diff --git a/crates/neuromesh-context/src/activator_seed.rs b/crates/neuromesh-context/src/activator_seed.rs
index 19e14aa..a170b8b 100644
--- a/crates/neuromesh-context/src/activator_seed.rs
+++ b/crates/neuromesh-context/src/activator_seed.rs
@@ -1026,6 +1026,15 @@ fn push_ranked_file_seeds(
             .map(|r| r.score)
             .unwrap_or(0.0)
     };
+    // A plain-language question (no file path, no identifier but prose
+    // words) has one piece of evidence: the whole-question ranking. A word
+    // that matched a symbol elsewhere is a guess the ranking already
+    // weighed, so every guess outside the picks gives way.
+    let plain = {
+        let anchors = neuromesh_parser::extract_prompt_anchors(prompt);
+        anchors.file_hints.is_empty()
+            && anchors.identifiers.iter().all(|i| is_prose_word(prompt, i))
+    };
     let weaker: Vec<NodeId> = sink
         .resolutions()
         .iter()
@@ -1034,7 +1043,7 @@ fn push_ranked_file_seeds(
         .filter(|id| {
             graph.get_node(id).is_some_and(|n| {
                 !picks.iter().any(|p| p.path == n.file_path)
-                    && score_of(&n.file_path) < top * GUESS_FLOOR
+                    && (plain || score_of(&n.file_path) < top * GUESS_FLOOR)
             })
         })
         .collect();
diff --git a/crates/neuromesh-context/src/skeleton.rs b/crates/neuromesh-context/src/skeleton.rs
index f92bb9a..cdf5ec2 100644
--- a/crates/neuromesh-context/src/skeleton.rs
+++ b/crates/neuromesh-context/src/skeleton.rs
@@ -182,6 +182,9 @@ const DOC_FOLD_MIN_LINES: usize = 3;
 /// The signature may run over several lines; the docstring is the first
 /// non-blank line after the line that ends the signature (`:` for Python).
 fn docstring_block(lines: &[&str], start: usize, end: usize) -> Option<(usize, usize)> {
+    // A span can end past the file (a stale or rounded line range): clamp,
+    // never index past the last line.
+    let end = end.min(lines.len().checked_sub(1)?);
     let mut i = start;
     // skip the signature: through the first line ending with `:`
     while i <= end && !lines[i].trim_end().ends_with(':') {
@@ -766,6 +769,11 @@ impl CodeSkeletonizer {
             }
             for (span, is_exon, score) in items {
                 let start = span.start_line.saturating_sub(1).min(lines.len());
+                if start >= lines.len() {
+                    // A span past the end of the file (stale line range):
+                    // nothing to show, and indexing it panicked the query.
+                    continue;
+                }
                 let end = span.end_line.min(lines.len()).saturating_sub(1).max(start);
                 if is_exon {
                     // An open body keeps its code; a long docstring inside it
diff --git a/scripts/compare_baselines.py b/scripts/compare_baselines.py
new file mode 100644
index 0000000..5060ca6
--- /dev/null
+++ b/scripts/compare_baselines.py
@@ -0,0 +1,147 @@
+"""Rank files for every gold question with two outside baselines, same gold.
+
+    python scripts/compare_baselines.py <gold_tasks.toml> <checkout> [--aider]
+
+- bm25: plain file-level BM25 over whitespace/identifier words (k1 1.2, b 0.75),
+  English stopwords dropped — what a search box over the repository does.
+- aider: Aider's own RepoMap (PageRank over definition/reference tags,
+  personalised by the identifiers and file names the question mentions — the
+  same inputs aider derives from a chat message). Needs `pip install aider-chat`.
+
+Prints recall@k and precision@k (k = 1, 3, 5) per baseline. Our engine's
+numbers come from the gold harness (`scripts/benchmark-fast.sh`), which ships a
+variable-size packet; compare its recall with recall@3/@5 here.
+"""
+import math
+import os
+import re
+import subprocess
+import sys
+from collections import Counter
+
+STOP = set(
+    "a an and are as at be by can could do does for from has have how i if in into is it its "
+    "of on or that the their then there these this those to was we were what when where which "
+    "while who why will with without would you your".split()
+)
+SOURCE_EXT = {
+    ".rs", ".py", ".js", ".jsx", ".ts", ".tsx", ".go", ".c", ".h", ".cc", ".cpp", ".hpp",
+    ".java", ".kt", ".scala", ".rb", ".php", ".cs", ".swift", ".jl", ".r", ".R", ".vue",
+    ".svelte", ".lua", ".sh", ".toml", ".yaml", ".yml", ".json", ".html", ".css", ".scss",
+}
+
+
+def load_gold(path):
+    text = open(path, encoding="utf-8").read()
+    tasks = []
+    for block in text.split("[[task]]")[1:]:
+        tid = re.search(r'^id\s*=\s*"([^"]+)"', block, re.M).group(1)
+        prompt = re.search(r'^prompt\s*=\s*"((?:[^"\\]|\\.)*)"', block, re.M).group(1)
+        gold = re.findall(r'"([^"]+)"', re.search(r"^gold_files\s*=\s*\[(.*?)\]", block, re.M | re.S).group(1))
+        tasks.append((tid, prompt.replace('\\"', '"'), gold))
+    return tasks
+
+
+def repo_files(root):
+    out = subprocess.run(["git", "-C", root, "ls-files"], capture_output=True, text=True, check=True)
+    return [f for f in out.stdout.splitlines() if os.path.splitext(f)[1] in SOURCE_EXT]
+
+
+def words(text):
+    out = []
+    for raw in re.split(r"[^A-Za-z0-9_]+", text):
+        for part in re.split(r"_|(?<=[a-z0-9])(?=[A-Z])", raw):
+            p = part.lower()
+            if len(p) >= 2 and p.isalpha() and p not in STOP:
+                out.append(p)
+    return out
+
+
+class Bm25:
+    def __init__(self, root, files):
+        self.files = files
+        self.tf = []
+        df = Counter()
+        for f in files:
+            try:
+                text = open(os.path.join(root, f), encoding="utf-8", errors="ignore").read()
+            except OSError:
+                text = ""
+            c = Counter(words(text) + words(f))
+            self.tf.append(c)
+            df.update(c.keys())
+        self.n = len(files)
+        self.avg = sum(sum(c.values()) for c in self.tf) / max(self.n, 1)
+        self.idf = {w: math.log((self.n - d + 0.5) / (d + 0.5) + 1) for w, d in df.items()}
+
+    def rank(self, prompt):
+        q = set(words(prompt))
+        scores = []
+        for f, c in zip(self.files, self.tf):
+            length = sum(c.values()) or 1
+            s = 0.0
+            for w in q:
+                t = c.get(w, 0)
+                if t:
+                    s += self.idf[w] * t * 2.2 / (t + 1.2 * (0.25 + 0.75 * length / self.avg))
+            if s > 0:
+                scores.append((s, f))
+        scores.sort(reverse=True)
+        return [f for _, f in scores]
+
+
+class AiderRank:
+    def __init__(self, root, files):
+        from aider.io import InputOutput
+        from aider.repomap import RepoMap
+
+        class Tokens:
+            def token_count(self, text):
+                return len(text) // 4
+
+        self.root = root
+        self.files = [os.path.join(root, f) for f in files]
+        self.rm = RepoMap(map_tokens=4096, root=root, main_model=Tokens(), io=InputOutput(yes=True, pretty=False))
+
+    def rank(self, prompt):
+        idents = set(re.split(r"\W+", prompt)) - {""}
+        mentioned = {f for f in self.files if os.path.basename(f) in prompt}
+        tags = self.rm.get_ranked_tags([], self.files, mentioned, idents)
+        seen, order = set(), []
+        for tag in tags:
+            rel = tag[0] if isinstance(tag, tuple) else tag.rel_fname
+            rel = rel.replace("\\", "/")
+            if rel not in seen:
+                seen.add(rel)
+                order.append(rel)
+        return order
+
+
+def score(ranked, gold, k):
+    top = [f.replace("\\", "/") for f in ranked[:k]]
+    hits = sum(1 for g in gold if any(t.endswith(g) for t in top))
+    return hits / len(gold), (hits / len(top) if top else 0.0)
+
+
+def main():
+    gold_path, root = sys.argv[1], sys.argv[2]
+    tasks = load_gold(gold_path)
+    files = repo_files(root)
+    rankers = {"bm25": Bm25(root, files)}
+    if "--aider" in sys.argv:
+        rankers["aider-repomap"] = AiderRank(root, files)
+    for name, ranker in rankers.items():
+        tot = {k: [0.0, 0.0] for k in (1, 3, 5)}
+        for _, prompt, gold in tasks:
+            ranked = ranker.rank(prompt)
+            for k in tot:
+                r, p = score(ranked, gold, k)
+                tot[k][0] += r
+                tot[k][1] += p
+        n = len(tasks)
+        cells = "  ".join(f"R@{k} {tot[k][0] / n:.3f} P@{k} {tot[k][1] / n:.3f}" for k in (1, 3, 5))
+        print(f"{name:<14} {n} q  {cells}")
+
+
+if __name__ == "__main__":
+    main()