docs/swarm/review-classifier.md

@@ -235,8 +235,7 @@ The model answers each classification in JSON. The answer holds:
 
 - a **verdict**, one of _match_, _no match_ or _not applicable to this PR_
 - a **certainty** from 0 to 100, how sure the model is of that verdict
-- a **reason**; the classifier truncates one over 500 characters to 499 plus
-  `…`, and keeps the verdict and certainty
+- a **reason**, at most 500 characters
 
 An answer:
 

swarm-review-classifier/README.md

@@ -18,9 +18,9 @@ forge and holds no forge credential.
 - One `claude --print` per classification, with no session, no tools
   (`--tools ""`), no MCP server, its own empty directory and
   `ANTHROPIC_API_KEY` in its environment only.
-- An answer is a JSON object with a verdict, a certainty and a reason; the
-  classifier truncates a reason over 500 characters to 499 plus `…`. A failed run, a
-  timeout or an answer that doesn't validate leaves that row without a verdict, and it doesn't count.
+- An answer is a JSON object with a verdict, a certainty and a reason of at
+  most 500 characters. A failed run, a timeout or an answer that doesn't
+  validate leaves that row without a verdict, and it doesn't count.
 - A run with no API key, or with no classification answered, fails as a
   whole: the caller sees an error, never a verdict.
 

swarm-review-classifier/src/answer.rs

@@ -1,15 +1,13 @@
 //! Reading the model's answer to one classification.
 //!
-//! An answer that does not parse, names an unknown verdict or carries a
-//! certainty outside 0..=100 is an error, and the row it belongs to is
-//! excluded rather than guessed at. A reason over the cap is not an error: it
-//! is cut to the cap, so the verdict and certainty survive.
+//! An answer that does not parse, names an unknown verdict, carries a
+//! certainty outside 0..=100 or a reason over the cap is an error, and the
+//! row it belongs to is excluded rather than guessed at.
 
 use serde::Deserialize;
 use swarm_queue_client::review_classifier::Verdict;
 
-/// The longest reason, in characters, an answer carries; a longer one is
-/// truncated to this, ending in `…`.
+/// The longest reason, in characters, an answer may carry.
 pub const REASON_MAX_CHARS: usize = 500;
 
 /// One validated answer.
@@ -58,23 +56,19 @@ pub fn parse(text: &str) -> Result<Answer, String> {
                 raw.certainty
             )
         })?;
+    let length = raw.reason.chars().count();
+    if length > REASON_MAX_CHARS {
+        return Err(format!(
+            "the answer's reason is {length} characters, over the {REASON_MAX_CHARS}-character cap"
+        ));
+    }
     Ok(Answer {
         verdict,
         certainty,
-        reason: cap_reason(raw.reason),
+        reason: raw.reason,
     })
 }
 
-/// `reason` cut to `REASON_MAX_CHARS` characters, the last being `…`, if longer.
-fn cap_reason(reason: String) -> String {
-    if reason.chars().count() <= REASON_MAX_CHARS {
-        return reason;
-    }
-    let mut cut: String = reason.chars().take(REASON_MAX_CHARS - 1).collect();
-    cut.push('…');
-    cut
-}
-
 /// `text` without a surrounding code fence, with or without a language tag.
 fn unfence(text: &str) -> &str {
     let Some(inner) = text.strip_prefix("```").and_then(|t| t.strip_suffix("```")) else {
@@ -125,24 +119,16 @@ mod tests {
     }
 
     #[test]
-    fn an_oversized_reason_is_truncated_and_one_at_the_cap_is_kept() {
+    fn an_oversized_reason_is_an_error_and_one_at_the_cap_is_not() {
         let answer = |n: usize| {
             format!(
                 r#"{{"verdict":"match","certainty":90,"reason":"{}"}}"#,
                 "é".repeat(n)
             )
         };
+        let e = parse(&answer(REASON_MAX_CHARS + 1)).expect_err("over the cap");
+        assert!(e.contains("501 characters"), "{e}");
         // Characters, not bytes: `é` is two bytes.
-        let at_cap = parse(&answer(REASON_MAX_CHARS)).expect("at the cap");
-        assert_eq!(at_cap.reason, "é".repeat(REASON_MAX_CHARS));
-
-        let long = parse(&answer(600)).expect("over the cap still parses");
-        assert_eq!(long.verdict, Verdict::Match);
-        assert_eq!(long.certainty, 90);
-        assert_eq!(long.reason.chars().count(), REASON_MAX_CHARS);
-        assert_eq!(
-            long.reason,
-            format!("{}…", "é".repeat(REASON_MAX_CHARS - 1))
-        );
+        assert!(parse(&answer(REASON_MAX_CHARS)).is_ok());
     }
 }