diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba592d0b2..c8c4dde1d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ All notable changes to Get Physics Done are documented here.
 
 ## vNEXT
 
+- Bound the `mcp` dependency to `>=1.27.0,<2`. mcp 2.x removed `mcp.server.fastmcp`, so fresh installs without the `arxiv` extra, including `npx -y get-physics-done`, resolved mcp 2.x and seven built-in MCP servers failed to import (#273).
 - Add pandoc-driven markdown→LaTeX pipeline for the paper writer. Sections can opt in via `Section.content_format="markdown"`; raw-LaTeX payloads still pass through unchanged. Pandoc is probed once per `render_paper` call and shared across sections. When pandoc is missing the markdown path raises `PandocNotAvailable` with a recovery hint; legacy `maybe_convert_to_latex` callers degrade to pass-through. `--natbib` is the default so `@key` / `[@k1; @k2]` emit `\citet`/`\citep` for the template's `\bibliography{…}` to resolve; `pandoc-crossref` is auto-enabled when installed and `pandoc-citeproc` is intentionally excluded from auto-detection.
 - Fix Nature template citation rendering: switch from `naturemag.bst` to `unsrtnat` with `\usepackage[numbers,super,sort&compress]{natbib}`. `naturemag.bst` predates natbib and has no author-name macro, so pandoc's `\citet` rendered as "(author?)" in the final PDF while passing every string-level `.tex` assertion.
 - Fix PRL template cite-command resolution under revtex4-2: pass `natbib` as a class option (`\documentclass[…,natbib]{revtex4-2}`) instead of `\usepackage{natbib}`, which would otherwise option-clash with revtex's internal natbib load.
diff --git a/pyproject.toml b/pyproject.toml
index b6cff3adb..ff367cb1c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,7 +35,9 @@ dependencies = [
     "rich>=15.0.0",
     "pydantic>=2.13.3",
     "PyYAML>=6.0.3",
-    "mcp>=1.27.0",
+    # mcp 2.x removed `mcp.server.fastmcp`, which seven of the built-in
+    # servers import. Keep the 1.x API until they are ported.
+    "mcp>=1.27.0,<2",
     # Utilities
     "pybtex>=0.25.1",
     "Pillow>=12.1.1",
diff --git a/tests/test_release_consistency.py b/tests/test_release_consistency.py
index aab7029ea..a4574299b 100644
--- a/tests/test_release_consistency.py
+++ b/tests/test_release_consistency.py
@@ -1475,7 +1475,7 @@ def test_public_runtime_dependency_surface_stays_curated() -> None:
     optional = project.get("optional-dependencies", {})
 
     assert _normalized_dependency_names(dependencies) == _expected_runtime_dependency_names()
-    assert "mcp>=1.27.0" in dependencies
+    assert "mcp>=1.27.0,<2" in dependencies
     assert not any(item.startswith("mcp[") for item in dependencies)
     assert optional == _EXPECTED_OPTIONAL_DEPENDENCIES
 
@@ -1493,7 +1493,7 @@ def test_uv_lock_tracks_runtime_dependency_extras() -> None:
 
     assert [item for item in dependencies if isinstance(item, dict) and item.get("name") == "mcp"] == [{"name": "mcp"}]
     assert [item for item in requires_dist if isinstance(item, dict) and item.get("name") == "mcp"] == [
-        {"name": "mcp", "specifier": ">=1.27.0"}
+        {"name": "mcp", "specifier": ">=1.27.0,<2"}
     ]
 
 
diff --git a/uv.lock b/uv.lock
index 902393ddb..8c4a9e08e 100644
--- a/uv.lock
+++ b/uv.lock
@@ -711,7 +711,7 @@ requires-dist = [
     { name = "cairosvg", marker = "extra == 'paper'", specifier = ">=2.7.0" },
     { name = "httpx", marker = "extra == 'arxiv'", specifier = ">=0.27" },
     { name = "jinja2", specifier = ">=3.1.6" },
-    { name = "mcp", specifier = ">=1.27.0" },
+    { name = "mcp", specifier = ">=1.27.0,<2" },
     { name = "pillow", specifier = ">=12.1.1" },
     { name = "pybtex", specifier = ">=0.25.1" },
     { name = "pydantic", specifier = ">=2.13.3" },