diff --git a/src/mcgibs/client.py b/src/mcgibs/client.py
index 101aff1..a91d3ff 100644
--- a/src/mcgibs/client.py
+++ b/src/mcgibs/client.py
@@ -38,6 +38,9 @@ _INIT_RETRY_DELAYS = [2.0, 4.0, 8.0]
 # Maximum image dimensions to prevent OOM from LLM requests
 MAX_IMAGE_DIMENSION = 4096
 
+# Content types accepted for legend images (SVG is not API-compatible)
+_RASTER_IMAGE_TYPES = {"image/png", "image/jpeg", "image/gif", "image/webp"}
+
 
 class _LRUCache(OrderedDict):
     """Simple LRU cache backed by OrderedDict."""
@@ -421,13 +424,23 @@ class GIBSClient:
         layer_id: str,
         orientation: str = "horizontal",
     ) -> bytes | None:
-        """Fetch the pre-rendered legend image for a layer."""
+        """Fetch the pre-rendered legend image for a layer.
+
+        GIBS capabilities list SVG legend URLs, but PNG versions exist
+        at the same path. We prefer PNG for broad client compatibility
+        (the Anthropic API and most image viewers don't render SVG).
+        """
         layer = self.layer_index.get(layer_id)
         if layer and layer.legend_url:
+            url = layer.legend_url
+            if url.endswith(".svg"):
+                url = url[:-4] + ".png"
             try:
-                resp = await self.http.get(layer.legend_url)
+                resp = await self.http.get(url)
                 resp.raise_for_status()
-                return resp.content
+                content_type = resp.headers.get("content-type", "").split(";")[0].strip()
+                if content_type in _RASTER_IMAGE_TYPES:
+                    return resp.content
             except httpx.HTTPError:
                 pass
 
@@ -446,8 +459,8 @@ class GIBSClient:
         try:
             resp = await self.http.get(url, params=params)
             resp.raise_for_status()
-            content_type = resp.headers.get("content-type", "")
-            if content_type.startswith("image/"):
+            content_type = resp.headers.get("content-type", "").split(";")[0].strip()
+            if content_type in _RASTER_IMAGE_TYPES:
                 return resp.content
         except httpx.HTTPError as exc:
             log.debug("Legend not available for %s: %s", layer_id, exc)
diff --git a/tests/test_client.py b/tests/test_client.py
index 8e3c692..26bd44c 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -407,6 +407,74 @@ async def test_client_caches_successful_geocode(capabilities_xml):
     await client.close()
 
 
+# ---------------------------------------------------------------------------
+# Legend SVG → PNG rewriting (live API compatibility fix)
+# ---------------------------------------------------------------------------
+
+
+@respx.mock
+async def test_legend_rewrites_svg_to_png(capabilities_xml):
+    """Legend URLs ending in .svg should be rewritten to .png."""
+    # Modify the capabilities XML so AMSR2's legend URL ends in .svg
+    patched_xml = capabilities_xml.replace(
+        "AMSR2_Sea_Ice_Concentration_12km.png",
+        "AMSR2_Sea_Ice_Concentration_12km.svg",
+    )
+    respx.get(url__regex=r".*WMTSCapabilities\.xml").mock(
+        return_value=httpx.Response(200, text=patched_xml)
+    )
+
+    buf = BytesIO()
+    Image.new("RGB", (200, 20), "white").save(buf, format="PNG")
+    png_route = respx.get(url__regex=r".*legends/.*\.png").mock(
+        return_value=httpx.Response(
+            200, content=buf.getvalue(), headers={"content-type": "image/png"}
+        )
+    )
+
+    client = GIBSClient()
+    await client.initialize()
+
+    result = await client.get_legend_image("AMSR2_Sea_Ice_Concentration_12km_Monthly")
+    assert result is not None
+    # Verify the .png URL was requested, not .svg
+    assert png_route.call_count == 1
+    assert ".png" in str(png_route.calls.last.request.url)
+
+    await client.close()
+
+
+@respx.mock
+async def test_legend_rejects_svg_content(capabilities_xml):
+    """If the legend URL returns SVG content, it should be rejected."""
+    respx.get(url__regex=r".*WMTSCapabilities\.xml").mock(
+        return_value=httpx.Response(200, text=capabilities_xml)
+    )
+    respx.get(url__regex=r".*legends/.*\.png").mock(
+        return_value=httpx.Response(
+            200,
+            content=b'<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"...',
+            headers={"content-type": "image/svg+xml"},
+        )
+    )
+    # WMS fallback also returns non-image
+    respx.get(url__regex=r".*wms\.cgi.*").mock(
+        return_value=httpx.Response(
+            200,
+            text="<ServiceException>not supported</ServiceException>",
+            headers={"content-type": "application/xml"},
+        )
+    )
+
+    client = GIBSClient()
+    await client.initialize()
+
+    result = await client.get_legend_image("AMSR2_Sea_Ice_Concentration_12km_Monthly")
+    assert result is None
+
+    await client.close()
+
+
 # ---------------------------------------------------------------------------
 # Client.http property guard
 # ---------------------------------------------------------------------------