diff --git a/README.md b/README.md
index 436926bf..7d722888 100644
--- a/README.md
+++ b/README.md
@@ -95,6 +95,32 @@ gh webhook forward --repo=ehuss/triagebot-test --events=* \
 
 Where the value in `--secret` is the secret value you place in `GITHUB_WEBHOOK_SECRET` in the `.env` file, and `--repo` is the repo you want to test against.
 
+You can test webhooks with `cURL`. For example to test the Zulip hooks (commands sent to the
+Triagebot from the Rust lang Zulip), you start the triagebot on localhost:8000 and then simulate a
+Zulip hook payload:
+``` sh
+curl http://localhost:8000/zulip-hook \
+    -H "Content-Type: application/json" \
+    -d '{
+        "data": "<CMD>",
+        "token": "<ZULIP_TOKEN>",
+        "message": {
+            "sender_id": <YOUR_ID>,
+            "recipient_id": <YOUR_ID>,
+            "sender_full_name": "Randolph Carter",
+            "sender_email": "r.carter@rust-lang.org",
+            "type": "stream"
+            }
+        }'
+```
+
+Where:
+- `CMD` is the exact command you would issue @triagebot on Zulip (ex. open a direct chat with the
+  bot and send "work show")
+- `ZULIP_TOKEN`: can be anything. Must correspond to the env var `$ZULIP_TOKEN` on your workstation
+- `YOUR_ID`: your GitHub user ID. Must be existing in your local triagebot database (table `users` and as
+  foreign key also in `review_prefs`)
+
 #### ngrok
 
 The following is an example of using <https://ngrok.com/> to provide webhook forwarding.
diff --git a/src/db.rs b/src/db.rs
index c74606cf..ff3add0d 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -344,4 +344,5 @@ CREATE EXTENSION IF NOT EXISTS intarray;",
     "
 CREATE UNIQUE INDEX IF NOT EXISTS review_prefs_user_id ON review_prefs(user_id);
  ",
+    "ALTER TABLE review_prefs ADD COLUMN max_assigned_prs INT DEFAULT NULL;",
 ];
diff --git a/src/handlers/pull_requests_assignment_update.rs b/src/handlers/pull_requests_assignment_update.rs
index 95edde32..7e7d3baa 100644
--- a/src/handlers/pull_requests_assignment_update.rs
+++ b/src/handlers/pull_requests_assignment_update.rs
@@ -88,18 +88,16 @@ WHERE r.user_id = $1;";
 pub async fn set_review_prefs(
     db: &DbClient,
     user_id: u64,
-    max: u32,
-) -> anyhow::Result<ReviewPrefs> {
+    pref_max_prs: u32,
+) -> anyhow::Result<u64, anyhow::Error> {
     let q = "
 UPDATE review_prefs r
-SET max_assigned_prs = $2
+SET max_assigned_prs = $1
 FROM users u
-WHERE r.user_id=$1 AND u.user_id=r.user_id
-RETURNING u.username, r.*";
-    let row = db
-        .query_one(q, &[&(max as i32), &(user_id as i64)])
+WHERE r.user_id=$2 AND u.user_id=r.user_id;";
+    let res = db
+        .execute(q, &[&(pref_max_prs as i32), &(user_id as i64)])
         .await
-        .context("Error retrieving review preferences")
-        .unwrap();
-    Ok(row.into())
+        .context("Error setting review preferences")?;
+    Ok(res)
 }
diff --git a/src/lib.rs b/src/lib.rs
index 9a8e8569..bc663ba1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -131,17 +131,27 @@ pub struct ReviewPrefs {
     pub username: String,
     pub user_id: i64,
     pub assigned_prs: Vec<i32>,
+    pub max_assigned_prs: Option<u32>,
 }
 
-impl ReviewPrefs {
-    fn to_string(&self) -> String {
+impl fmt::Display for ReviewPrefs {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let prs = self
             .assigned_prs
             .iter()
             .map(|pr| format!("#{}", pr))
             .collect::<Vec<String>>()
             .join(", ");
-        format!("Username: {}\nAssigned PRs: {}", self.username, prs)
+        let max = if self.max_assigned_prs.is_none() {
+            "<not set>"
+        } else {
+            &format!("{}", self.max_assigned_prs.expect("NaN"))
+        };
+        write!(
+            f,
+            "Username: {}\nAssigned PRs: {}\nCurrent review capacity: {}",
+            self.username, prs, max
+        )
     }
 }
 
@@ -152,6 +162,7 @@ impl From<tokio_postgres::row::Row> for ReviewPrefs {
             username: row.get("username"),
             user_id: row.get("user_id"),
             assigned_prs: row.get("assigned_prs"),
+            max_assigned_prs: row.get("max_assigned_prs"),
         }
     }
 }
diff --git a/src/zulip.rs b/src/zulip.rs
index 21da889a..8e041eb1 100644
--- a/src/zulip.rs
+++ b/src/zulip.rs
@@ -264,34 +264,33 @@ async fn query_pr_assignments(
 
     let db_client = ctx.db.get().await;
 
-    let record = match subcommand {
+    let reply = match subcommand {
         "show" => {
-            let rec = get_review_prefs(&db_client, gh_id).await;
-            if rec.is_err() {
-                anyhow::bail!("No preferences set.")
-            }
-            rec?
+            let rec = get_review_prefs(&db_client, gh_id)
+                .await
+                .context("Could not query review preferences")?;
+            rec.to_string()
         }
         "set" => {
-            let max = match words.next() {
+            let pref_max_prs = match words.next() {
                 Some(max_value) => {
                     if words.next().is_some() {
                         anyhow::bail!("Too many parameters.");
                     }
-                    max_value
-                        .parse::<u32>()
-                        .context("Wrong parameter format. Must be a positive integer.")?
+                    max_value.parse::<u32>().context(
+                        "Wrong parameter format. Must be a positive integer (and fit a u32).",
+                    )?
                 }
                 None => anyhow::bail!("Missing parameter."),
             };
-            set_review_prefs(&db_client, gh_id, max)
+            set_review_prefs(&db_client, gh_id, pref_max_prs)
                 .await
-                .context("Error occurred while setting review preferences.")?
+                .context("Could not set review preferences")?;
+            format!("Review capacity set to {}", pref_max_prs)
         }
         _ => anyhow::bail!("Invalid subcommand."),
     };
-
-    Ok(Some(record.to_string()))
+    Ok(Some(reply))
 }
 
 // This does two things: