diff --git a/psasim/README.md b/psasim/README.md
index 7b7c77361..e8f286318 100644
--- a/psasim/README.md
+++ b/psasim/README.md
@@ -1,11 +1,18 @@
 # psasim
 
-This is a library that simulates a PSA Firmware Framework compliant implementation.
+This tool simulates a PSA Firmware Framework implementation.
 It allows you to develop secure partitions and their clients on a desktop computer.
 It should be able to run on all systems that support POSIX and System V IPC:
-e.g. macOS, Linux, FreeBSD, and perhaps Windows 10 WSL2. 
+e.g. macOS, Linux, FreeBSD, and perhaps Windows 10 WSL2.
 
-To build and run the test program make sure you have `make`, `python` and a 
+Please note that the code in this directory is maintained by the Mbed TLS / PSA Crypto project solely for the purpose of testing the use of Mbed TLS with client/service separation. We do not recommend using this code for any other purpose. In particular:
+
+* This simulator is not intended to pass or demonstrate compliance.
+* This code is only intended for simulation and does not have any security goals. It does not isolate services from clients.
+
+## Building
+
+To build and run the test program make sure you have `make`, `python` and a
 C compiler installed and then enter the following commands:
 
 ```sh
@@ -15,33 +22,26 @@ make run
 
 On Linux you may need to run `ldconfig` to ensure the library is properly installed.
 
-An example pair of programs is included in the **test** directory.
+An example pair of programs is included in the `test` directory.
 
-The implemented API is compliant with PSA-FF 1.0.0 with the exception of 
-a couple of things that are a work in progress:
+## Features
+
+The implemented API is intended to be compliant with PSA-FF 1.0.0 with the exception of a couple of things that are a work in progress:
 
 * `psa_notify` support
 * "strict" policy in manifest
 
 The only supported "interrupts" are POSIX signals, which act
-as a "virtual interrupt" :-)
+as a "virtual interrupt".
 
-The standard PSA RoT APIs are not included (e.g. cryptography, attestation, lifecycle etc). 
+The standard PSA RoT APIs are not included (e.g. cryptography, attestation, lifecycle etc).
 
 ## Design
 
-The code is designed to be readable rather than fast.
-In this implementation only one message is delivered to a 
+The code is designed to be readable rather than fast or secure.
+In this implementation only one message is delivered to a
 RoT service at a time.
-Things that need to be done to improve this implementation:
-
-* run against the official test suite
-* make thread safe
-* make code more readable
-* improve quality of code
-* man pages
-* use sockets for message passing (WSL doesn't support System V message queues)
-* general robustness and hardening
+The code is not thread-safe.
 
 To debug the simulator enable the debug flag:
 
@@ -55,6 +55,6 @@ Because this is a simulator there are a few things that
 can't be reasonably emulated:
 
 * Manifest MMIO regions are unsupported
-* Manifest priority field is ignored 
-* Partition IDs are in fact POSIX `pid_t`, which are only assigned at runtime, 
-  making it infeasible to populate pid.h with correct values. 
+* Manifest priority field is ignored
+* Partition IDs are in fact POSIX `pid_t`, which are only assigned at runtime,
+  making it infeasible to populate pid.h with correct values.