==6.4.0
     # via pymatgen
+pyarrow==22.0.0
+    # via mp-api (pyproject.toml)
 pybtex==0.25.1
     # via emmet-core
 pydantic==2.12.4
@@ -145,6 +153,7 @@ tqdm==4.67.1
     # via pymatgen
 typing-extensions==4.15.0
     # via
+    #   arro3-core
     #   blake3
     #   emmet-core
     #   mp-api (pyproject.toml)
@@ -165,4 +174,6 @@ urllib3==2.5.0
     #   botocore
     #   requests
 wrapt==2.0.0
-    # via smart-open
+    # via
+    #   deprecated
+    #   smart-open
diff --git a/requirements/requirements-ubuntu-latest_py3.11_extras.txt b/requirements/requirements-ubuntu-latest_py3.11_extras.txt
index 59ac2f166..0a7c52cdb 100644
--- a/requirements/requirements-ubuntu-latest_py3.11_extras.txt
+++ b/requirements/requirements-ubuntu-latest_py3.11_extras.txt
@@ -8,6 +8,8 @@ alabaster==1.0.0
     # via sphinx
 annotated-types==0.7.0
     # via pydantic
+arro3-core==0.6.5
+    # via deltalake
 arrow==1.4.0
     # via isoduration
 ase==3.26.0
@@ -54,6 +56,10 @@ cycler==0.12.1
     # via matplotlib
 decorator==5.2.1
     # via ipython
+deltalake==1.2.1
+    # via mp-api (pyproject.toml)
+deprecated==1.3.1
+    # via deltalake
 distlib==0.4.0
     # via virtualenv
 dnspython==2.8.0
@@ -271,7 +277,9 @@ pubchempy==1.0.5
 pure-eval==0.2.3
     # via stack-data
 pyarrow==22.0.0
-    # via emmet-core
+    # via
+    #   emmet-core
+    #   mp-api (pyproject.toml)
 pybtex==0.25.1
     # via
     #   emmet-core
@@ -491,6 +499,7 @@ types-setuptools==80.9.0.20250822
     # via mp-api (pyproject.toml)
 typing-extensions==4.15.0
     # via
+    #   arro3-core
     #   blake3
     #   bravado
     #   emmet-core
@@ -534,4 +543,6 @@ wcwidth==0.2.14
 webcolors==25.10.0
     # via jsonschema
 wrapt==2.0.0
-    # via smart-open
+    # via
+    #   deprecated
+    #   smart-open
diff --git a/requirements/requirements-ubuntu-latest_py3.12.txt b/requirements/requirements-ubuntu-latest_py3.12.txt
index 29ee10749..831da0d10 100644
--- a/requirements/requirements-ubuntu-latest_py3.12.txt
+++ b/requirements/requirements-ubuntu-latest_py3.12.txt
@@ -6,6 +6,8 @@
 #
 annotated-types==0.7.0
     # via pydantic
+arro3-core==0.6.5
+    # via deltalake
 bibtexparser==1.4.3
     # via pymatgen
 blake3==1.0.8
@@ -24,7 +26,11 @@ contourpy==1.3.3
     # via matplotlib
 cycler==0.12.1
     # via matplotlib
-emmet-core==0.86.0
+deltalake==1.2.1
+    # via mp-api (pyproject.toml)
+deprecated==1.3.1
+    # via deltalake
+emmet-core==0.86.0rc1
     # via mp-api (pyproject.toml)
 fonttools==4.60.1
     # via matplotlib
@@ -81,6 +87,8 @@ pillow==12.0.0
     # via matplotlib
 plotly==6.4.0
     # via pymatgen
+pyarrow==22.0.0
+    # via mp-api (pyproject.toml)
 pybtex==0.25.1
     # via emmet-core
 pydantic==2.12.4
@@ -164,4 +172,6 @@ urllib3==2.5.0
     #   botocore
     #   requests
 wrapt==2.0.0
-    # via smart-open
+    # via
+    #   deprecated
+    #   smart-open
diff --git a/requirements/requirements-ubuntu-latest_py3.12_extras.txt b/requirements/requirements-ubuntu-latest_py3.12_extras.txt
index 9b4c609a5..ebf193dce 100644
--- a/requirements/requirements-ubuntu-latest_py3.12_extras.txt
+++ b/requirements/requirements-ubuntu-latest_py3.12_extras.txt
@@ -8,6 +8,8 @@ alabaster==1.0.0
     # via sphinx
 annotated-types==0.7.0
     # via pydantic
+arro3-core==0.6.5
+    # via deltalake
 arrow==1.4.0
     # via isoduration
 ase==3.26.0
@@ -54,6 +56,10 @@ cycler==0.12.1
     # via matplotlib
 decorator==5.2.1
     # via ipython
+deltalake==1.2.1
+    # via mp-api (pyproject.toml)
+deprecated==1.3.1
+    # via deltalake
 distlib==0.4.0
     # via virtualenv
 dnspython==2.8.0
@@ -271,7 +277,9 @@ pubchempy==1.0.5
 pure-eval==0.2.3
     # via stack-data
 pyarrow==22.0.0
-    # via emmet-core
+    # via
+    #   emmet-core
+    #   mp-api (pyproject.toml)
 pybtex==0.25.1
     # via
     #   emmet-core
@@ -532,4 +540,6 @@ wcwidth==0.2.14
 webcolors==25.10.0
     # via jsonschema
 wrapt==2.0.0
-    # via smart-open
+    # via
+    #   deprecated
+    #   smart-open
diff --git a/tests/materials/test_tasks.py b/tests/materials/test_tasks.py
index b35dfd938..1ddf12c58 100644
--- a/tests/materials/test_tasks.py
+++ b/tests/materials/test_tasks.py
@@ -1,8 +1,9 @@
 import os
-from core_function import client_search_testing
-import pytest
 
+import pytest
+from core_function import client_search_testing
 from emmet.core.utils import utcnow
+
 from mp_api.client.routes.materials.tasks import TaskRester
 
 
@@ -53,7 +54,6 @@ def test_client(rester):
 
 
 def test_get_trajectories(rester):
-    trajectories = [traj for traj in rester.get_trajectory("mp-149")]
+    trajectory = rester.get_trajectory("mp-149")
 
-    for traj in trajectories:
-        assert ("@module", "pymatgen.core.trajectory") in traj.items()
+    assert trajectory["@module"] == "pymatgen.core.trajectory"