diff --git a/charmcraft/application/commands/__init__.py b/charmcraft/application/commands/__init__.py
index 52c624fce..ed8e8f666 100644
--- a/charmcraft/application/commands/__init__.py
+++ b/charmcraft/application/commands/__init__.py
@@ -30,6 +30,7 @@
 from charmcraft.application.commands.remote import RemoteBuild
 from charmcraft.application.commands.store import (
     # auth
+    FetchLibs,
     LoginCommand,
     LogoutCommand,
     WhoamiCommand,
@@ -102,6 +103,7 @@ def fill_command_groups(app: craft_application.Application) -> None:
             CreateLibCommand,
             PublishLibCommand,
             ListLibCommand,
+            FetchLibs,
             FetchLibCommand,
         ],
     )
diff --git a/charmcraft/application/commands/store.py b/charmcraft/application/commands/store.py
index cfd241ecd..7669b5e28 100644
--- a/charmcraft/application/commands/store.py
+++ b/charmcraft/application/commands/store.py
@@ -28,9 +28,10 @@
 import zipfile
 from collections.abc import Collection
 from operator import attrgetter
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 import yaml
+from craft_application import util
 from craft_cli import ArgumentParsingError, emit
 from craft_cli.errors import CraftError
 from craft_parts import Step
@@ -41,7 +42,7 @@
 from tabulate import tabulate
 
 import charmcraft.store.models
-from charmcraft import const, env, parts, utils
+from charmcraft import const, env, errors, parts, utils
 from charmcraft.application.commands.base import CharmcraftCommand
 from charmcraft.models import project
 from charmcraft.store import ImageHandler, LocalDockerdInterface, OCIRegistry, Store
@@ -1510,6 +1511,7 @@ class FetchLibCommand(CharmcraftCommand):
     )
     format_option = True
     always_load_project = True
+    hidden = True
 
     def fill_parser(self, parser):
         """Add own parameters to the general parser."""
@@ -1520,7 +1522,7 @@ def fill_parser(self, parser):
             help="Library to fetch (e.g. charms.mycharm.v2.foo.); optional, default to all",
         )
 
-    def run(self, parsed_args):
+    def run(self, parsed_args: argparse.Namespace) -> None:
         """Run the command."""
         if parsed_args.library:
             local_libs_data = [utils.get_lib_info(full_name=parsed_args.library)]
@@ -1534,10 +1536,9 @@ def run(self, parsed_args):
         to_query = []
         for lib in local_libs_data:
             if lib.lib_id is None:
-                item = {"charm_name": lib.charm_name, "lib_name": lib.lib_name}
+                item = {"charm_name": lib.charm_name, "lib_name": lib.lib_name, "api": lib.api}
             else:
-                item = {"lib_id": lib.lib_id}
-            item["api"] = lib.api
+                item = {"lib_id": lib.lib_id, "api": lib.api}
             to_query.append(item)
         libs_tips = store.get_libraries_tips(to_query)
 
@@ -1617,7 +1618,7 @@ def run(self, parsed_args):
         if parsed_args.format:
             output_data = []
             for lib_data, error_message in full_lib_data:
-                datum = {
+                datum: dict[str, Any] = {
                     "charm_name": lib_data.charm_name,
                     "library_name": lib_data.lib_name,
                     "library_id": lib_data.lib_id,
@@ -1634,6 +1635,94 @@ def run(self, parsed_args):
             emit.message(cli.format_content(output_data, parsed_args.format))
 
 
+class FetchLibs(CharmcraftCommand):
+    """Fetch libraries defined in charmcraft.yaml."""
+
+    name = "fetch-libs"
+    help_msg = "Fetch one or more charm libraries"
+    overview = textwrap.dedent(
+        """
+        Fetch charm libraries defined in charmcraft.yaml.
+
+        For each library in the top-level `charm-libs` key, fetch the latest library
+        version matching those requirements.
+
+        For example:
+        charm-libs:
+          # Fetch lib with API version 0.
+          # If `fetch-libs` is run and a newer minor version is available,
+          # it will be fetched from the store.
+          - lib: postgresql.postgres_client
+            version: "0"
+          # Always fetch precisely version 0.57.
+          - lib: mysql.client
+            version: "0.57"
+        """
+    )
+    format_option = True
+    always_load_project = True
+
+    def run(self, parsed_args: argparse.Namespace) -> None:
+        """Fetch libraries."""
+        store = self._services.store
+        charm_libs = self._services.project.charm_libs
+        if not charm_libs:
+            raise errors.LibraryError(
+                message="No dependent libraries declared in charmcraft.yaml.",
+                resolution="Add a 'charm-libs' section to charmcraft.yaml.",
+                retcode=78,  # EX_CONFIG: configuration error
+            )
+        emit.progress("Getting library metadata from charmhub")
+        libs_metadata = store.get_libraries_metadata_by_name(charm_libs)
+        declared_libs = {lib.lib: lib for lib in charm_libs}
+        missing_store_libs = declared_libs.keys() - libs_metadata.keys()
+        if missing_store_libs:
+            missing_libs_source = [declared_libs[lib].dict() for lib in sorted(missing_store_libs)]
+            libs_yaml = util.dump_yaml(missing_libs_source)
+            raise errors.CraftError(
+                f"Could not find the following libraries on charmhub:\n{libs_yaml}",
+                resolution="Use 'charmcraft list-lib' to check library names and versions.",
+                reportable=False,
+                logpath_report=False,
+            )
+
+        emit.trace(f"Library metadata retrieved: {libs_metadata}")
+        local_libs = {
+            f"{lib.charm_name}.{lib.lib_name}": lib for lib in utils.get_libs_from_tree()
+        }
+        emit.trace(f"Local libraries: {local_libs}")
+
+        downloaded_libs = 0
+        for lib_md in libs_metadata.values():
+            lib_name = f"{lib_md.charm_name}.{lib_md.lib_name}"
+            local_lib = local_libs.get(lib_name)
+            if local_lib and local_lib.content_hash == lib_md.content_hash:
+                emit.debug(
+                    f"Skipping {lib_name} because the same file already exists on "
+                    f"disk (hash: {lib_md.content_hash}). "
+                    "Delete the file and re-run 'charmcraft fetch-libs' to force re-download."
+                )
+                continue
+            lib_name = utils.get_lib_module_name(lib_md.charm_name, lib_md.lib_name, lib_md.api)
+            emit.progress(f"Downloading {lib_name}")
+            lib = store.get_library(
+                charm_name=lib_md.charm_name,
+                library_id=lib_md.lib_id,
+                api=lib_md.api,
+                patch=lib_md.patch,
+            )
+            if lib.content is None:
+                raise errors.CraftError(
+                    f"Store returned no content for '{lib.charm_name}.{lib.lib_name}'"
+                )
+            downloaded_libs += 1
+            lib_path = utils.get_lib_path(lib_md.charm_name, lib_md.lib_name, lib_md.api)
+            lib_path.parent.mkdir(exist_ok=True, parents=True)
+            lib_path.write_text(lib.content)
+
+        emit.message(f"Downloaded {downloaded_libs} charm libraries.")
+
+
 class ListLibCommand(CharmcraftCommand):
     """List all libraries belonging to a charm."""
 
diff --git a/charmcraft/errors.py b/charmcraft/errors.py
index ac7cd8439..a12af5c04 100644
--- a/charmcraft/errors.py
+++ b/charmcraft/errors.py
@@ -50,7 +50,11 @@ def __init__(
         )
 
 
-class BadLibraryPathError(CraftError):
+class LibraryError(CraftError):
+    """Errors related to charm libraries."""
+
+
+class BadLibraryPathError(LibraryError):
     """Subclass to provide a specific error for a bad library path."""
 
     def __init__(self, path):
@@ -59,7 +63,7 @@ def __init__(self, path):
         )
 
 
-class BadLibraryNameError(CraftError):
+class BadLibraryNameError(LibraryError):
     """Subclass to provide a specific error for a bad library name."""
 
     def __init__(self, name):
diff --git a/charmcraft/models/__init__.py b/charmcraft/models/__init__.py
index 05515b33f..0131f9348 100644
--- a/charmcraft/models/__init__.py
+++ b/charmcraft/models/__init__.py
@@ -24,6 +24,7 @@
 from .project import (
     CharmBuildInfo,
     CharmcraftBuildPlanner,
+    CharmLib,
     CharmcraftProject,
     BasesCharm,
     PlatformCharm,
@@ -48,6 +49,7 @@
     "CharmBuildInfo",
     "CharmcraftBuildPlanner",
     "CharmcraftProject",
+    "CharmLib",
     "BundleMetadata",
     "CharmMetadata",
     "CharmMetadataLegacy",
diff --git a/charmcraft/models/project.py b/charmcraft/models/project.py
index 51ae653f8..cc32425e8 100644
--- a/charmcraft/models/project.py
+++ b/charmcraft/models/project.py
@@ -17,6 +17,7 @@
 import abc
 import datetime
 import pathlib
+import re
 from collections.abc import Iterable, Iterator
 from typing import (
     Any,
@@ -120,6 +121,76 @@ def _listify_architectures(cls, value: str | list[str]) -> list[str]:
         return value
 
 
+class CharmLib(models.CraftBaseModel):
+    """A Charm library dependency for this charm."""
+
+    lib: str = pydantic.Field(
+        title="Library Path (e.g. my_charm.my_library)",
+        regex=r"[a-z0-9_]+\.[a-z0-9_]+",
+    )
+    version: str = pydantic.Field(
+        title="Version filter for the charm. Either an API version or a specific [api].[patch].",
+        regex=r"[0-9]+(\.[0-9]+)?",
+    )
+
+    @pydantic.validator("lib", pre=True)
+    def _validate_name(cls, value: str) -> str:
+        """Validate the lib field, providing a useful error message on failure."""
+        charm_name, _, lib_name = str(value).partition(".")
+        if not charm_name or not lib_name:
+            raise ValueError(
+                f"Library name invalid. Expected '[charm_name].[lib_name]', got {value!r}"
+            )
+        if not re.fullmatch("[a-z0-9_]+", charm_name):
+            if "-" in charm_name:
+                raise ValueError(
+                    f"Invalid charm name in lib {value!r}. Try replacing hyphens ('-') with underscores ('_')."
+                )
+            raise ValueError(
+                f"Invalid charm name for lib {value!r}. Value {charm_name!r} is invalid."
+            )
+        if not re.fullmatch("[a-z0-9_]+", lib_name):
+            raise ValueError(f"Library name {lib_name!r} is invalid.")
+        return str(value)
+
+    @pydantic.validator("version", pre=True)
+    def _validate_api_version(cls, value: str) -> str:
+        """Validate the API version field, providing a useful error message on failure."""
+        api, *_ = str(value).partition(".")
+        try:
+            int(api)
+        except ValueError:
+            raise ValueError(f"API version not valid. Expected an integer, got {api!r}") from None
+        return str(value)
+
+    @pydantic.validator("version", pre=True)
+    def _validate_patch_version(cls, value: str) -> str:
+        """Validate the optional patch version, providing a useful error message."""
+        api, separator, patch = value.partition(".")
+        if not separator:
+            return value
+        try:
+            int(patch)
+        except ValueError:
+            raise ValueError(
+                f"Patch version not valid. Expected an integer, got {patch!r}"
+            ) from None
+        return value
+
+    @property
+    def api_version(self) -> int:
+        """The API version needed for this library."""
+        return int(self.version.partition(".")[0])
+
+    @property
+    def patch_version(self) -> int | None:
+        """The patch version needed for this library, or None if no patch version is specified."""
+        api, _, patch = self.version.partition(".")
+        if not patch:
+            return None
+        return int(patch)
+
+
 @dataclasses.dataclass
 class CharmBuildInfo(models.BuildInfo):
     """Information about a single build option, with charmcraft-specific info.
@@ -381,6 +452,9 @@ class CharmcraftProject(models.Project, metaclass=abc.ABCMeta):
     contact: None = None
     issues: None = None
     source_code: None = None
+    charm_libs: list[CharmLib] = pydantic.Field(
+        default_factory=list, title="List of libraries to use for this charm"
+    )
 
     # These private attributes are not part of the project model but are attached here
     # because Charmcraft uses this metadata.
diff --git a/charmcraft/services/store.py b/charmcraft/services/store.py
index b6c299462..785a9da0b 100644
--- a/charmcraft/services/store.py
+++ b/charmcraft/services/store.py
@@ -17,14 +17,16 @@
 from __future__ import annotations
 
 import platform
-from collections.abc import Collection, Sequence
+from collections.abc import Collection, Mapping, Sequence
 
 import craft_application
 import craft_store
 from craft_store import models
 
-from charmcraft import const, env, errors
+from charmcraft import const, env, errors, store
+from charmcraft.models import CharmLib
 from charmcraft.store import AUTH_DEFAULT_PERMISSIONS, AUTH_DEFAULT_TTL
+from charmcraft.store.models import Library, LibraryMetadataRequest
 
 
 class BaseStoreService(craft_application.AppService):
@@ -33,6 +35,7 @@ class BaseStoreService(craft_application.AppService):
     This service should be easily adjustable for craft-application.
     """
 
+    ClientClass: type[craft_store.StoreClient] = craft_store.StoreClient
     client: craft_store.StoreClient
     _endpoints: craft_store.endpoints.Endpoints = craft_store.endpoints.CHARMHUB
     _environment_auth: str = const.ALTERNATE_AUTH_ENV_VAR
@@ -73,7 +76,7 @@ def setup(self) -> None:
         """Set up the store service."""
         super().setup()
 
-        self.client = craft_store.StoreClient(
+        self.client = self.ClientClass(
             application_name=self._app.name,
             base_url=self._base_url,
             storage_base_url=self._storage_url,
@@ -159,6 +162,9 @@ def get_credentials(
 class StoreService(BaseStoreService):
     """A Store service specifically for Charmcraft."""
 
+    ClientClass = store.Client
+    client: store.Client  # pyright: ignore[reportIncompatibleVariableOverride]
+
     def set_resource_revisions_architectures(
         self, name: str, resource_name: str, updates: dict[int, list[str]]
     ) -> Collection[models.resource_revision_model.CharmResourceRevision]:
@@ -182,3 +188,42 @@ def set_resource_revisions_architectures(
         )
         new_revisions = self.client.list_resource_revisions(name=name, resource_name=resource_name)
         return [rev for rev in new_revisions if int(rev.revision) in updates]
+
+    def get_libraries_metadata(self, libraries: Sequence[CharmLib]) -> Sequence[Library]:
+        """Get the metadata for one or more charm libraries.
+
+        :param libraries: A sequence of libraries to request.
+        :returns: A sequence of the libraries' metadata in the store.
+        """
+        store_libs = []
+        for lib in libraries:
+            charm_name, _, lib_name = lib.lib.partition(".")
+            store_lib = LibraryMetadataRequest(
+                {
+                    "charm-name": charm_name,
+                    "library-name": lib_name,
+                    "api": lib.api_version,
+                }
+            )
+            if (patch_version := lib.patch_version) is not None:
+                store_lib["patch"] = patch_version
+            store_libs.append(store_lib)
+
+        return self.client.fetch_libraries_metadata(store_libs)
+
+    def get_libraries_metadata_by_name(
+        self, libraries: Sequence[CharmLib]
+    ) -> Mapping[str, Library]:
+        """Get a mapping of [charm_name].[library_name] to the requested libraries."""
+        return {
+            f"{lib.charm_name}.{lib.lib_name}": lib
+            for lib in self.get_libraries_metadata(libraries)
+        }
+
+    def get_library(
+        self, charm_name: str, *, library_id: str, api: int | None = None, patch: int | None = None
+    ) -> Library:
+        """Get a library by charm name and ID from charmhub."""
+        return self.client.get_library(
+            charm_name=charm_name, library_id=library_id, api=api, patch=patch
+        )
diff --git a/charmcraft/store/__init__.py b/charmcraft/store/__init__.py
index 0e4d3597c..5bf9cc4d4 100644
--- a/charmcraft/store/__init__.py
+++ b/charmcraft/store/__init__.py
@@ -17,6 +17,7 @@
 
 from charmcraft.store.client import build_user_agent, AnonymousClient, Client
 from charmcraft.store import models
+from charmcraft.store.models import LibraryMetadataRequest
 from charmcraft.store.registry import (
     OCIRegistry,
     HashingTemporaryFile,
@@ -37,4 +38,5 @@
     "AUTH_DEFAULT_TTL",
     "Store",
     "models",
+    "LibraryMetadataRequest",
 ]
diff --git a/charmcraft/store/client.py b/charmcraft/store/client.py
index 8d0bf44b9..54a0915df 100644
--- a/charmcraft/store/client.py
+++ b/charmcraft/store/client.py
@@ -18,6 +18,7 @@
 
 import os
 import platform
+from collections.abc import Sequence
 from json.decoder import JSONDecodeError
 from typing import Any
 
@@ -31,6 +32,7 @@
 )
 
 from charmcraft import __version__, const, utils
+from charmcraft.store.models import Library, LibraryMetadataRequest
 
 TESTING_ENV_PREFIXES = ["TRAVIS", "AUTOPKGTEST_TMP"]
 
@@ -72,17 +74,36 @@ def request_urlpath_json(self, method: str, urlpath: str, *args, **kwargs) -> di
 class Client(craft_store.StoreClient):
     """Lightweight layer above StoreClient."""
 
-    def __init__(self, api_base_url: str, storage_base_url: str, ephemeral: bool = False):
+    def __init__(
+        self,
+        api_base_url: str = "",
+        storage_base_url: str = "",
+        ephemeral: bool = False,
+        application_name: str = "charmcraft",
+        *,
+        base_url: str = "",
+        endpoints: endpoints.Endpoints = endpoints.CHARMHUB,
+        environment_auth: str = const.ALTERNATE_AUTH_ENV_VAR,
+        user_agent: str = build_user_agent(),
+    ):
+        """Initialise a Charmcraft store client.
+
+        Supports both charmcraft 2.x style init and compatibility with upstream.
+        """
+        if base_url and api_base_url or not base_url and not api_base_url:
+            raise ValueError("Either base_url or api_base_url must be set, but not both.")
+        if base_url:
+            api_base_url = base_url
         self.api_base_url = api_base_url.rstrip("/")
         self.storage_base_url = storage_base_url.rstrip("/")
 
         super().__init__(
             base_url=api_base_url,
             storage_base_url=storage_base_url,
-            endpoints=endpoints.CHARMHUB,
-            application_name="charmcraft",
-            user_agent=build_user_agent(),
-            environment_auth=const.ALTERNATE_AUTH_ENV_VAR,
+            endpoints=endpoints,
+            application_name=application_name,
+            user_agent=user_agent,
+            environment_auth=environment_auth,
             ephemeral=ephemeral,
         )
 
@@ -150,3 +171,37 @@ def _storage_push(self, monitor) -> requests.Response:
             headers={"Content-Type": monitor.content_type, "Accept": "application/json"},
             data=monitor,
         )
+
+    def get_library(
+        self, *, charm_name: str, library_id: str, api: int | None = None, patch: int | None = None
+    ) -> Library:
+        """Fetch a library attached to a charm.
+
+        http://api.charmhub.io/docs/libraries.html#fetch_library
+        """
+        params = {}
+        if api is not None:
+            params["api"] = api
+        if patch is not None:
+            params["patch"] = patch
+        return Library.from_dict(
+            self.request_urlpath_json(
+                "GET",
+                f"/v1/charm/libraries/{charm_name}/{library_id}",
+                params=params,
+            )
+        )
+
+    def fetch_libraries_metadata(
+        self, libs: Sequence[LibraryMetadataRequest]
+    ) -> Sequence[Library]:
+        """Fetch the metadata for one or more charm libraries.
+
+        http://api.charmhub.io/docs/libraries.html#fetch_libraries
+        """
+        response = self.request_urlpath_json("POST", "/v1/charm/libraries/bulk", json=libs)
+        if "libraries" not in response:
+            raise CraftError(
+                "Server returned invalid response while querying libraries", details=str(response)
+            )
+        return [Library.from_dict(lib) for lib in response["libraries"]]
diff --git a/charmcraft/store/models.py b/charmcraft/store/models.py
index dba16702e..a2bab62bb 100644
--- a/charmcraft/store/models.py
+++ b/charmcraft/store/models.py
@@ -20,9 +20,10 @@
 import enum
 import functools
 from dataclasses import dataclass
-from typing import Literal
+from typing import Any, Literal, TypedDict
 
 from craft_cli import CraftError
+from typing_extensions import NotRequired, Self
 
 
 @dataclasses.dataclass(frozen=True)
@@ -170,10 +171,7 @@ class Channel:
 
 @dataclasses.dataclass(frozen=True)
 class Library:
-    """Charmcraft-specific store library model.
-
-    Deprecated in favour of implementation in craft-store.
-    """
+    """Charmcraft-specific store library model."""
 
     lib_id: str
     lib_name: str
@@ -183,6 +181,24 @@ class Library:
     content: str | None
     content_hash: str
 
+    @classmethod
+    def from_dict(cls, value: dict[str, Any]) -> Self:
+        """Convert a dictionary of this type to the type itself.
+
+        Dictionary should match a single item of the `libraries` attribute in
+        the response to fetch_libraries or fetch_library
+        http://api.charmhub.io/docs/libraries.html#fetch_libraries
+        """
+        return cls(
+            charm_name=value["charm-name"],
+            lib_name=value["library-name"],
+            lib_id=value["library-id"],
+            api=value["api"],
+            patch=value["patch"],
+            content_hash=value["hash"],
+            content=value.get("content"),
+        )
+
 
 @dataclasses.dataclass(frozen=True)
 class RegistryCredentials:
@@ -265,3 +281,14 @@ def name(self) -> str:
         """Get the channel name as a string."""
         risk = self.risk.name.lower()
         return "/".join(i for i in (self.track, risk, self.branch) if i is not None)
+
+
+LibraryMetadataRequest = TypedDict(
+    "LibraryMetadataRequest",
+    {
+        "charm-name": str,
+        "library-name": str,
+        "api": int,
+        "patch": NotRequired[int],
+    },
+)
diff --git a/charmcraft/utils/__init__.py b/charmcraft/utils/__init__.py
index 312f032d9..f9bac33a1 100644
--- a/charmcraft/utils/__init__.py
+++ b/charmcraft/utils/__init__.py
@@ -23,6 +23,8 @@
     create_charm_name_from_importable,
     create_importable_name,
     get_lib_internals,
+    get_lib_path,
+    get_lib_module_name,
     get_lib_info,
     get_libs_from_tree,
     collect_charmlib_pydeps,
@@ -70,6 +72,8 @@
     "create_charm_name_from_importable",
     "create_importable_name",
     "get_lib_internals",
+    "get_lib_path",
+    "get_lib_module_name",
     "get_lib_info",
     "get_libs_from_tree",
     "collect_charmlib_pydeps",
diff --git a/charmcraft/utils/charmlibs.py b/charmcraft/utils/charmlibs.py
index 8640f8313..5d044e1a7 100644
--- a/charmcraft/utils/charmlibs.py
+++ b/charmcraft/utils/charmlibs.py
@@ -1,4 +1,4 @@
-# Copyright 2023 Canonical Ltd.
+# Copyright 2023-2024 Canonical Ltd.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@
 import os
 import pathlib
 from dataclasses import dataclass
+from typing import overload
 
 import yaml
 from craft_cli import CraftError
@@ -168,7 +169,35 @@ def _api_patch_validator(value):
     )
 
 
-def get_lib_info(*, full_name=None, lib_path=None):
+def get_lib_path(charm: str, lib_name: str, api: int) -> pathlib.Path:
+    """Get a relative path for a library based on its home charm, name and API version.
+
+    :param charm: The name of the charm that owns this library
+    :param lib_name: The name of the library
+    :param api: The API version of the library
+    :returns: A relative path to the library python file.
+    """
+    return (
+        pathlib.Path("lib/charms") / create_importable_name(charm) / f"v{api}" / f"{lib_name}.py"
+    )
+
+
+def get_lib_module_name(charm: str, lib_name: str, api: int) -> str:
+    """Get a Python module path for a library based on its home charm, name and API version.
+
+    :param charm: The name of the charm that owns this library
+    :param lib_name: The name of the library
+    :param api: The API version of the library
+    :returns: A string of the full path to the charm.
+    """
+    return f"charms.{create_importable_name(charm)}.v{api}.{lib_name}"
+
+
+@overload
+def get_lib_info(*, full_name: str) -> LibData: ...
+@overload
+def get_lib_info(*, lib_path: pathlib.Path) -> LibData: ...
+def get_lib_info(*, full_name: str | None = None, lib_path: pathlib.Path | None = None) -> LibData:
     """Get the whole lib info from the path/file.
 
     This will perform mutation of the charm name to create importable paths.
@@ -178,7 +207,7 @@ def get_lib_info(*, full_name=None, lib_path=None):
 
     This function needs to be called standing on the root directory of the project.
     """
-    if full_name is None:
+    if lib_path:
         # get it from the lib_path
         try:
             libsdir, charmsdir, importable_charm_name, v_api = lib_path.parts[:-1]
@@ -187,8 +216,7 @@ def get_lib_info(*, full_name=None, lib_path=None):
         if libsdir != "lib" or charmsdir != "charms" or lib_path.suffix != ".py":
             raise errors.BadLibraryPathError(lib_path)
         full_name = ".".join((charmsdir, importable_charm_name, v_api, lib_path.stem))
-
-    else:
+    elif full_name:
         # build the path! convert a lib name with dots to the full path, including lib
         # dir and Python extension.
         #    e.g.: charms.mycharm.v4.foo -> lib/charms/mycharm/v4/foo.py
@@ -204,6 +232,8 @@ def get_lib_info(*, full_name=None, lib_path=None):
             raise errors.BadLibraryNameError(full_name)
         path = pathlib.Path("lib")
         lib_path = path / charmsdir / importable_charm_name / v_api / (libfile + ".py")
+    else:
+        raise TypeError("get_lib_info needs either a full name or a lib path")
 
     # charm names in the path can contain '_' to be importable
     # these should be '-', so change them back
diff --git a/tests/commands/test_store_client.py b/tests/commands/test_store_client.py
index 36f65c152..4dfa78607 100644
--- a/tests/commands/test_store_client.py
+++ b/tests/commands/test_store_client.py
@@ -140,7 +140,7 @@ def test_client_init():
     with patch("craft_store.StoreClient.__init__") as mock_client_init:
         with patch("charmcraft.store.client.build_user_agent") as mock_ua:
             mock_ua.return_value = user_agent
-            Client(api_url, storage_url)
+            Client(api_url, storage_url, user_agent=user_agent)
     mock_client_init.assert_called_with(
         base_url=api_url,
         storage_base_url=storage_url,
diff --git a/tests/conftest.py b/tests/conftest.py
index 170b28484..679eaf76c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -26,7 +26,6 @@
 from unittest.mock import Mock
 
 import craft_parts
-import craft_store
 import pytest
 import responses as responses_module
 import yaml
@@ -35,7 +34,7 @@
 from craft_providers import Executor, Provider, bases
 
 import charmcraft.parts
-from charmcraft import const, deprecations, instrum, parts, services, utils
+from charmcraft import const, deprecations, instrum, parts, services, store, utils
 from charmcraft.application.main import APP_METADATA
 from charmcraft.bases import get_host_as_base
 from charmcraft.models import charmcraft as config_module
@@ -67,7 +66,7 @@ def service_factory(
 
     factory.project = simple_charm
 
-    factory.store.client = mock.Mock(spec_set=craft_store.StoreClient)
+    factory.store.client = mock.Mock(spec_set=store.Client)
 
     return factory
 
diff --git a/tests/unit/commands/test_store.py b/tests/unit/commands/test_store.py
index 78b34aef4..ee76f93b4 100644
--- a/tests/unit/commands/test_store.py
+++ b/tests/unit/commands/test_store.py
@@ -14,16 +14,26 @@
 #
 # For further info, check https://github.com/canonical/charmcraft
 """Unit tests for store commands."""
+import argparse
 import datetime
 import textwrap
 
+import craft_cli.pytest_plugin
 import pytest
 from craft_store import models
 
+from charmcraft import errors, store
 from charmcraft.application.commands import SetResourceArchitecturesCommand
+from charmcraft.application.commands.store import FetchLibs
+from charmcraft.application.main import APP_METADATA
+from charmcraft.models.project import CharmLib
 from charmcraft.utils import cli
 from tests import get_fake_revision
 
+BASIC_CHARMCRAFT_YAML = """\
+type: charm
+"""
+
 
 @pytest.mark.parametrize(
     ("updates", "expected"),
@@ -72,3 +82,139 @@ def test_set_resource_architectures_output_table(emitter, updates, expected):
     SetResourceArchitecturesCommand.write_output(cli.OutputFormat.TABLE, updates)
 
     emitter.assert_message(expected)
+
+
+def test_fetch_libs_no_charm_libs(
+    emitter: craft_cli.pytest_plugin.RecordingEmitter, service_factory
+):
+    fetch_libs = FetchLibs({"app": APP_METADATA, "services": service_factory})
+
+    with pytest.raises(errors.LibraryError) as exc_info:
+        fetch_libs.run(argparse.Namespace())
+
+    assert exc_info.value.resolution == "Add a 'charm-libs' section to charmcraft.yaml."
+
+
+@pytest.mark.parametrize(
+    ("libs", "expected"),
+    [
+        (
+            [CharmLib(lib="mysql.mysql", version="1")],
+            textwrap.dedent(
+                """\
+                Could not find the following libraries on charmhub:
+                - lib: mysql.mysql
+                  version: '1'
+                """
+            ),
+        ),
+        (
+            [
+                CharmLib(lib="mysql.mysql", version="1"),
+                CharmLib(lib="some_charm.lib", version="1.2"),
+            ],
+            textwrap.dedent(
+                """\
+                Could not find the following libraries on charmhub:
+                - lib: mysql.mysql
+                  version: '1'
+                - lib: some_charm.lib
+                  version: '1.2'
+                """
+            ),
+        ),
+    ],
+)
+def test_fetch_libs_missing_from_store(service_factory, libs, expected):
+    service_factory.project.charm_libs = libs
+    service_factory.store.client.fetch_libraries_metadata.return_value = []
+    fetch_libs = FetchLibs({"app": APP_METADATA, "services": service_factory})
+
+    with pytest.raises(errors.CraftError) as exc_info:
+        fetch_libs.run(argparse.Namespace())
+
+    assert exc_info.value.args[0] == expected
+
+
+@pytest.mark.parametrize(
+    ("libs", "store_libs", "dl_lib", "expected"),
+    [
+        (
+            [CharmLib(lib="mysql.backups", version="1")],
+            [
+                store.models.Library(
+                    charm_name="mysql",
+                    lib_name="backups",
+                    lib_id="ididid",
+                    api=1,
+                    patch=2,
+                    content=None,
+                    content_hash="hashhashhash",
+                )
+            ],
+            store.models.Library(
+                charm_name="mysql",
+                lib_name="backups",
+                lib_id="ididid",
+                api=1,
+                patch=2,
+                content=None,
+                content_hash="hashhashhash",
+            ),
+            "Store returned no content for 'mysql.backups'",
+        ),
+    ],
+)
+def test_fetch_libs_no_content(new_path, service_factory, libs, store_libs, dl_lib, expected):
+    service_factory.project.charm_libs = libs
+    service_factory.store.client.fetch_libraries_metadata.return_value = store_libs
+    service_factory.store.client.get_library.return_value = dl_lib
+    fetch_libs = FetchLibs({"app": APP_METADATA, "services": service_factory})
+
+    with pytest.raises(errors.CraftError, match=expected) as exc_info:
+        fetch_libs.run(argparse.Namespace())
+
+    assert exc_info.value.args[0] == expected
+
+
+@pytest.mark.parametrize(
+    ("libs", "store_libs", "dl_lib", "expected"),
+    [
+        (
+            [CharmLib(lib="mysql.backups", version="1")],
+            [
+                store.models.Library(
+                    charm_name="mysql",
+                    lib_name="backups",
+                    lib_id="ididid",
+                    api=1,
+                    patch=2,
+                    content=None,
+                    content_hash="hashhashhash",
+                )
+            ],
+            store.models.Library(
+                charm_name="mysql",
+                lib_name="backups",
+                lib_id="ididid",
+                api=1,
+                patch=2,
+                content="I am a library.",
+                content_hash="hashhashhash",
+            ),
+            "Store returned no content for 'mysql.backups'",
+        ),
+    ],
+)
+def test_fetch_libs_success(
+    new_path, emitter, service_factory, libs, store_libs, dl_lib, expected
+):
+    service_factory.project.charm_libs = libs
+    service_factory.store.client.fetch_libraries_metadata.return_value = store_libs
+    service_factory.store.client.get_library.return_value = dl_lib
+    fetch_libs = FetchLibs({"app": APP_METADATA, "services": service_factory})
+
+    fetch_libs.run(argparse.Namespace())
+
+    emitter.assert_progress("Getting library metadata from charmhub")
+    emitter.assert_message("Downloaded 1 charm libraries.")
diff --git a/tests/unit/models/test_project.py b/tests/unit/models/test_project.py
index 08a5873a8..f4c2cc457 100644
--- a/tests/unit/models/test_project.py
+++ b/tests/unit/models/test_project.py
@@ -20,6 +20,7 @@
 from textwrap import dedent
 from typing import Any
 
+import hypothesis
 import pydantic
 import pyfakefs.fake_filesystem
 import pytest
@@ -29,6 +30,7 @@
 from craft_application.util import safe_yaml_load
 from craft_cli import CraftError
 from craft_providers import bases
+from hypothesis import strategies
 
 from charmcraft import const, utils
 from charmcraft.models import project
@@ -190,6 +192,67 @@ def test_build_info_from_build_on_run_on_basic(
     pytest_check.equal(info.base.version, build_on_base.channel)
 
 
+@pytest.mark.parametrize(
+    "lib_name",
+    ["charm.lib", "charm_with_hyphens.lib", "charm.lib_with_hyphens", "charm0.number_0_lib"],
+)
+@pytest.mark.parametrize("lib_version", ["0", "1", "2.0", "2.1", "3.14"])
+def test_create_valid_charm_lib(lib_name, lib_version):
+    project.CharmLib.unmarshal({"lib": lib_name, "version": lib_version})
+
+
+@pytest.mark.parametrize(
+    ("name", "error_match"),
+    [
+        ("boop", r"Library name invalid. Expected '\[charm_name\].\[lib_name\]', got 'boop'"),
+        (
+            "raw-charm-name.valid_lib",
+            r"Invalid charm name in lib 'raw-charm-name.valid_lib'. Try replacing hyphens \('-'\) with underscores \('_'\).",
+        ),
+        (
+            "Invalid charm name.valid_lib",
+            "Invalid charm name for lib 'Invalid charm name.valid_lib'. Value 'Invalid charm name' is invalid",
+        ),
+        ("my_charm.invalid library name", "Library name 'invalid library name' is invalid."),
+    ],
+)
+def test_invalid_charm_lib_name(name: str, error_match: str):
+    with pytest.raises(pydantic.ValidationError, match=error_match):
+        project.CharmLib.unmarshal({"lib": name, "version": "0"})
+
+
+@hypothesis.given(
+    strategies.one_of(
+        strategies.floats(
+            min_value=0.001,
+            max_value=2**32,
+            allow_nan=False,
+            allow_infinity=False,
+            allow_subnormal=False,
+        ),
+        strategies.integers(min_value=0, max_value=2**32),
+    )
+)
+def test_valid_library_version(version: float):
+    project.CharmLib.unmarshal({"lib": "charm_name.lib_name", "version": str(version)})
+
+
+@pytest.mark.parametrize("version", [".1", "NaN", ""])
+def test_invalid_api_version(version: str):
+    with pytest.raises(
+        pydantic.ValidationError, match="API version not valid. Expected an integer, got '"
+    ):
+        project.CharmLib(lib="charm_name.lib_name", version=version)
+
+
+@pytest.mark.parametrize("version", ["1.", "1.number"])
+def test_invalid_patch_version(version: str):
+    with pytest.raises(
+        pydantic.ValidationError, match="Patch version not valid. Expected an integer, got '"
+    ):
+        project.CharmLib(lib="charm_name.lib_name", version=version)
+
+
 @pytest.mark.parametrize(
     ("run_on", "expected"),
     [
diff --git a/tests/unit/models/valid_charms_yaml/full-bases.yaml b/tests/unit/models/valid_charms_yaml/full-bases.yaml
index b6261af65..170fafd8d 100644
--- a/tests/unit/models/valid_charms_yaml/full-bases.yaml
+++ b/tests/unit/models/valid_charms_yaml/full-bases.yaml
@@ -24,6 +24,11 @@ parts:
     charm-strict-dependencies: false
   another-part:
     plugin: nil
+charm-libs:
+  - lib: my_charm.my_lib
+    version: '1'
+  - lib: other_charm.lib
+    version: '0.123'
 bases:
 - build-on:
   - name: ubuntu
diff --git a/tests/unit/models/valid_charms_yaml/full-platforms.yaml b/tests/unit/models/valid_charms_yaml/full-platforms.yaml
index 2a709f95b..855e44561 100644
--- a/tests/unit/models/valid_charms_yaml/full-platforms.yaml
+++ b/tests/unit/models/valid_charms_yaml/full-platforms.yaml
@@ -24,6 +24,11 @@ parts:
     charm-strict-dependencies: false
   another-part:
     plugin: nil
+charm-libs:
+  - lib: my_charm.my_lib
+    version: '1'
+  - lib: other_charm.lib
+    version: '0.123'
 base: ubuntu@24.04
 build-base: ubuntu@devel
 platforms:
diff --git a/tests/unit/services/test_store.py b/tests/unit/services/test_store.py
index df72dbb04..ec4730d07 100644
--- a/tests/unit/services/test_store.py
+++ b/tests/unit/services/test_store.py
@@ -26,13 +26,15 @@
 
 import charmcraft
 from charmcraft import application, errors, services
+from charmcraft.models.project import CharmLib
+from charmcraft.store import client
 from tests import get_fake_revision
 
 
 @pytest.fixture()
-def store():
-    store = services.StoreService(app=application.APP_METADATA, services=None)
-    store.client = mock.Mock(spec_set=craft_store.StoreClient)
+def store(service_factory) -> services.StoreService:
+    store = services.StoreService(app=application.APP_METADATA, services=service_factory)
+    store.client = mock.Mock(spec_set=client.Client)
     return store
 
 
@@ -222,3 +224,24 @@ def test_get_credentials(monkeypatch, store):
         packages=None,
         channels=None,
     )
+
+
+@pytest.mark.parametrize(
+    ("libs", "expected_call"),
+    [
+        ([], []),
+        (
+            [CharmLib(lib="my_charm.my_lib", version="1")],
+            [{"charm-name": "my_charm", "library-name": "my_lib", "api": 1}],
+        ),
+        (
+            [CharmLib(lib="my_charm.my_lib", version="1.0")],
+            [{"charm-name": "my_charm", "library-name": "my_lib", "api": 1, "patch": 0}],
+        ),
+    ],
+)
+def test_fetch_libraries_metadata(monkeypatch, store, libs, expected_call):
+
+    store.get_libraries_metadata(libs)
+
+    store.client.fetch_libraries_metadata.assert_called_once_with(expected_call)
diff --git a/tests/unit/store/test_client.py b/tests/unit/store/test_client.py
new file mode 100644
index 000000000..146a02ed0
--- /dev/null
+++ b/tests/unit/store/test_client.py
@@ -0,0 +1,109 @@
+# Copyright 2024 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# For further info, check https://github.com/canonical/charmcraft
+"""Unit tests for store client."""
+
+from unittest import mock
+
+import pytest
+
+from charmcraft import store
+
+
+@pytest.fixture()
+def client() -> store.Client:
+    return store.Client(api_base_url="http://charmhub.local")
+
+
+@pytest.mark.parametrize(
+    ("charm", "lib_id", "api", "patch", "expected_call"),
+    [
+        (
+            "my-charm",
+            "abcdefg",
+            None,
+            None,
+            mock.call("GET", "/v1/charm/libraries/my-charm/abcdefg", params={}),
+        ),
+        (
+            "my-charm",
+            "abcdefg",
+            0,
+            0,
+            mock.call(
+                "GET", "/v1/charm/libraries/my-charm/abcdefg", params={"api": 0, "patch": 0}
+            ),
+        ),
+    ],
+)
+def test_get_library_success(monkeypatch, client, charm, lib_id, api, patch, expected_call):
+    mock_get_urlpath_json = mock.Mock(
+        return_value={
+            "charm-name": charm,
+            "library-name": "my_lib",
+            "library-id": lib_id,
+            "api": api or 1,
+            "patch": patch or 2,
+            "hash": "hashy!",
+        }
+    )
+    monkeypatch.setattr(client, "request_urlpath_json", mock_get_urlpath_json)
+
+    client.get_library(charm_name=charm, library_id=lib_id, api=api, patch=patch)
+
+    mock_get_urlpath_json.assert_has_calls([expected_call])
+
+
+@pytest.mark.parametrize(
+    ("libs", "json_response", "expected"),
+    [
+        ([], {"libraries": []}, []),
+        (
+            [{"charm-name": "my-charm", "library-name": "my_lib"}],
+            {
+                "libraries": [
+                    {
+                        "charm-name": "my-charm",
+                        "library-name": "my_lib",
+                        "library-id": "ididid",
+                        "api": 1,
+                        "patch": 2,
+                        "hash": "hashhashhash",
+                    },
+                ],
+            },
+            [
+                store.models.Library(
+                    charm_name="my-charm",
+                    lib_name="my_lib",
+                    lib_id="ididid",
+                    api=1,
+                    patch=2,
+                    content=None,
+                    content_hash="hashhashhash",
+                ),
+            ],
+        ),
+    ],
+)
+def test_fetch_libraries_metadata(monkeypatch, client, libs, json_response, expected):
+    mock_get_urlpath_json = mock.Mock(return_value=json_response)
+    monkeypatch.setattr(client, "request_urlpath_json", mock_get_urlpath_json)
+
+    assert client.fetch_libraries_metadata(libs) == expected
+
+    mock_get_urlpath_json.assert_has_calls(
+        [mock.call("POST", "/v1/charm/libraries/bulk", json=libs)]
+    )
diff --git a/tests/unit/store/test_models.py b/tests/unit/store/test_models.py
new file mode 100644
index 000000000..04b9de198
--- /dev/null
+++ b/tests/unit/store/test_models.py
@@ -0,0 +1,68 @@
+# Copyright 2024 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# For further info, check https://github.com/canonical/charmcraft
+"""Tests for store models."""
+
+import pytest
+
+from charmcraft.store import models
+
+
+@pytest.mark.parametrize(
+    ("data", "expected"),
+    [
+        (
+            {
+                "charm-name": "abc",
+                "library-name": "def",
+                "library-id": "id",
+                "api": 1,
+                "patch": 123,
+                "hash": "hashyhash",
+            },
+            models.Library(
+                charm_name="abc",
+                lib_name="def",
+                lib_id="id",
+                api=1,
+                patch=123,
+                content_hash="hashyhash",
+                content=None,
+            ),
+        ),
+        (
+            {
+                "charm-name": "abc",
+                "library-name": "def",
+                "library-id": "id",
+                "api": 1,
+                "patch": 123,
+                "hash": "hashyhash",
+                "content": "I am a library.",
+            },
+            models.Library(
+                charm_name="abc",
+                lib_name="def",
+                lib_id="id",
+                api=1,
+                patch=123,
+                content_hash="hashyhash",
+                content="I am a library.",
+            ),
+        ),
+    ],
+)
+def test_library_from_dict(data, expected):
+    assert models.Library.from_dict(data) == expected
diff --git a/tests/unit/utils/test_charmlibs.py b/tests/unit/utils/test_charmlibs.py
index 9ff02fb97..34a678df2 100644
--- a/tests/unit/utils/test_charmlibs.py
+++ b/tests/unit/utils/test_charmlibs.py
@@ -1,4 +1,4 @@
-# Copyright 2023 Canonical Ltd.
+# Copyright 2023-2024 Canonical Ltd.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -27,6 +27,8 @@
     collect_charmlib_pydeps,
     get_lib_info,
     get_lib_internals,
+    get_lib_module_name,
+    get_lib_path,
     get_libs_from_tree,
     get_name_from_metadata,
 )
@@ -79,6 +81,26 @@ def test_get_name_from_metadata_bad_content_no_name(tmp_path, monkeypatch):
     assert result is None
 
 
+@pytest.mark.parametrize(
+    ("charm", "lib", "api", "expected"),
+    [
+        ("my-charm", "some_lib", 0, pathlib.Path("lib/charms/my_charm/v0/some_lib.py")),
+    ],
+)
+def test_get_lib_path(charm: str, lib: str, api: int, expected: pathlib.Path):
+    assert get_lib_path(charm, lib, api) == expected
+
+
+@pytest.mark.parametrize(
+    ("charm", "lib", "api", "expected"),
+    [
+        ("my-charm", "some_lib", 0, "charms.my_charm.v0.some_lib"),
+    ],
+)
+def test_get_lib_module_name(charm: str, lib: str, api: int, expected: str):
+    assert get_lib_module_name(charm, lib, api) == expected
+
+
 # endregion
 # region getlibinfo tests