build: a bare {chain} in a mail body goes, on its own line or inline

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/build.rs

@@ -1045,14 +1045,23 @@ fn keep_links(fallback: &Value, merged: &mut Value) {
     for (bucket, stages) in fb {
         let Some(ms) = mb.get_mut(bucket).and_then(Value::as_object_mut) else { continue };
         for (stage, spec) in stages.as_object().into_iter().flatten() {
-            let Some(link) = spec["body"].as_str().and_then(|b| b.lines().find(|l| l.contains("{site}/decide/"))) else { continue };
+            let link = spec["body"].as_str().and_then(|b| b.lines().find(|l| l.contains("{site}/decide/")));
             let Some(body) = ms.get_mut(stage).and_then(|m| m.get_mut("body")) else { continue };
             let Some(text) = body.as_str() else { continue };
-            if text.contains("/decide/") {
-                continue;
+            // A bare `{chain}` outside a link is the record id pasted
+            // into prose, which a model does when told to keep
+            // placeholders; it goes, on its own line or inline.
+            let cleaned: Vec<String> = text
+                .lines()
+                .map(|l| if l.contains("/decide/") { l.to_string() } else { l.replace("{chain}", "").split_whitespace().collect::<Vec<_>>().join(" ") })
+                .collect();
+            let mut cleaned = cleaned.join("\n").trim_end().to_string();
+            if let Some(link) = link {
+                if !cleaned.contains("/decide/") {
+                    cleaned = format!("{cleaned}\n\n{link}");
+                }
             }
-            let kept: Vec<&str> = text.lines().filter(|l| l.trim() != "{chain}").collect();
-            *body = Value::String(format!("{}\n\n{link}", kept.join("\n").trim_end()));
+            *body = Value::String(cleaned);
         }
     }
 }
@@ -1723,11 +1732,12 @@ mod tests {
     #[test]
     fn a_models_mail_keeps_the_submitters_link() {
         let fallback = json!({ "leaks": { "open": { "subject": "s", "body": "Hello,\n\nGot it.\n\nWhat you can do next: {site}/decide/leak?chain={chain}&email={email}\n\nI at i@b.example" } } });
-        let mut merged = json!({ "leaks": { "open": { "subject": "Got it", "body": "Hi,\n\nWe have it.\n\n{chain}" } } });
+        let mut merged = json!({ "leaks": { "open": { "subject": "Got it", "body": "Hi,\n\nWe have it. {chain}\n\n{chain}" } } });
         keep_links(&fallback, &mut merged);
         let body = merged["leaks"]["open"]["body"].as_str().unwrap();
         assert!(body.ends_with("What you can do next: {site}/decide/leak?chain={chain}&email={email}"));
-        assert!(!body.contains("\n{chain}"));
+        assert!(!body.contains("it. {chain}") && !body.contains("\n{chain}"));
+        assert!(body.starts_with("Hi,\n\nWe have it."));
         // A body that kept its link is left alone.
         let mut fine = json!({ "leaks": { "open": { "subject": "s", "body": "Withdraw here: {site}/decide/leak?chain={chain}&email={email}" } } });
         keep_links(&fallback, &mut fine);