fix(cli): read piped stdin to EOF instead of the first line (#166)

scripts/test_completion.sh

@@ -22,4 +22,20 @@ total="$(printf '%s\n' "$line" | sed 's|COMPTEST ||' | cut -d/ -f2)"
 if printf '%s\n' "$out" | grep -q 'FAIL' || [ "$passed" != "$total" ]; then
     echo "RESULT: FAIL ($line)"; exit 1
 fi
+# ── #166: piped stdin must be read to EOF, not truncated to the first line ──────────
+# QWISP_FAKE=1 uses FakeBackend: no model weights, no GPU — only the tokenizer this gate
+# already requires. Asserts a strict increase rather than an exact count so it does not
+# encode the tokenizer's segmentation. Before the fix both arms reported 11 tok.
+tok_of() {
+    printf '%b' "$1" | QWISP_FAKE=1 QWISP_MODEL="$MODEL" "$BIN" chat --max-tokens 2 2>&1 \
+        | sed -n 's/.*prompt \([0-9]*\) tok.*/\1/p'
+}
+one="$(tok_of 'alpha\n')"
+two="$(tok_of 'alpha\nbeta gamma delta epsilon zeta eta theta iota kappa lambda\n')"
+if [ -z "$one" ] || [ -z "$two" ] || [ "$two" -le "$one" ]; then
+    echo "RESULT: FAIL (piped stdin truncated to line 1: 1-line=${one:-NA} tok, 2-line=${two:-NA} tok — #166)"
+    exit 1
+fi
+echo "[stdin] piped multi-line read to EOF: 1-line=$one tok < 2-line=$two tok  ok"
+
 echo "RESULT: PASS ($line)"

swift/Sources/qwisp/main.swift

@@ -123,7 +123,21 @@ case "chat":
         }
     }
     let promptText = rest.joined(separator: " ")
-    let prompt = promptText.isEmpty ? (readLine(strippingNewline: true) ?? "") : promptText
+    // Piped stdin is a documented input path ("or pipe text via stdin" in the usage line), and
+    // readLine() takes only the FIRST line — `cat spec.md | qwisp chat` silently answered on
+    // line 1 and exited 0 (#166; it ingested 52 tokens of a 35K-token file while reporting a
+    // healthy run). Read to EOF when stdin is not a TTY; keep readLine() interactively, where
+    // one line IS what the user means and reading to EOF would block until ^D.
+    let prompt: String
+    if !promptText.isEmpty {
+        prompt = promptText
+    } else if isatty(FileHandle.standardInput.fileDescriptor) == 1 {
+        prompt = readLine(strippingNewline: true) ?? ""
+    } else {
+        let piped = FileHandle.standardInput.readDataToEndOfFile()
+        prompt = String(decoding: piped, as: UTF8.self)
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+    }
     if prompt.isEmpty {
         print("usage: qwisp chat [--max-tokens N] [--lossless] <prompt>   (or pipe text via stdin)")
     } else {