diff --git a/Dayflow/Dayflow/Core/AI/DailyRecapGenerator.swift b/Dayflow/Dayflow/Core/AI/DailyRecapGenerator.swift
index 9652f1bb7..02de6bd33 100644
--- a/Dayflow/Dayflow/Core/AI/DailyRecapGenerator.swift
+++ b/Dayflow/Dayflow/Core/AI/DailyRecapGenerator.swift
@@ -218,29 +218,51 @@ final class DailyRecapGenerator {
     }
   }
 
-  static func makeCardsText(day: String, cards: [TimelineCard]) -> String {
-    let ordered = cards.sorted { lhs, rhs in
-      if lhs.startTimestamp == rhs.startTimestamp {
-        return lhs.endTimestamp < rhs.endTimestamp
+  // Rough ceiling on the activity log's size (~15K tokens). Normal days stay far
+  // below it; it only bites when something floods the day with cards (#285).
+  static let recapCardsTextMaxCharacters = 60_000
+
+  static func makeCardsText(
+    day: String, cards: [TimelineCard], maxCharacters: Int = recapCardsTextMaxCharacters
+  ) -> String {
+    let ordered = cards
+      .filter { $0.title != "Processing failed" }
+      .sorted { lhs, rhs in
+        if lhs.startTimestamp == rhs.startTimestamp {
+          return lhs.endTimestamp < rhs.endTimestamp
+        }
+        return lhs.startTimestamp < rhs.startTimestamp
       }
-      return lhs.startTimestamp < rhs.startTimestamp
-    }
 
     guard !ordered.isEmpty else {
       return "No timeline activities were recorded for \(day)."
     }
 
     var lines: [String] = ["Timeline activities for \(day):", ""]
+    var remaining = maxCharacters - lines.joined(separator: "\n").count
+    var includedCount = 0
+
     for (index, card) in ordered.enumerated() {
       let title = standupLine(from: card) ?? "Untitled activity"
       let start = humanReadableClockTime(card.startTimestamp)
       let end = humanReadableClockTime(card.endTimestamp)
-      lines.append("\(index + 1). \(start) - \(end): \(title)")
+      var entryLines = ["\(index + 1). \(start) - \(end): \(title)"]
 
       let summary = card.summary.trimmingCharacters(in: .whitespacesAndNewlines)
       if !summary.isEmpty, summary != title {
-        lines.append("   \(summary)")
+        entryLines.append("   \(summary)")
       }
+
+      let entryLength = entryLines.reduce(0) { $0 + $1.count + 1 }
+      guard entryLength <= remaining else { break }
+      lines.append(contentsOf: entryLines)
+      remaining -= entryLength
+      includedCount += 1
+    }
+
+    if includedCount < ordered.count {
+      let omitted = ordered.count - includedCount
+      lines.append("... and \(omitted) more activities omitted to stay within the model's context limit.")
     }
 
     return lines.joined(separator: "\n")
diff --git a/Dayflow/DayflowTests/DailyRecapCardsTextTests.swift b/Dayflow/DayflowTests/DailyRecapCardsTextTests.swift
new file mode 100644
index 000000000..813c17f9a
--- /dev/null
+++ b/Dayflow/DayflowTests/DailyRecapCardsTextTests.swift
@@ -0,0 +1,99 @@
+import XCTest
+
+@testable import Dayflow
+
+final class DailyRecapCardsTextTests: XCTestCase {
+  func testExcludesProcessingFailedCardsFromPrompt() {
+    let text = DailyRecapGenerator.makeCardsText(
+      day: "2026-06-16",
+      cards: [card(title: "Processing failed", minute: 0), card(title: "Wrote the report", minute: 30)]
+    )
+
+    XCTAssertFalse(text.contains("Processing failed"))
+    XCTAssertTrue(text.contains("1. 9:30am - 9:31am: Wrote the report"))
+
+    let onlyFailed = DailyRecapGenerator.makeCardsText(
+      day: "2026-06-16", cards: [card(title: "Processing failed", minute: 0)]
+    )
+    XCTAssertEqual(onlyFailed, "No timeline activities were recorded for 2026-06-16.")
+  }
+
+  func testTruncatesDeterministicallyWhenOverCharacterBudget() {
+    let cards = (0..<50).map { card(title: "Activity number \($0)", minute: $0) }
+    let makeText = {
+      DailyRecapGenerator.makeCardsText(day: "2026-06-16", cards: cards, maxCharacters: 400)
+    }
+
+    let text = makeText()
+    let includedCount = text.split(separator: "\n").filter { $0.contains(": Activity") }.count
+    XCTAssertTrue((1..<50).contains(includedCount))
+    XCTAssertTrue(text.contains("1. 9:00am - 9:01am: Activity number 0"))
+    XCTAssertTrue(text.contains("... and \(50 - includedCount) more activities omitted"))
+    XCTAssertLessThan(text.count, 500)
+    XCTAssertEqual(text, makeText())
+  }
+
+  func testEmptyCardListReturnsNoActivitiesMessage() {
+    let text = DailyRecapGenerator.makeCardsText(day: "2026-06-16", cards: [])
+    XCTAssertEqual(text, "No timeline activities were recorded for 2026-06-16.")
+  }
+
+  func testIncludesDistinctSummaryButNotSummaryEqualToTitle() {
+    let withSummary = DailyRecapGenerator.makeCardsText(
+      day: "2026-06-16",
+      cards: [card(title: "Wrote the report", minute: 0, summary: "Drafted Q2 numbers")]
+    )
+    XCTAssertTrue(withSummary.contains("Drafted Q2 numbers"))
+
+    // A summary identical to the title is redundant and must be dropped, not
+    // printed twice.
+    let redundant = DailyRecapGenerator.makeCardsText(
+      day: "2026-06-16",
+      cards: [card(title: "Wrote the report", minute: 0, summary: "Wrote the report")]
+    )
+    let occurrences = redundant.components(separatedBy: "Wrote the report").count - 1
+    XCTAssertEqual(occurrences, 1)
+  }
+
+  // Filtering "Processing failed" and character-budget truncation must compose:
+  // failed cards are removed BEFORE the budget is measured, so they never
+  // consume budget or count toward the "omitted" tally.
+  func testFilterAndTruncationCompose() {
+    var cards: [TimelineCard] = []
+    for i in 0..<20 {
+      cards.append(card(title: "Processing failed", minute: i))
+      cards.append(card(title: "Real activity \(i)", minute: i))
+    }
+    let text = DailyRecapGenerator.makeCardsText(
+      day: "2026-06-16", cards: cards, maxCharacters: 300
+    )
+    XCTAssertFalse(text.contains("Processing failed"))
+    if text.contains("omitted") {
+      // The omitted count must reference only the 20 real cards, never the 40 total.
+      let omittedReal = (1...20).contains { text.contains("... and \($0) more") }
+      XCTAssertTrue(omittedReal, "omitted count should be <= 20 real activities, not include filtered cards")
+    }
+  }
+
+  // Boundary: when everything fits, there must be NO truncation notice
+  // (off-by-one guard on the `includedCount < ordered.count` check).
+  func testNoOmissionNoticeWhenAllCardsFit() {
+    let cards = (0..<3).map { card(title: "Task \($0)", minute: $0) }
+    let text = DailyRecapGenerator.makeCardsText(
+      day: "2026-06-16", cards: cards, maxCharacters: 10_000
+    )
+    XCTAssertFalse(text.contains("omitted"))
+    XCTAssertTrue(text.contains("3. 9:02am - 9:03am: Task 2"))
+  }
+
+  private func card(title: String, minute: Int, summary: String = "") -> TimelineCard {
+    TimelineCard(
+      recordId: nil, batchId: nil,
+      startTimestamp: String(format: "9:%02d AM", minute),
+      endTimestamp: String(format: "9:%02d AM", minute + 1),
+      category: "Work", subcategory: "Coding",
+      title: title, summary: summary, detailedSummary: "", day: "2026-06-16",
+      distractions: nil, videoSummaryURL: nil, otherVideoSummaryURLs: nil, appSites: nil
+    )
+  }
+}