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diff --git a/src/FundLab.Api/StockDailyProbe.fs b/src/FundLab.Api/StockDailyProbe.fs
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+namespace FundLab.Api
+
+open System
+open System.Collections.Concurrent
+open System.Threading
+
+/// One daily close of a stock's history.
+type StockDailyObservation =
+    {
+        BarDate: DateOnly
+        Close: decimal
+        Volume: decimal option
+        Amount: decimal option
+    }
+
+/// Read-only probe that returns recent daily history for a stock code.
+///
+/// Like the other market probes there is no synthetic fallback: a failure is
+/// surfaced as a MarketDataFailure so the API answers 503 with the reason.
+type IStockDailyProbe =
+    abstract RecentDaily: code: string * days: int * CancellationToken -> Result<StockDailyObservation list, MarketDataFailure>
+
+/// AKShare-backed stock-daily probe. Successful lookups are memoised per code
+/// and requested window; failures are never cached. A payload whose instrument
+/// code disagrees with the request is rejected outright.
+type AkshareStockDailyProbe(collector: IMarketDataCollector) =
+    let cache = ConcurrentDictionary<string, StockDailyObservation list>(StringComparer.Ordinal)
+
+    let isStockCode (value: string) =
+        not (String.IsNullOrWhiteSpace value)
+        && value.Length = 6
+        && value |> Seq.forall Char.IsDigit
+
+    let clip days =
+        if days < 1 then 1
+        elif days > 30 then 30
+        else days
+
+    member _.Clear() = cache.Clear()
+
+    interface IStockDailyProbe with
+        member _.RecentDaily(code, days, token) =
+            let normalized = if isNull code then "" else code.Trim()
+
+            if not (isStockCode normalized) then
+                Error(InvalidMarketDataRequest "stock code must contain exactly six digits")
+            else
+                let bounded = clip days
+                let cacheKey = sprintf "%s|%d" normalized bounded
+
+                match cache.TryGetValue cacheKey with
+                | true, cached -> Ok cached
+                | _ ->
+                    match collector.FetchStockDaily(normalized, bounded, token) with
+                    | Error message -> Error(MarketDataCollectorUnavailable message)
+                    | Ok json ->
+                        match MarketData.parseStockDailyPayload json with
+                        | Error message -> Error(InvalidMarketDataPayload message)
+                        | Ok payload when not (String.Equals(payload.Code, normalized, StringComparison.Ordinal)) ->
+                            Error(
+                                InvalidMarketDataPayload(
+                                    sprintf "payload code '%s' does not match requested code '%s'" payload.Code normalized
+                                )
+                            )
+                        | Ok payload ->
+                            let observations =
+                                payload.Bars
+                                |> List.filter (fun bar -> bar.Close > 0m)
+                                |> List.map (fun bar ->
+                                    {
+                                        BarDate = bar.BarDate
+                                        Close = bar.Close
+                                        Volume = bar.Volume
+                                        Amount = bar.Amount
+                                    })
+                                |> List.distinctBy (fun bar -> bar.BarDate)
+                                |> List.sortBy (fun bar -> bar.BarDate)
+
+                            cache.[cacheKey] <- observations
+                            Ok observations