diff --git a/prospect/drivers/tcp.rkt b/prospect/drivers/tcp.rkt
index fdc109c..4dcfda5 100644
--- a/prospect/drivers/tcp.rkt
+++ b/prospect/drivers/tcp.rkt
@@ -3,7 +3,7 @@
 (require racket/match)
 (require (prefix-in tcp: racket/tcp))
 (require (only-in racket/port read-bytes-avail!-evt))
-(require (only-in web-server/private/util exn->string))
+(require "../exn-util.rkt")
 (require "../main.rkt")
 (require "../demand-matcher.rkt")
 
diff --git a/prospect/exn-util.rkt b/prospect/exn-util.rkt
new file mode 100644
index 0000000..17e23ed
--- /dev/null
+++ b/prospect/exn-util.rkt
@@ -0,0 +1,8 @@
+#lang racket/base
+
+(provide exn->string)
+
+(define (exn->string exn)
+  (parameterize ([current-error-port (open-output-string)])
+    ((error-display-handler) (exn-message exn) exn)
+    (get-output-string (current-error-port))))
diff --git a/prospect/pretty.rkt b/prospect/pretty.rkt
index 2e6465c..0bc9a0b 100644
--- a/prospect/pretty.rkt
+++ b/prospect/pretty.rkt
@@ -3,14 +3,14 @@
 (provide gen:prospect-pretty-printable
          prospect-pretty-print
 
-         exn->string ;; required from web-server/private/util
+         exn->string ;; required from exn-util.rkt
          string-indent
          indented-port-output)
 
 (require racket/generic)
 (require racket/pretty)
-(require (only-in web-server/private/util exn->string))
 (require (only-in racket/string string-join string-split))
+(require "exn-util.rkt")
 
 (define-generics prospect-pretty-printable
   (prospect-pretty-print prospect-pretty-printable [port])
diff --git a/prospect/trace/stderr.rkt b/prospect/trace/stderr.rkt
index 8104727..1b9e256 100644
--- a/prospect/trace/stderr.rkt
+++ b/prospect/trace/stderr.rkt
@@ -6,7 +6,7 @@
 (require racket/match)
 (require racket/pretty)
 (require (only-in racket/string string-join))
-(require (only-in web-server/private/util exn->string))
+(require "../exn-util.rkt")
 (require "../core.rkt")
 (require "../trace.rkt")
 (require "../mux.rkt")