fix(server): /answer takes a question id and refuses a stale reply

src/Cli/WorkflowMode.php

@@ -306,6 +306,7 @@ private function tailRun(ServerClient $client, array $server, string $key, strin
         $interactive = stream_isatty(STDIN);
         $since = 0;
         $openPrompt = null;
+        $openQuestion = 0;
         $hinted = false;
 
         while (true) {
@@ -316,6 +317,7 @@ private function tailRun(ServerClient $client, array $server, string $key, strin
 
                 if ($type === 'question') {
                     $openPrompt = (string) ($data['prompt'] ?? 'the run is waiting for a human');
+                    $openQuestion = \is_int($row['spanId'] ?? null) ? $row['spanId'] : 0;
                     $hinted = false;
                 } elseif ($type === 'answer') {
                     $openPrompt = null;
@@ -348,7 +350,7 @@ private function tailRun(ServerClient $client, array $server, string $key, strin
             // it can be answered and keep following, so a piped `claw run` never blocks on input.
             if ($openPrompt !== null) {
                 if ($interactive) {
-                    if ($this->answerGate($client, $server, $key, $issueId, $openPrompt)) {
+                    if ($this->answerGate($client, $server, $key, $issueId, $openPrompt, $openQuestion)) {
                         $openPrompt = null;
                     } else {
                         // input closed — stop asking; suppress the hint this round so it is not doubled
@@ -376,7 +378,7 @@ private function tailRun(ServerClient $client, array $server, string $key, strin
      *
      * @param array{host: string, port: int} $server
      */
-    private function answerGate(ServerClient $client, array $server, string $key, string $issueId, string $prompt): bool
+    private function answerGate(ServerClient $client, array $server, string $key, string $issueId, string $prompt, int $questionId): bool
     {
         fwrite(STDOUT, "\n⏸ {$prompt}\n");
 
@@ -400,7 +402,7 @@ private function answerGate(ServerClient $client, array $server, string $key, st
             }
 
             try {
-                $client->answer($server, $key, $issueId, $text);
+                $client->answer($server, $key, $issueId, $text, $questionId);
             } catch (ClawException $e) {
                 fwrite(STDERR, '  ' . $e->getMessage() . "\n");
             }

src/Server.php

@@ -223,6 +223,20 @@ private function adoptOrphanedRuns(): void
      * the resumed run reads the journal on its way into the gate, so the answer has to be there before
      * it looks. Reversed, it would ask again and the reply would land on a question nobody is at.
      */
+    /** The id of the question an issue's run is currently waiting on, or null when none is open. */
+    private function openQuestionId(ProjectStoreInterface $store, string $issueId): ?int
+    {
+        $reader = new TraceReader($store->pdo());
+
+        foreach ($store->runningRuns() as $run) {
+            if ($run['issue'] === $issueId && ($gate = $reader->openGate($run['id'])) !== null) {
+                return (int) $gate['id'];
+            }
+        }
+
+        return null;
+    }
+
     private function deliverToADeadGate(
         HttpResponse $response,
         ProjectStoreInterface $store,
@@ -1252,6 +1266,20 @@ private function answer(HttpRequest $request, HttpResponse $response, string $ke
 
         $payload = \json_decode($request->getBody(), true);
         $text = \is_array($payload) && isset($payload['text']) ? (string) $payload['text'] : '';
+
+        // When the caller names the question it is answering, refuse a reply meant for one that has
+        // already moved on — a terminal user typing while the same gate was answered in the dashboard
+        // and the run opened a new question. The id lives in the trace the caller is reading. Callers
+        // that send no id (older ones) keep the previous behaviour.
+        $question = \is_array($payload) && isset($payload['question']) ? (int) $payload['question'] : 0;
+        $open = $question > 0 ? $this->openQuestionId($store, $issueId) : null;
+
+        if ($open !== null && $open !== $question) {
+            $response->json(['error' => 'that question has been answered — a newer one is waiting'], 409);
+
+            return;
+        }
+
         $channel = $this->gates[$key . '/' . $issueId] ?? null;
 
         if ($channel !== null) {

src/ServerClient.php

@@ -6,6 +6,7 @@
 
 use Claw\Exceptions\ClawException;
 use Claw\Http\HttpClientInterface;
+use Claw\Http\HttpResponse;
 
 /**
  * The CLI's side of the one-writer rule: it does not open a project db, it asks the server to. The
@@ -96,11 +97,16 @@ public function startRun(array $server, string $key, string $issueId): void
     /**
      * Send a person's reply to a run's open gate.
      *
+     * $questionId names the question being answered (0 to omit). The server refuses a reply aimed at a
+     * question that has since been answered and replaced — the id is what closes the terminal-vs-dashboard
+     * race the blocking prompt opens.
+     *
      * @param array{host: string, port: int} $server
      *
-     * @throws ClawException when the run is not waiting (409) or the server refuses the answer
+     * @throws ClawException when the run is not waiting, the question has moved on (409), or the server
+     *                       refuses the answer
      */
-    public function answer(array $server, string $key, string $issueId, string $text): void
+    public function answer(array $server, string $key, string $issueId, string $text, int $questionId = 0): void
     {
         $url = sprintf(
             'http://%s:%d/api/projects/%s/issues/%s/answer',
@@ -110,7 +116,13 @@ public function answer(array $server, string $key, string $issueId, string $text
             rawurlencode($issueId),
         );
 
-        $body = json_encode(['text' => $text]);
+        $fields = ['text' => $text];
+
+        if ($questionId > 0) {
+            $fields['question'] = $questionId;
+        }
+
+        $body = json_encode($fields);
 
         if ($body === false) {
             throw new ClawException('cannot send the answer: it is not valid text');
@@ -123,12 +135,20 @@ public function answer(array $server, string $key, string $issueId, string $text
         }
 
         if ($response->status === 409) {
-            throw new ClawException('the run is not waiting for an answer right now');
+            throw new ClawException($this->errorText($response) ?? 'the run is not waiting for an answer right now');
         }
 
         throw new ClawException("the server refused the answer (HTTP {$response->status})");
     }
 
+    /** The server's own `error` message from a JSON body, or null when there is not one to show. */
+    private function errorText(HttpResponse $response): ?string
+    {
+        $data = json_decode($response->body, true);
+
+        return \is_array($data) && \is_string($data['error'] ?? null) ? $data['error'] : null;
+    }
+
     /**
      * The runs recorded for an issue, oldest first — how the CLI finds the run a start produced, since
      * the id is minted inside the run and not returned by the start.

tests/ServerClientTest.php

@@ -170,16 +170,36 @@ public function anAnswerAcceptedReturnsQuietlyAndCarriesTheText(): void
     }
 
     #[Test]
-    public function answeringAGateThatIsNotWaitingIsReported(): void
+    public function anAnswerNamesTheQuestionItIsFor(): void
+    {
+        $http = new FakeHttpClient(new HttpResponse(202, ''));
+        new ServerClient($http, $this->workspace, '/opt/claw')
+            ->answer(['host' => '127.0.0.1', 'port' => 8787], 'proj', '7', 'merge sort', 42);
+
+        Assert::same(str_contains((string) $http->lastBody, '"question":42'), true);
+    }
+
+    #[Test]
+    public function withoutAQuestionIdNoneIsSent(): void
+    {
+        $http = new FakeHttpClient(new HttpResponse(202, ''));
+        new ServerClient($http, $this->workspace, '/opt/claw')
+            ->answer(['host' => '127.0.0.1', 'port' => 8787], 'proj', '7', 'hi');
+
+        Assert::same(str_contains((string) $http->lastBody, 'question'), false);
+    }
+
+    #[Test]
+    public function aRejectedAnswerSurfacesTheServersOwnReason(): void
     {
         $threw = false;
 
         try {
-            $this->client(new HttpResponse(409, '{"error":"the run is not waiting for an answer right now"}'))
-                ->answer(['host' => '127.0.0.1', 'port' => 8787], 'proj', '7', 'hi');
+            $this->client(new HttpResponse(409, '{"error":"that question has been answered — a newer one is waiting"}'))
+                ->answer(['host' => '127.0.0.1', 'port' => 8787], 'proj', '7', 'hi', 42);
         } catch (ClawException $e) {
             $threw = true;
-            Assert::same(str_contains($e->getMessage(), 'not waiting'), true);
+            Assert::same(str_contains($e->getMessage(), 'a newer one is waiting'), true);
         }
 
         Assert::same($threw, true);