docs(use-cases): scenarios for two-engine reconciliation (ADR-034)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docs/use-cases/audio_upload.feature

@@ -106,3 +106,53 @@ Feature: Upload an audio recording, get a private Swedish transcript, discuss it
     Given my recording's transcript is longer than the caption default
     When I ask a question about it
     Then the transcript is sent with the upload budget, not the 18,000-character caption default
+
+  # ADR-034, two engines and a local reconciler (off unless TAPIR_RECONCILE_BASE_MODEL is set)
+
+  Scenario: Two engines transcribe the audio and their disagreements are reconciled
+    Given two-engine transcription is enabled
+    When a recording is transcribed
+    Then both engines run on the same audio, the fast one first
+    And a local model chooses between their disagreements
+    And the endpoint names every engine and the model that took part
+
+  Scenario: Trivial disagreements never reach the model
+    When the engines differ only by a compound written as one word or two, or by a filler word
+    Then the base reading is kept without a model call
+
+  Scenario: Differences close together are one decision
+    When two differences are separated by a single shared word
+    Then they are asked about as one dispute
+
+  Scenario: An unsure or changed reading is flagged for me
+    When the model changes a reading or cannot decide
+    Then the page lists the spot with a minute mark, both readings and which was used
+    And an unsure spot keeps the base reading and is marked uncertain
+
+  Scenario: The model cannot be a cloud model
+    When the reconciliation model or base engine is not a koala/ or iguana/ alias
+    Then the service refuses to start
+    And a cloud alias that merely contains a local host name is refused too
+
+  Scenario: One engine failing does not fail the upload
+    When one of the two engines fails
+    Then the other engine's transcript is used
+    And the page says only one engine produced it and why
+    And the cloud fallback is not used
+
+  Scenario: Only when both local engines fail does the cloud fallback run
+    When both local engines fail and a fallback is configured
+    Then the fallback transcribes it and the row records that it did
+
+  Scenario: A model that is down gives an unreconciled transcript, not a failed job
+    When the reconciliation model fails three times in a row
+    Then the base transcript is kept unreconciled with the reason
+    And the page says it could not be reconciled
+
+  Scenario: A cancelled job never reaches the cloud
+    When the job is cancelled during either engine
+    Then neither the second engine nor the cloud fallback is called
+
+  Scenario: A single-engine transcript claims no second opinion
+    When only one engine was configured
+    Then the page does not mention reconciliation