diff --git a/apps/server/internal/platform/account_content_test.go b/apps/server/internal/platform/account_content_test.go
index 7046bf59e..441dbca5c 100644
--- a/apps/server/internal/platform/account_content_test.go
+++ b/apps/server/internal/platform/account_content_test.go
@@ -1,6 +1,9 @@
 package platform
 
 import (
+	"fmt"
+	"net/http"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -8,6 +11,66 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// The discovery job asks for pages no smaller than MinPageSize and rejects a
+// page with more items than it asked for. Lemmy, PieFed, and PeerTube read
+// fixed-size pages, so the smallest page they accept must be that size.
+func TestFixedPageDiscoveryNeverReturnsMoreThanTheSmallestRequestedPage(t *testing.T) {
+	originalClient := httpClient
+	defer func() { httpClient = originalClient }()
+
+	const instanceURL = "https://fed.example"
+	published := time.Now().UTC().Add(-time.Hour).Format(time.RFC3339)
+	full := func(limit string, item func(id int) string) string {
+		size, _ := strconv.Atoi(limit)
+		items := make([]string, 0, size)
+		for id := 1; id <= size; id++ {
+			items = append(items, item(id))
+		}
+		return strings.Join(items, ",")
+	}
+	httpClient = &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+		query := req.URL.Query()
+		switch req.URL.Path {
+		case "/api/v3/user":
+			return jsonResponse(req, `{"posts":[`+full(query.Get("limit"), func(id int) string {
+				return fmt.Sprintf(`{"post":{"id":%d,"name":"Post","ap_id":"%s/post/%d","published":%q}}`, id, instanceURL, id, published)
+			})+`]}`), nil
+		case "/api/alpha/post/list":
+			return jsonResponse(req, `{"posts":[`+full(query.Get("limit"), func(id int) string {
+				return fmt.Sprintf(`{"post":{"id":%d,"title":"Post","ap_id":"%s/post/%d","published":%q}}`, id, instanceURL, id, published)
+			})+`],"next_page":"2"}`), nil
+		case "/api/v1/video-channels/demos/videos":
+			return jsonResponse(req, `{"total":1000,"data":[`+full(query.Get("count"), func(id int) string {
+				return fmt.Sprintf(`{"uuid":"uuid-%d","name":"Video","publishedAt":%q}`, id, published)
+			})+`]}`), nil
+		}
+		return jsonResponseWithStatus(req, http.StatusNotFound, `{}`), nil
+	})}
+
+	tests := []struct {
+		name       string
+		discoverer AccountContentDiscoverer
+		accountID  string
+	}{
+		{name: "lemmy", discoverer: NewLemmyAdapter(instanceURL), accountID: "5"},
+		{name: "piefed", discoverer: NewPieFedAdapter(instanceURL), accountID: "5"},
+		{name: "peertube", discoverer: NewPeerTubeAdapter(instanceURL), accountID: "demos"},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			support := test.discoverer.AccountContentDiscoverySupport(AnalyticsAccountContext{AccountID: test.accountID})
+			require.True(t, support.Supported)
+			smallest := max(1, support.MinPageSize)
+			page, err := test.discoverer.DiscoverAccountContent(t.Context(), "token", AccountContentDiscoveryRequest{
+				AccountID: test.accountID, PageSize: smallest, PublishedAfter: time.Now().UTC().Add(-90 * 24 * time.Hour),
+			})
+			require.NoError(t, err)
+			require.NotEmpty(t, page.Items)
+			require.LessOrEqual(t, len(page.Items), smallest, "a page must fit the smallest page size the adapter declares")
+		})
+	}
+}
+
 func TestNormalizeAccountContentItemBoundsTextAndRejectsUnsafeProviderURLs(t *testing.T) {
 	t.Parallel()
 
diff --git a/apps/server/internal/platform/lemmy.go b/apps/server/internal/platform/lemmy.go
index bb3708f5c..a5f2a5314 100644
--- a/apps/server/internal/platform/lemmy.go
+++ b/apps/server/internal/platform/lemmy.go
@@ -577,7 +577,8 @@ func (l *LemmyAdapter) AccountContentDiscoverySupport(input AnalyticsAccountCont
 	if strings.TrimSpace(input.AccountID) == "" {
 		return AccountContentDiscoverySupport{UnavailableReason: "Lemmy account content discovery requires a stable account identity."}
 	}
-	return AccountContentDiscoverySupport{Supported: true, MaxPageSize: 20}
+	// Pages are numbered at a fixed size, so the job must not ask for less.
+	return AccountContentDiscoverySupport{Supported: true, MinPageSize: lemmyAccountContentPageSize, MaxPageSize: lemmyAccountContentPageSize}
 }
 
 func (l *LemmyAdapter) DiscoverAccountContent(ctx context.Context, accessToken string, input AccountContentDiscoveryRequest) (AccountContentPage, error) {
diff --git a/apps/server/internal/platform/peertube.go b/apps/server/internal/platform/peertube.go
index 573fab5ec..6f95b1546 100644
--- a/apps/server/internal/platform/peertube.go
+++ b/apps/server/internal/platform/peertube.go
@@ -827,7 +827,8 @@ func (p *PeerTubeAdapter) AccountContentDiscoverySupport(input AnalyticsAccountC
 	if strings.TrimSpace(input.AccountID) == "" {
 		return AccountContentDiscoverySupport{UnavailableReason: "PeerTube account content discovery requires a channel."}
 	}
-	return AccountContentDiscoverySupport{Supported: true, MaxPageSize: 25}
+	// Every page is read at a fixed count, so the job must not ask for less.
+	return AccountContentDiscoverySupport{Supported: true, MinPageSize: 25, MaxPageSize: 25}
 }
 
 type peertubeChannelVideo struct {
diff --git a/apps/server/internal/platform/piefed.go b/apps/server/internal/platform/piefed.go
index 8197dab17..a3fcda44e 100644
--- a/apps/server/internal/platform/piefed.go
+++ b/apps/server/internal/platform/piefed.go
@@ -548,7 +548,8 @@ func (p *PieFedAdapter) AccountContentDiscoverySupport(input AnalyticsAccountCon
 	if strings.TrimSpace(input.AccountID) == "" {
 		return AccountContentDiscoverySupport{UnavailableReason: "PieFed account content discovery requires a stable account identity."}
 	}
-	return AccountContentDiscoverySupport{Supported: true, MaxPageSize: 20}
+	// Pages are numbered at a fixed size, so the job must not ask for less.
+	return AccountContentDiscoverySupport{Supported: true, MinPageSize: 20, MaxPageSize: 20}
 }
 
 func (p *PieFedAdapter) DiscoverAccountContent(ctx context.Context, accessToken string, input AccountContentDiscoveryRequest) (AccountContentPage, error) {
diff --git a/changes/discovery-fixed-page-size.md b/changes/discovery-fixed-page-size.md
new file mode 100644
index 000000000..fe0c59d88
--- /dev/null
+++ b/changes/discovery-fixed-page-size.md
@@ -0,0 +1,3 @@
+### Fixed
+
+- Lemmy, PieFed, and PeerTube accounts with more than 250 posts or videos in the last 90 days finish their initial content discovery. The last page before the 250-item limit was rejected as oversized, so discovery failed on the same page every hour and never reached routine cycles.