fix: widen Rich console and traceback output

Add rich_console_width setting (default 120) to control Rich console
width for better readability of tracebacks and console output.

This fixes the issue where Rich tracebacks were extremely narrow
and hard to read by setting a reasonable default width.

Co-authored-by: William Easton <strawgate@users.noreply.github.com>

src/fastmcp/__init__.py

@@ -10,6 +10,7 @@ if settings.log_enabled:
     _configure_logging(
         level=settings.log_level,
         enable_rich_tracebacks=settings.enable_rich_tracebacks,
+        console_width=settings.rich_console_width,
     )
 
 from fastmcp.server.server import FastMCP

src/fastmcp/settings.py

@@ -172,6 +172,19 @@ class Settings(BaseSettings):
         ),
     ] = True
 
+    rich_console_width: Annotated[
+        int | None,
+        Field(
+            description=inspect.cleandoc(
+                """
+                Width for Rich console output including tracebacks. If None, 
+                Rich will auto-detect the terminal width. Set to a larger value
+                (e.g., 120, 140) for wider tracebacks that show more code context.
+                """
+            )
+        ),
+    ] = 120
+
     deprecation_warnings: Annotated[
         bool,
         Field(

src/fastmcp/utilities/cli.py

@@ -231,5 +231,8 @@ def log_server_banner(
         expand=False,
     )
 
-    console = Console(stderr=True)
+    from fastmcp.settings import Settings
+
+    settings = Settings()
+    console = Console(stderr=True, width=settings.rich_console_width)
     console.print(Group("\n", panel, "\n"))

src/fastmcp/utilities/logging.py

@@ -23,6 +23,7 @@ def configure_logging(
     level: Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"] | int = "INFO",
     logger: logging.Logger | None = None,
     enable_rich_tracebacks: bool = True,
+    console_width: int | None = None,
     **rich_kwargs: Any,
 ) -> None:
     """
@@ -31,6 +32,7 @@ def configure_logging(
     Args:
         logger: the logger to configure
         level: the log level to use
+        console_width: width for Rich console output
         rich_kwargs: the parameters to use for creating RichHandler
     """
 
@@ -39,7 +41,7 @@ def configure_logging(
 
     # Only configure the FastMCP logger namespace
     handler = RichHandler(
-        console=Console(stderr=True),
+        console=Console(stderr=True, width=console_width),
         rich_tracebacks=enable_rich_tracebacks,
         **rich_kwargs,
     )