From 94b482f0bdd24e712a546f7351b74b14f3ac2ad6 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 16 Mar 2026 10:26:50 +0000
Subject: [PATCH 1/4] Initial plan


From ca8e19b2472aac1aba5367ac1a6d65e4f144339b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 16 Mar 2026 10:35:02 +0000
Subject: [PATCH 2/4] Add filesystem parameter to cf.read as pass-through to
 cfdm.read

Co-authored-by: bnlawrence <1792815+bnlawrence@users.noreply.github.com>
---
 cf/docstring/docstring.py | 15 +++++++++++++++
 cf/read_write/read.py     |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/cf/docstring/docstring.py b/cf/docstring/docstring.py
index dfd65e28d1..cbb15f46e1 100644
--- a/cf/docstring/docstring.py
+++ b/cf/docstring/docstring.py
@@ -686,4 +686,19 @@
                      The subspace is the smallest hyperrectangular
                      subspace that contains all of the selected
                      locations.""",
+    # read filesystem
+    "{{read filesystem: optional}}": """filesystem: optional
+            A pre-authenticated filesystem object (for example an
+            ``fsspec`` filesystem instance) to use for opening the
+            dataset. When provided, *datasets* values are treated as
+            paths understood by *filesystem*, and local string
+            pre-processing (tilde/variable expansion, globbing and
+            directory walking) is bypassed. The file is opened by
+            calling ``filesystem.open(dataset, "rb")``, which returns
+            a file-like object that is passed to the netCDF backend.
+
+            If `None` (the default) then the existing file-opening
+            logic is used.
+
+            .. versionadded:: NEXTVERSION""",
 }
diff --git a/cf/read_write/read.py b/cf/read_write/read.py
index c920b72b97..1a6e95b0c8 100644
--- a/cf/read_write/read.py
+++ b/cf/read_write/read.py
@@ -336,6 +336,10 @@ class read(cfdm.read):
 
             .. versionadded:: 3.19.0
 
+        {{read filesystem: optional}}
+
+            .. versionadded:: NEXTVERSION
+
         umversion: deprecated at version 3.0.0
             Use the *um* parameter instead.
 
@@ -455,6 +459,7 @@ def __new__(
         fmt=None,
         file_type=None,
         group_dimension_search="closest_ancestor",
+        filesystem=None,
     ):
         """Read field or domain constructs from a dataset."""
         kwargs = locals()

From ddc4840f3a760d87566640ee653c0e71bb2e21dc Mon Sep 17 00:00:00 2001
From: David Hassell <davidhassell@users.noreply.github.com>
Date: Wed, 18 Mar 2026 17:17:01 +0000
Subject: [PATCH 3/4] Remove duplicate docstring

---
 cf/docstring/docstring.py | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/cf/docstring/docstring.py b/cf/docstring/docstring.py
index cbb15f46e1..dfd65e28d1 100644
--- a/cf/docstring/docstring.py
+++ b/cf/docstring/docstring.py
@@ -686,19 +686,4 @@
                      The subspace is the smallest hyperrectangular
                      subspace that contains all of the selected
                      locations.""",
-    # read filesystem
-    "{{read filesystem: optional}}": """filesystem: optional
-            A pre-authenticated filesystem object (for example an
-            ``fsspec`` filesystem instance) to use for opening the
-            dataset. When provided, *datasets* values are treated as
-            paths understood by *filesystem*, and local string
-            pre-processing (tilde/variable expansion, globbing and
-            directory walking) is bypassed. The file is opened by
-            calling ``filesystem.open(dataset, "rb")``, which returns
-            a file-like object that is passed to the netCDF backend.
-
-            If `None` (the default) then the existing file-opening
-            logic is used.
-
-            .. versionadded:: NEXTVERSION""",
 }

From 587ca4634d21a996800a93c5191f01ced61511b0 Mon Sep 17 00:00:00 2001
From: David Hassell <david.hassell@ncas.ac.uk>
Date: Wed, 18 Mar 2026 17:18:49 +0000
Subject: [PATCH 4/4] filesystem changelog

---
 Changelog.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Changelog.rst b/Changelog.rst
index fcc3fbb2de..674bd687f7 100644
--- a/Changelog.rst
+++ b/Changelog.rst
@@ -3,6 +3,8 @@ Version NEXTVERSION
 
 **2026-??-??**
 
+* New keyword to `cf.read`: ``filesystem``
+  (https://github.com/NCAS-CMS/cf-python/issues/931)
 * New keyword parameter to `cf.Data.compute`: ``persist``
   (https://github.com/NCAS-CMS/cf-python/issues/929)
 * New function to control the persistence of computed data: