fix(cli): preserve output and comparison input validation (#981)

src/cliOutput.ts

@@ -6,6 +6,7 @@ const UNSUPPORTED_OUTPUT_COMBINATION_MESSAGE =
   "Token windows cannot preserve structured output. Remove --token-limit/--token-offset and use --filter-output or command pagination.";
 
 type StructuredOutputFormat = "json" | "jsonl" | "yaml";
+const INCUR_OUTPUT_FORMATS = new Set(["toon", "json", "yaml", "md", "jsonl"]);
 
 export type CliOutputArgumentValidation =
   | { readonly ok: true }
@@ -21,6 +22,7 @@ type JsonRecord = Record<string, unknown>;
 interface ParsedCliOutputArguments {
   readonly filterOutput: boolean;
   readonly format: string;
+  readonly parseError: boolean;
   readonly tokenWindow: boolean;
 }
 
@@ -50,40 +52,45 @@ const parseCliOutputArguments = (
     }
     if (argument === "--format") {
       const value = arguments_[index + 1];
-      if (value !== undefined) {
+      if (value) {
+        // Incur stops parsing at an invalid format before applying any later
+        // output controls. Let it report that malformed flag itself.
+        if (!INCUR_OUTPUT_FORMATS.has(value))
+          return { filterOutput, format, parseError: true, tokenWindow: false };
         format = value;
         index += 1;
       }
       continue;
     }
     if (argument === "--filter-output") {
-      if (arguments_[index + 1] !== undefined) {
+      if (arguments_[index + 1]) {
         filterOutput = true;
         index += 1;
       }
       continue;
     }
     if (argument === "--token-limit" || argument === "--token-offset") {
-      if (arguments_[index + 1] !== undefined) {
+      const value = arguments_[index + 1];
+      if (value) {
+        const numericValue = Number(value);
+        if (!Number.isFinite(numericValue) || value.trim() === "")
+          return { filterOutput, format, parseError: true, tokenWindow: false };
         tokenWindow = true;
         index += 1;
       }
       continue;
     }
-    if (
-      argument?.startsWith("--token-limit=") ||
-      argument?.startsWith("--token-offset=")
-    )
-      tokenWindow = true;
   }
-  return { filterOutput, format, tokenWindow };
+  return { filterOutput, format, parseError: false, tokenWindow };
 };
 
 /** Reject text-window controls that would corrupt a structured document. */
 export const validateCliOutputArguments = (
   arguments_: readonly string[],
 ): CliOutputArgumentValidation => {
-  const { format, tokenWindow } = parseCliOutputArguments(arguments_);
+  const { format, parseError, tokenWindow } =
+    parseCliOutputArguments(arguments_);
+  if (parseError) return { ok: true };
   if (
     tokenWindow &&
     (format === "json" || format === "jsonl" || format === "yaml")
@@ -101,7 +108,9 @@ export const validateCliOutputArguments = (
 export const renderEmptyFilteredCliOutput = (
   arguments_: readonly string[],
 ): string | undefined => {
-  const { filterOutput, format } = parseCliOutputArguments(arguments_);
+  const { filterOutput, format, parseError } =
+    parseCliOutputArguments(arguments_);
+  if (parseError) return undefined;
   if (
     filterOutput &&
     (format === "json" || format === "jsonl" || format === "yaml")