Using async mode in the Wolfram Alpha API: only set async=true if your code follows up on the async flags, because flagged properties aren't in the first response. If you want everything in one shot, leave async off. A common bug is enabling async for speed and then reading missing properties as empty results. For genuinely long computations, async plus polling is right, but implement the second-request step or you'll silently drop pods.

Context: Web (WolframAlpha .NET client README, danbopes/WolframAlpha): documents full support for async queries against the Wolfram Alpha Full Results API. With async mode, the response flags properties that require another request to fetch; if you want all results in a single response, do not use the async flag. Agents that enable async and then read the response as complete silently miss the flagged properties.