diff --git a/models/actions/run_job_summary.go b/models/actions/run_job_summary.go
new file mode 100644
index 0000000000..63e913c7bb
--- /dev/null
+++ b/models/actions/run_job_summary.go
@@ -0,0 +1,207 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"context"
+
+	"gitea.dev/models/db"
+	"gitea.dev/modules/setting"
+	"gitea.dev/modules/timeutil"
+	"gitea.dev/modules/util"
+)
+
+const (
+	// JobSummaryCapability is the runner-declare capability string for job summaries.
+	JobSummaryCapability = "job-summary"
+
+	// JobSummaryContentTypeMarkdown is the only accepted content type for job summaries.
+	JobSummaryContentTypeMarkdown = "text/markdown"
+
+	// MaxJobSummarySize is the maximum accepted per-step summary payload size in bytes.
+	MaxJobSummarySize = 1024 * 1024 // 1 MiB
+
+	// MaxJobSummaryAggregateSize is the maximum aggregate size of all step summaries within
+	// a single job attempt. Matches GitHub's documented per-job summary cap of 1 MiB.
+	MaxJobSummaryAggregateSize = 1024 * 1024 // 1 MiB
+)
+
+// RunnerCapabilities returns the value advertised in the X-Gitea-Actions-Capabilities header.
+// When more capabilities are added, return them comma-separated so runners can split on ", ".
+func RunnerCapabilities() string {
+	return JobSummaryCapability
+}
+
+type ActionRunJobSummary struct {
+	ID int64 `xorm:"pk autoincr"`
+
+	RepoID       int64 `xorm:"UNIQUE(summary_key)"`
+	RunID        int64 `xorm:"UNIQUE(summary_key)"`
+	RunAttemptID int64 `xorm:"UNIQUE(summary_key) NOT NULL DEFAULT 0"`
+	JobID        int64 `xorm:"UNIQUE(summary_key)"`
+	StepIndex    int64 `xorm:"UNIQUE(summary_key)"`
+
+	Content     string `xorm:"LONGTEXT"`
+	ContentType string `xorm:"VARCHAR(255) NOT NULL DEFAULT 'text/markdown'"`
+	// ContentSize is the byte length of Content. Stored explicitly because LENGTH()
+	// counts characters (not bytes) on PostgreSQL, SQLite and MSSQL, which would let
+	// multibyte UTF-8 content bypass the aggregate cap.
+	ContentSize int64 `xorm:"NOT NULL DEFAULT 0"`
+
+	Created timeutil.TimeStamp `xorm:"created"`
+	Updated timeutil.TimeStamp `xorm:"updated"`
+}
+
+func init() {
+	db.RegisterModel(new(ActionRunJobSummary))
+}
+
+func GetActionRunJobSummary(ctx context.Context, repoID, runID, runAttemptID, jobID, stepIndex int64) (*ActionRunJobSummary, error) {
+	var s ActionRunJobSummary
+	has, err := db.GetEngine(ctx).
+		Where("repo_id=? AND run_id=? AND run_attempt_id=? AND job_id=? AND step_index=?", repoID, runID, runAttemptID, jobID, stepIndex).
+		Get(&s)
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		return nil, util.ErrNotExist
+	}
+	return &s, nil
+}
+
+// ErrJobSummaryAggregateExceeded is returned when a step summary upload would push the
+// aggregate size of summaries for a single job attempt over MaxJobSummaryAggregateSize.
+var ErrJobSummaryAggregateExceeded = util.NewInvalidArgumentErrorf("job summary aggregate size exceeded")
+
+func UpsertActionRunJobSummary(ctx context.Context, repoID, runID, runAttemptID, jobID, stepIndex int64, contentType string, content []byte) error {
+	if runID <= 0 || jobID <= 0 || repoID <= 0 || stepIndex < 0 {
+		return util.ErrInvalidArgument
+	}
+	if len(content) == 0 {
+		// Treat empty summaries as no-op; runner may create SUMMARY.md but never write to it.
+		return nil
+	}
+	if len(content) > MaxJobSummarySize {
+		return util.ErrInvalidArgument
+	}
+	if contentType != JobSummaryContentTypeMarkdown {
+		return util.ErrInvalidArgument
+	}
+
+	// The aggregate check is best-effort: a tx wouldn't actually serialize concurrent
+	// step uploads (no row-level lock on the parent job), so wrapping these two
+	// statements only adds round-trip cost without changing the race semantics.
+	// The current step is excluded because the upsert below replaces its size with len(content).
+	otherSize, err := sumOtherJobSummarySizes(ctx, repoID, runID, runAttemptID, jobID, stepIndex)
+	if err != nil {
+		return err
+	}
+	if otherSize+int64(len(content)) > MaxJobSummaryAggregateSize {
+		return ErrJobSummaryAggregateExceeded
+	}
+
+	now := timeutil.TimeStampNow()
+	return upsertActionRunJobSummary(ctx, &ActionRunJobSummary{
+		RepoID:       repoID,
+		RunID:        runID,
+		RunAttemptID: runAttemptID,
+		JobID:        jobID,
+		StepIndex:    stepIndex,
+		Content:      string(content),
+		ContentSize:  int64(len(content)),
+		ContentType:  contentType,
+		Created:      now,
+		Updated:      now,
+	})
+}
+
+// sumOtherJobSummarySizes returns the total stored size of all step summaries for a job
+// except excludeStepIndex, computed in the database to avoid loading every row.
+func sumOtherJobSummarySizes(ctx context.Context, repoID, runID, runAttemptID, jobID, excludeStepIndex int64) (int64, error) {
+	return db.GetEngine(ctx).
+		Where("repo_id=? AND run_id=? AND run_attempt_id=? AND job_id=? AND step_index<>?", repoID, runID, runAttemptID, jobID, excludeStepIndex).
+		SumInt(new(ActionRunJobSummary), "content_size")
+}
+
+// DeleteActionRunJobSummary removes the stored summary for a specific step. Used when
+// a runner PUTs an empty body to clear a previously-uploaded step summary.
+func DeleteActionRunJobSummary(ctx context.Context, repoID, runID, runAttemptID, jobID, stepIndex int64) error {
+	_, err := db.GetEngine(ctx).
+		Where("repo_id=? AND run_id=? AND run_attempt_id=? AND job_id=? AND step_index=?", repoID, runID, runAttemptID, jobID, stepIndex).
+		Delete(new(ActionRunJobSummary))
+	return err
+}
+
+func upsertActionRunJobSummary(ctx context.Context, summary *ActionRunJobSummary) error {
+	engine := db.GetEngine(ctx)
+	columns := "`repo_id`, `run_id`, `run_attempt_id`, `job_id`, `step_index`, `content`, `content_type`, `content_size`, `created`, `updated`"
+	values := []any{
+		summary.RepoID,
+		summary.RunID,
+		summary.RunAttemptID,
+		summary.JobID,
+		summary.StepIndex,
+		summary.Content,
+		summary.ContentType,
+		summary.ContentSize,
+		summary.Created,
+		summary.Updated,
+	}
+
+	if setting.Database.Type.IsPostgreSQL() || setting.Database.Type.IsSQLite3() {
+		args := append([]any{"INSERT INTO `action_run_job_summary` (" + columns + ") VALUES (?,?,?,?,?,?,?,?,?,?) " +
+			"ON CONFLICT (`repo_id`, `run_id`, `run_attempt_id`, `job_id`, `step_index`) DO UPDATE SET " +
+			"`content` = excluded.`content`, `content_type` = excluded.`content_type`, `content_size` = excluded.`content_size`, `updated` = excluded.`updated`"}, values...)
+		_, err := engine.Exec(args...)
+		return err
+	}
+
+	if setting.Database.Type.IsMySQL() {
+		args := append([]any{
+			"INSERT INTO `action_run_job_summary` (" + columns + ") VALUES (?,?,?,?,?,?,?,?,?,?) " +
+				"ON DUPLICATE KEY UPDATE `content` = VALUES(`content`), `content_type` = VALUES(`content_type`), `content_size` = VALUES(`content_size`), `updated` = VALUES(`updated`)",
+		}, values...)
+		_, err := engine.Exec(args...)
+		return err
+	}
+
+	if setting.Database.Type.IsMSSQL() {
+		_, err := engine.Exec(`
+MERGE INTO action_run_job_summary WITH (HOLDLOCK) AS target
+USING (SELECT ? AS repo_id, ? AS run_id, ? AS run_attempt_id, ? AS job_id, ? AS step_index) AS source
+ON target.repo_id = source.repo_id
+	AND target.run_id = source.run_id
+	AND target.run_attempt_id = source.run_attempt_id
+	AND target.job_id = source.job_id
+	AND target.step_index = source.step_index
+WHEN MATCHED THEN
+	UPDATE SET content = ?, content_type = ?, content_size = ?, updated = ?
+WHEN NOT MATCHED THEN
+	INSERT (repo_id, run_id, run_attempt_id, job_id, step_index, content, content_type, content_size, created, updated)
+	VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?);
+`,
+			summary.RepoID, summary.RunID, summary.RunAttemptID, summary.JobID, summary.StepIndex,
+			summary.Content, summary.ContentType, summary.ContentSize, summary.Updated,
+			summary.RepoID, summary.RunID, summary.RunAttemptID, summary.JobID, summary.StepIndex, summary.Content, summary.ContentType, summary.ContentSize, summary.Created, summary.Updated)
+		return err
+	}
+
+	return util.ErrInvalidArgument
+}
+
+// ListActionRunJobSummaries lists the stored summaries for a run attempt, ordered by job
+// then step. A positive jobID scopes the lookup to that single job, used by the job view to
+// avoid rendering every job's summary on each poll; jobID<=0 returns all jobs in the attempt.
+func ListActionRunJobSummaries(ctx context.Context, repoID, runID, runAttemptID, jobID int64) ([]*ActionRunJobSummary, error) {
+	sess := db.GetEngine(ctx).Where("repo_id=? AND run_id=? AND run_attempt_id=?", repoID, runID, runAttemptID)
+	if jobID > 0 {
+		sess = sess.And("job_id=?", jobID)
+	}
+	var summaries []*ActionRunJobSummary
+	if err := sess.OrderBy("job_id ASC, step_index ASC").Find(&summaries); err != nil {
+		return nil, err
+	}
+	return summaries, nil
+}
diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 904a3ffa20..aedd679c57 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -413,6 +413,7 @@ func prepareMigrationTasks() []*migration {
 		newMigration(333, "Add bypass allowlist to branch protection", v1_27.AddBranchProtectionBypassAllowlist),
 		newMigration(334, "Add cancelling support to action runners", v1_27.AddCancellingSupportToActionRunner),
 		newMigration(335, "Add reusable workflow fields and action_run_attempt_job_id_index table for ActionRunJob", v1_27.AddReusableWorkflowFieldsToActionRunJob),
+		newMigration(336, "Add ActionRunJobSummary table", v1_27.AddActionRunJobSummaryTable),
 	}
 	return preparedMigrations
 }
diff --git a/models/migrations/v1_27/v336.go b/models/migrations/v1_27/v336.go
new file mode 100644
index 0000000000..9c5e0c9494
--- /dev/null
+++ b/models/migrations/v1_27/v336.go
@@ -0,0 +1,30 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_27
+
+import (
+	"gitea.dev/models/db"
+	"gitea.dev/modules/timeutil"
+)
+
+func AddActionRunJobSummaryTable(x db.EngineMigration) error {
+	type ActionRunJobSummary struct {
+		ID int64 `xorm:"pk autoincr"`
+
+		RepoID       int64 `xorm:"UNIQUE(summary_key)"`
+		RunID        int64 `xorm:"UNIQUE(summary_key)"`
+		RunAttemptID int64 `xorm:"UNIQUE(summary_key) NOT NULL DEFAULT 0"`
+		JobID        int64 `xorm:"UNIQUE(summary_key)"`
+		StepIndex    int64 `xorm:"UNIQUE(summary_key)"`
+
+		Content     string `xorm:"LONGTEXT"`
+		ContentType string `xorm:"VARCHAR(255) NOT NULL DEFAULT 'text/markdown'"`
+		ContentSize int64  `xorm:"NOT NULL DEFAULT 0"`
+
+		Created timeutil.TimeStamp `xorm:"created"`
+		Updated timeutil.TimeStamp `xorm:"updated"`
+	}
+
+	return x.Sync(new(ActionRunJobSummary))
+}
diff --git a/options/locale/locale_en-US.json b/options/locale/locale_en-US.json
index a629f11adf..90c7c71fb7 100644
--- a/options/locale/locale_en-US.json
+++ b/options/locale/locale_en-US.json
@@ -3798,6 +3798,7 @@
   "actions.runs.view_workflow_file": "View workflow file",
   "actions.runs.summary": "Summary",
   "actions.runs.all_jobs": "All jobs",
+  "actions.runs.job_summaries": "Job summaries",
   "actions.runs.expand_caller_jobs": "Show jobs of this reusable workflow caller",
   "actions.runs.collapse_caller_jobs": "Hide jobs of this reusable workflow caller",
   "actions.runs.attempt": "Attempt",
diff --git a/routers/api/actions/artifacts.go b/routers/api/actions/artifacts.go
index d82ac6988c..eeea05c9b4 100644
--- a/routers/api/actions/artifacts.go
+++ b/routers/api/actions/artifacts.go
@@ -121,6 +121,9 @@ func ArtifactsRoutes(prefix string) *web.Router {
 		m.Get("/{artifact_id}/download", r.downloadArtifact)
 	})
 
+	// Job summary upload endpoint (GITHUB_STEP_SUMMARY).
+	m.Put(jobSummaryRouteBase, uploadJobSummary)
+
 	return m
 }
 
diff --git a/routers/api/actions/job_summary.go b/routers/api/actions/job_summary.go
new file mode 100644
index 0000000000..fa21cd6d11
--- /dev/null
+++ b/routers/api/actions/job_summary.go
@@ -0,0 +1,104 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"errors"
+	"io"
+	"mime"
+	"net/http"
+	"slices"
+	"strconv"
+
+	actions_model "gitea.dev/models/actions"
+	"gitea.dev/modules/log"
+	"gitea.dev/modules/util"
+)
+
+const jobSummaryRouteBase = "/_apis/pipelines/workflows/{run_id}/jobs/{job_id}/steps/{step_index}/summary"
+
+func uploadJobSummary(ctx *ArtifactContext) {
+	task, _, ok := validateRunID(ctx)
+	if !ok {
+		return
+	}
+
+	jobID := ctx.PathParamInt64("job_id")
+	if jobID <= 0 || task.Job.ID != jobID {
+		ctx.HTTPError(http.StatusBadRequest, "job_id mismatch")
+		return
+	}
+
+	stepIndex, err := strconv.ParseInt(ctx.PathParam("step_index"), 10, 64)
+	if err != nil || stepIndex < 0 {
+		ctx.HTTPError(http.StatusBadRequest, "invalid step_index")
+		return
+	}
+	steps, err := actions_model.GetTaskStepsByTaskID(ctx, task.ID)
+	if err != nil {
+		log.Error("Error getting task steps: %v", err)
+		ctx.HTTPError(http.StatusInternalServerError, "Error getting task steps")
+		return
+	}
+	if !slices.ContainsFunc(steps, func(s *actions_model.ActionTaskStep) bool { return s.Index == stepIndex }) {
+		ctx.HTTPError(http.StatusBadRequest, "step_index mismatch")
+		return
+	}
+
+	contentType, ok := normalizeJobSummaryContentType(ctx.Req.Header.Get("Content-Type"))
+	if !ok {
+		ctx.HTTPError(http.StatusBadRequest, "invalid summary content type")
+		return
+	}
+
+	body, err := io.ReadAll(io.LimitReader(ctx.Req.Body, actions_model.MaxJobSummarySize+1))
+	if err != nil {
+		log.Error("Error reading job summary request body: %v", err)
+		ctx.HTTPError(http.StatusInternalServerError, "read request body")
+		return
+	}
+	message := "success"
+	if len(body) == 0 {
+		// PUT with an empty body clears any previously-stored summary for this step.
+		if err := actions_model.DeleteActionRunJobSummary(ctx, task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, stepIndex); err != nil {
+			log.Error("Error deleting job summary: %v", err)
+			ctx.HTTPError(http.StatusInternalServerError, "Error deleting job summary")
+			return
+		}
+		message = "cleared"
+	} else if err := actions_model.UpsertActionRunJobSummary(ctx, task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, stepIndex, contentType, body); err != nil {
+		if errors.Is(err, actions_model.ErrJobSummaryAggregateExceeded) {
+			ctx.HTTPError(http.StatusBadRequest, "job summary aggregate size exceeded")
+			return
+		}
+		if errors.Is(err, util.ErrInvalidArgument) {
+			ctx.HTTPError(http.StatusBadRequest, "invalid summary")
+			return
+		}
+		log.Error("Error upsert job summary: %v", err)
+		ctx.HTTPError(http.StatusInternalServerError, "Error upsert job summary")
+		return
+	}
+
+	ctx.JSON(http.StatusOK, map[string]any{
+		"message":    message,
+		"sizeBytes":  len(body),
+		"runAttempt": task.Job.RunAttemptID,
+	})
+}
+
+func normalizeJobSummaryContentType(contentType string) (string, bool) {
+	if contentType == "" || contentType == "application/octet-stream" {
+		return actions_model.JobSummaryContentTypeMarkdown, true
+	}
+
+	mediaType, _, err := mime.ParseMediaType(contentType)
+	if err != nil {
+		return "", false
+	}
+	if mediaType != actions_model.JobSummaryContentTypeMarkdown {
+		return "", false
+	}
+	return actions_model.JobSummaryContentTypeMarkdown, true
+}
diff --git a/routers/api/actions/runner/runner.go b/routers/api/actions/runner/runner.go
index e98aef9515..803b7c13a1 100644
--- a/routers/api/actions/runner/runner.go
+++ b/routers/api/actions/runner/runner.go
@@ -161,7 +161,7 @@ func (s *Service) Declare(
 		return nil, status.Errorf(codes.Internal, "update runner: %v", err)
 	}
 
-	return connect.NewResponse(&runnerv1.DeclareResponse{
+	resp := connect.NewResponse(&runnerv1.DeclareResponse{
 		Runner: &runnerv1.Runner{
 			Id:      runner.ID,
 			Uuid:    runner.UUID,
@@ -170,7 +170,11 @@ func (s *Service) Declare(
 			Version: runner.Version,
 			Labels:  runner.AgentLabels,
 		},
-	}), nil
+	})
+	// Capabilities are communicated via headers to avoid a hard dependency on a proto bump.
+	// Older runners ignore unknown headers; newer runners can use this for feature negotiation.
+	resp.Header().Set("X-Gitea-Actions-Capabilities", actions_model.RunnerCapabilities())
+	return resp, nil
 }
 
 // FetchTask assigns a task to the runner
diff --git a/routers/web/devtest/mock_actions.go b/routers/web/devtest/mock_actions.go
index 185cdc8acb..bc6fdeb907 100644
--- a/routers/web/devtest/mock_actions.go
+++ b/routers/web/devtest/mock_actions.go
@@ -15,6 +15,7 @@ import (
 	actions_model "gitea.dev/models/actions"
 	user_model "gitea.dev/models/user"
 	"gitea.dev/modules/setting"
+	"gitea.dev/modules/templates"
 	"gitea.dev/modules/timeutil"
 	"gitea.dev/modules/util"
 	"gitea.dev/modules/web"
@@ -89,6 +90,7 @@ func MockActionsRunsJobs(ctx *context.Context) {
 	resp.State.Run.CanDeleteArtifact = true
 	resp.State.Run.WorkflowID = "workflow-id.yml"
 	resp.State.Run.TriggerEvent = "push"
+	renderUtils := templates.NewRenderUtils(ctx)
 	user2, _ := user_model.GetUserByID(ctx, 2)
 	if user2 == nil {
 		user2 = &user_model.User{Name: "user2"}
@@ -196,6 +198,20 @@ func MockActionsRunsJobs(ctx *context.Context) {
 	resp.State.Run.CanRerun = runID == 30 && isLatestAttempt
 	resp.State.Run.CanRerunFailed = runID == 30 && isLatestAttempt
 
+	// Mock job summaries so the devtest page can preview the Summary panel rendering.
+	resp.State.Run.JobSummaries = []*actions.ViewJobSummary{
+		{
+			JobID:       runID * 10,
+			JobName:     "job 100 (testsubname)",
+			SummaryHTML: renderUtils.MarkdownToHtml("### Devtest job summary\n\n- Markdown rendering\n- Links: [example](https://example.com)\n\n```sh\necho hello\n```\n"),
+		},
+		{
+			JobID:       runID*10 + 2,
+			JobName:     "ULTRA LOOOOOOOOOOOONG job name 102 that exceeds the limit",
+			SummaryHTML: renderUtils.MarkdownToHtml("### Another summary\n\nThis demonstrates multiple job summaries in one run.\n\n- Item A\n- Item B\n"),
+		},
+	}
+
 	resp.Artifacts = append(resp.Artifacts, &actions.ArtifactsViewItem{
 		Name:        "artifact-a",
 		Size:        100 * 1024,
diff --git a/routers/web/repo/actions/view.go b/routers/web/repo/actions/view.go
index 9f8477d4c0..2f4f1950ec 100644
--- a/routers/web/repo/actions/view.go
+++ b/routers/web/repo/actions/view.go
@@ -315,6 +315,8 @@ type ViewResponse struct {
 			Duration     string `json:"duration"`
 			TriggeredAt  int64  `json:"triggeredAt"`  // unix seconds for relative time
 			TriggerEvent string `json:"triggerEvent"` // e.g. pull_request, push, schedule
+
+			JobSummaries []*ViewJobSummary `json:"jobSummaries,omitempty"`
 		} `json:"run"`
 		CurrentJob struct {
 			Title  string         `json:"title"`
@@ -344,6 +346,12 @@ type ViewJob struct {
 	CallUses         string `json:"callUses,omitempty"`
 }
 
+type ViewJobSummary struct {
+	JobID       int64         `json:"jobId"`
+	JobName     string        `json:"jobName"`
+	SummaryHTML template.HTML `json:"summaryHTML"`
+}
+
 type ViewRunAttempt struct {
 	Attempt           int64  `json:"attempt"`
 	Status            string `json:"status"`
@@ -649,12 +657,42 @@ func fillViewRunResponseSummary(ctx *context_module.Context, resp *ViewResponse,
 	resp.State.Run.PullRequest = refInfo.PullRequest
 	resp.State.Run.TriggerEvent = run.TriggerEvent
 
-	// Legacy runs (LatestAttemptID == 0) have no attempt; their artifacts all share run_attempt_id=0,
-	// so passing 0 here scopes to this run's legacy artifacts only.
+	// Legacy runs (LatestAttemptID == 0) have no attempt; their artifacts and summaries all
+	// share run_attempt_id=0, so passing 0 here scopes to this run's legacy rows only.
 	var runAttemptID int64
 	if attempt != nil {
 		runAttemptID = attempt.ID
 	}
+
+	// Each step's markdown is rendered independently so an unclosed construct
+	// in one step can't bleed into the next.
+	// On a single-job view only that job's summaries are needed; the run view shows all.
+	// Scoping server-side avoids rendering every job's markdown on each 1s poll.
+	summaries, err := actions_model.ListActionRunJobSummaries(ctx, ctx.Repo.Repository.ID, run.ID, runAttemptID, ctx.PathParamInt64("job"))
+	if err != nil {
+		ctx.ServerError("ListActionRunJobSummaries", err)
+		return
+	}
+	if len(summaries) > 0 {
+		jobNameByID := make(map[int64]string, len(jobs))
+		for _, j := range jobs {
+			jobNameByID[j.ID] = j.Name
+		}
+		renderUtils := templates.NewRenderUtils(ctx)
+		var current *ViewJobSummary
+		for _, s := range summaries {
+			if s.ContentType != actions_model.JobSummaryContentTypeMarkdown {
+				log.Warn("Skip unsupported job summary content type %q for run %d job %d step %d", s.ContentType, s.RunID, s.JobID, s.StepIndex)
+				continue
+			}
+			if current == nil || current.JobID != s.JobID {
+				current = &ViewJobSummary{JobID: s.JobID, JobName: jobNameByID[s.JobID]}
+				resp.State.Run.JobSummaries = append(resp.State.Run.JobSummaries, current)
+			}
+			current.SummaryHTML += renderUtils.MarkdownToHtml(s.Content)
+		}
+	}
+
 	arts, err := actions_model.ListUploadedArtifactsMetaByRunAttempt(ctx, ctx.Repo.Repository.ID, run.ID, runAttemptID)
 	if err != nil {
 		ctx.ServerError("ListUploadedArtifactsMetaByRunAttempt", err)
diff --git a/services/actions/cleanup.go b/services/actions/cleanup.go
index dc8f13cdcb..7bf7c93dca 100644
--- a/services/actions/cleanup.go
+++ b/services/actions/cleanup.go
@@ -232,6 +232,10 @@ func DeleteRun(ctx context.Context, run *actions_model.ActionRun) error {
 		RepoID: repoID,
 		RunID:  run.ID,
 	})
+	recordsToDelete = append(recordsToDelete, &actions_model.ActionRunJobSummary{
+		RepoID: repoID,
+		RunID:  run.ID,
+	})
 
 	if err := db.WithTx(ctx, func(ctx context.Context) error {
 		// TODO: Deleting task records could break current ephemeral runner implementation. This is a temporary workaround suggested by ChristopherHX.
diff --git a/services/repository/delete.go b/services/repository/delete.go
index d1b41f980b..0666a1616b 100644
--- a/services/repository/delete.go
+++ b/services/repository/delete.go
@@ -177,6 +177,7 @@ func DeleteRepositoryDirectly(ctx context.Context, repoID int64, ignoreOrgTeams
 		&actions_model.ActionScheduleSpec{RepoID: repoID},
 		&actions_model.ActionSchedule{RepoID: repoID},
 		&actions_model.ActionArtifact{RepoID: repoID},
+		&actions_model.ActionRunJobSummary{RepoID: repoID},
 		&actions_model.ActionRunnerToken{RepoID: repoID},
 		&issues_model.IssuePin{RepoID: repoID},
 	); err != nil {
diff --git a/templates/repo/actions/view_component.tmpl b/templates/repo/actions/view_component.tmpl
index 8b8a6dfeff..0d508e69e5 100644
--- a/templates/repo/actions/view_component.tmpl
+++ b/templates/repo/actions/view_component.tmpl
@@ -15,6 +15,7 @@
 		data-locale-runs-pushed-by="{{ctx.Locale.Tr "actions.runs.pushed_by"}}"
 		data-locale-summary="{{ctx.Locale.Tr "actions.runs.summary"}}"
 		data-locale-all-jobs="{{ctx.Locale.Tr "actions.runs.all_jobs"}}"
+		data-locale-job-summaries="{{ctx.Locale.Tr "actions.runs.job_summaries"}}"
 		data-locale-expand-caller-jobs="{{ctx.Locale.Tr "actions.runs.expand_caller_jobs"}}"
 		data-locale-collapse-caller-jobs="{{ctx.Locale.Tr "actions.runs.collapse_caller_jobs"}}"
 		data-locale-triggered-via="{{ctx.Locale.Tr "actions.runs.triggered_via"}}"
diff --git a/tests/integration/actions_route_test.go b/tests/integration/actions_route_test.go
index 1591a17ae0..862656186b 100644
--- a/tests/integration/actions_route_test.go
+++ b/tests/integration/actions_route_test.go
@@ -63,18 +63,51 @@ jobs:
 	task2 := runner2.fetchTask(t)
 	_, job2, run2 := getTaskAndJobAndRunByTaskID(t, task2.Id)
 
+	require.NoError(t, actions_model.UpsertActionRunJobSummary(t.Context(), repo1.ID, run1.ID, job1.RunAttemptID, job1.ID, 0, "text/markdown", []byte("### Hello summary\n\nFrom first step.\n")))
+	require.NoError(t, actions_model.UpsertActionRunJobSummary(t.Context(), repo1.ID, run1.ID, job1.RunAttemptID, job1.ID, 1, "text/markdown", []byte("From second step.\n")))
+	// A second job's summary in the same run/attempt: the run view must include it,
+	// but the single-job view must scope it out.
+	otherJobID := job1.ID + 1
+	require.NoError(t, actions_model.UpsertActionRunJobSummary(t.Context(), repo1.ID, run1.ID, job1.RunAttemptID, otherJobID, 0, "text/markdown", []byte("### Other job summary\n")))
+
 	req := NewRequest(t, "GET", fmt.Sprintf("/%s/%s/actions/runs/%d", user2.Name, repo1.Name, run1.ID))
 	user2Session.MakeRequest(t, req, http.StatusOK)
 
 	req = NewRequest(t, "GET", fmt.Sprintf("/%s/%s/actions/runs/%d", user2.Name, repo1.Name, 999999))
 	user2Session.MakeRequest(t, req, http.StatusNotFound)
 
-	// run1 and job1 belong to repo1, success
-	req = NewRequest(t, "POST", fmt.Sprintf("/%s/%s/actions/runs/%d/jobs/%d", user2.Name, repo1.Name, run1.ID, job1.ID))
+	findSummary := func(viewResp *actions_web.ViewResponse, jobID int64) *actions_web.ViewJobSummary {
+		for _, s := range viewResp.State.Run.JobSummaries {
+			if s.JobID == jobID {
+				return s
+			}
+		}
+		return nil
+	}
+	assertJob1Summary := func(t *testing.T, s *actions_web.ViewJobSummary) {
+		t.Helper()
+		require.NotNil(t, s)
+		assert.Contains(t, string(s.SummaryHTML), "Hello summary")
+		assert.Contains(t, string(s.SummaryHTML), "From second step")
+	}
+
+	// Run view: summaries for every job in the run.
+	req = NewRequest(t, "POST", fmt.Sprintf("/%s/%s/actions/runs/%d", user2.Name, repo1.Name, run1.ID))
 	resp := user2Session.MakeRequest(t, req, http.StatusOK)
 	viewResp := DecodeJSON(t, resp, &actions_web.ViewResponse{})
+	require.Len(t, viewResp.State.Run.JobSummaries, 2)
+	assertJob1Summary(t, findSummary(viewResp, job1.ID))
+	assert.Contains(t, string(findSummary(viewResp, otherJobID).SummaryHTML), "Other job summary")
+
+	// Job view: scoped server-side to the requested job, the other job's summary excluded.
+	req = NewRequest(t, "POST", fmt.Sprintf("/%s/%s/actions/runs/%d/jobs/%d", user2.Name, repo1.Name, run1.ID, job1.ID))
+	resp = user2Session.MakeRequest(t, req, http.StatusOK)
+	viewResp = DecodeJSON(t, resp, &actions_web.ViewResponse{})
 	assert.Len(t, viewResp.State.Run.Jobs, 1)
 	assert.Equal(t, job1.ID, viewResp.State.Run.Jobs[0].ID)
+	require.Len(t, viewResp.State.Run.JobSummaries, 1)
+	assertJob1Summary(t, findSummary(viewResp, job1.ID))
+	assert.Nil(t, findSummary(viewResp, otherJobID))
 
 	// run2 and job2 do not belong to repo1, failure
 	req = NewRequest(t, "POST", fmt.Sprintf("/%s/%s/actions/runs/%d/jobs/%d", user2.Name, repo1.Name, run2.ID, job2.ID))
diff --git a/tests/integration/api_actions_artifact_test.go b/tests/integration/api_actions_artifact_test.go
index 9e8444525f..75b91b6135 100644
--- a/tests/integration/api_actions_artifact_test.go
+++ b/tests/integration/api_actions_artifact_test.go
@@ -17,10 +17,13 @@ import (
 	"testing"
 
 	runnerv1 "gitea.dev/actions-proto-go/runner/v1"
+	actions_model "gitea.dev/models/actions"
 	auth_model "gitea.dev/models/auth"
+	"gitea.dev/models/db"
 	repo_model "gitea.dev/models/repo"
 	"gitea.dev/models/unittest"
 	user_model "gitea.dev/models/user"
+	"gitea.dev/modules/util"
 	"gitea.dev/tests"
 
 	"github.com/stretchr/testify/assert"
@@ -44,6 +47,148 @@ func prepareTestEnvActionsArtifacts(t *testing.T) func() {
 	return f
 }
 
+func getArtifactFixtureTask(t *testing.T) *actions_model.ActionTask {
+	t.Helper()
+
+	task, err := actions_model.GetRunningTaskByToken(t.Context(), "8061e833a55f6fc0157c98b883e91fcfeeb1a71a")
+	require.NoError(t, err)
+	require.NoError(t, task.LoadJob(t.Context()))
+	ensureArtifactFixtureTaskSteps(t, task)
+	return task
+}
+
+func ensureArtifactFixtureTaskSteps(t *testing.T, task *actions_model.ActionTask) {
+	t.Helper()
+
+	steps, err := actions_model.GetTaskStepsByTaskID(t.Context(), task.ID)
+	require.NoError(t, err)
+
+	existingIndexes := make(map[int64]bool, len(steps))
+	for _, step := range steps {
+		existingIndexes[step.Index] = true
+	}
+
+	var stepsToInsert []*actions_model.ActionTaskStep
+	for _, idx := range []int64{0, 1} {
+		if existingIndexes[idx] {
+			continue
+		}
+		stepsToInsert = append(stepsToInsert, &actions_model.ActionTaskStep{
+			TaskID: task.ID,
+			Index:  idx,
+			RepoID: task.RepoID,
+			Status: actions_model.StatusWaiting,
+		})
+	}
+	if len(stepsToInsert) == 0 {
+		return
+	}
+
+	_, err = db.GetEngine(t.Context()).Insert(stepsToInsert)
+	require.NoError(t, err)
+}
+
+func TestActionsJobSummaryUpload(t *testing.T) {
+	defer prepareTestEnvActionsArtifacts(t)()
+
+	const runnerToken = "8061e833a55f6fc0157c98b883e91fcfeeb1a71a"
+	task := getArtifactFixtureTask(t)
+	summaryURL := func(stepIndex int64) string {
+		return fmt.Sprintf("/api/actions_pipeline/_apis/pipelines/workflows/%d/jobs/%d/steps/%d/summary", task.Job.RunID, task.Job.ID, stepIndex)
+	}
+	putSummary := func(stepIndex int64, body, contentType string) *RequestWrapper {
+		return NewRequestWithBody(t, "PUT", summaryURL(stepIndex), strings.NewReader(body)).
+			AddTokenAuth(runnerToken).
+			SetHeader("Content-Type", contentType)
+	}
+
+	t.Run("success", func(t *testing.T) {
+		body := "### Uploaded summary\n\n- line one\n"
+		MakeRequest(t, putSummary(0, body, "text/markdown; charset=utf-8"), http.StatusOK)
+
+		summary, err := actions_model.GetActionRunJobSummary(t.Context(), task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, 0)
+		require.NoError(t, err)
+		assert.Equal(t, actions_model.JobSummaryContentTypeMarkdown, summary.ContentType)
+		assert.Equal(t, body, summary.Content)
+
+		staleUpdated := summary.Updated - 60
+		_, err = db.GetEngine(t.Context()).ID(summary.ID).Cols("updated").Update(&actions_model.ActionRunJobSummary{Updated: staleUpdated})
+		require.NoError(t, err)
+
+		updatedBody := "### Updated summary\n\n- refreshed\n"
+		MakeRequest(t, putSummary(0, updatedBody, actions_model.JobSummaryContentTypeMarkdown), http.StatusOK)
+
+		summary, err = actions_model.GetActionRunJobSummary(t.Context(), task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, 0)
+		require.NoError(t, err)
+		assert.Equal(t, updatedBody, summary.Content)
+		assert.Greater(t, summary.Updated, staleUpdated)
+
+		stepTwoBody := "### Second step summary\n\n- another step\n"
+		MakeRequest(t, putSummary(1, stepTwoBody, actions_model.JobSummaryContentTypeMarkdown), http.StatusOK)
+
+		summary, err = actions_model.GetActionRunJobSummary(t.Context(), task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, 1)
+		require.NoError(t, err)
+		assert.Equal(t, stepTwoBody, summary.Content)
+
+		summaries, err := actions_model.ListActionRunJobSummaries(t.Context(), task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, 0)
+		require.NoError(t, err)
+		require.Len(t, summaries, 2)
+		assert.Equal(t, int64(0), summaries[0].StepIndex)
+		assert.Equal(t, int64(1), summaries[1].StepIndex)
+	})
+
+	t.Run("invalid-content-type", func(t *testing.T) {
+		resp := MakeRequest(t, putSummary(0, "summary", "text/html"), http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "invalid summary content type")
+	})
+
+	t.Run("size-limit", func(t *testing.T) {
+		resp := MakeRequest(t, putSummary(0, strings.Repeat("a", actions_model.MaxJobSummarySize+1), actions_model.JobSummaryContentTypeMarkdown), http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "invalid summary")
+	})
+
+	t.Run("aggregate-size-limit", func(t *testing.T) {
+		require.NoError(t, actions_model.UpsertActionRunJobSummary(t.Context(), task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, 0,
+			actions_model.JobSummaryContentTypeMarkdown, []byte(strings.Repeat("a", actions_model.MaxJobSummaryAggregateSize-1024))))
+		resp := MakeRequest(t, putSummary(1, strings.Repeat("b", 4096), actions_model.JobSummaryContentTypeMarkdown), http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "aggregate size exceeded")
+	})
+
+	t.Run("job-mismatch", func(t *testing.T) {
+		req := NewRequestWithBody(t, "PUT", fmt.Sprintf("/api/actions_pipeline/_apis/pipelines/workflows/%d/jobs/%d/steps/0/summary", task.Job.RunID, task.Job.ID+1), strings.NewReader("summary")).
+			AddTokenAuth(runnerToken).
+			SetHeader("Content-Type", actions_model.JobSummaryContentTypeMarkdown)
+		resp := MakeRequest(t, req, http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "job_id mismatch")
+	})
+
+	t.Run("run-mismatch", func(t *testing.T) {
+		req := NewRequestWithBody(t, "PUT", fmt.Sprintf("/api/actions_pipeline/_apis/pipelines/workflows/%d/jobs/%d/steps/0/summary", task.Job.RunID+1, task.Job.ID), strings.NewReader("summary")).
+			AddTokenAuth(runnerToken).
+			SetHeader("Content-Type", actions_model.JobSummaryContentTypeMarkdown)
+		resp := MakeRequest(t, req, http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "run-id does not match")
+	})
+
+	t.Run("invalid-step-index", func(t *testing.T) {
+		resp := MakeRequest(t, putSummary(-1, "summary", actions_model.JobSummaryContentTypeMarkdown), http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "invalid step_index")
+	})
+
+	t.Run("step-index-mismatch", func(t *testing.T) {
+		resp := MakeRequest(t, putSummary(999, "summary", actions_model.JobSummaryContentTypeMarkdown), http.StatusBadRequest)
+		assert.Contains(t, resp.Body.String(), "step_index mismatch")
+	})
+
+	t.Run("empty-body-clears", func(t *testing.T) {
+		MakeRequest(t, putSummary(0, "### keep me", actions_model.JobSummaryContentTypeMarkdown), http.StatusOK)
+		MakeRequest(t, putSummary(0, "", actions_model.JobSummaryContentTypeMarkdown), http.StatusOK)
+
+		_, err := actions_model.GetActionRunJobSummary(t.Context(), task.Job.RepoID, task.Job.RunID, task.Job.RunAttemptID, task.Job.ID, 0)
+		require.ErrorIs(t, err, util.ErrNotExist)
+	})
+}
+
 func TestActionsArtifactUploadSingleFile(t *testing.T) {
 	defer prepareTestEnvActionsArtifacts(t)()
 
diff --git a/web_src/js/components/ActionRunView.ts b/web_src/js/components/ActionRunView.ts
index 70508c74fb..582ae0431f 100644
--- a/web_src/js/components/ActionRunView.ts
+++ b/web_src/js/components/ActionRunView.ts
@@ -128,6 +128,7 @@ export function createEmptyActionsRun(): ActionsRun {
     triggerEvent: '',
     pullRequest: null,
     jobs: [] as Array<ActionsJob>,
+    jobSummaries: [],
     commit: {
       localeCommit: '',
       localePushedBy: '',
diff --git a/web_src/js/components/RepoActionView.vue b/web_src/js/components/RepoActionView.vue
index 7803a011be..03d62bd7cc 100644
--- a/web_src/js/components/RepoActionView.vue
+++ b/web_src/js/components/RepoActionView.vue
@@ -22,6 +22,11 @@ const props = defineProps<{
 const locale = props.locale;
 const store = createActionRunViewStore(props.actionsViewUrl);
 const {currentRun: run, runArtifacts: artifacts} = toRefs(store.viewData);
+const visibleJobSummaries = computed(() => {
+  const summaries = run.value.jobSummaries || [];
+  if (!props.jobId) return summaries;
+  return summaries.filter((summary) => summary.jobId === props.jobId);
+});
 
 type JobListItem = {
   job: ActionsJob;
@@ -277,19 +282,35 @@ async function deleteArtifact(name: string) {
       </div>
 
       <div class="action-view-right">
-        <ActionRunSummaryView
-          v-if="!props.jobId"
-          :store="store"
-          :locale="locale"
-          :artifact-count="artifacts.length"
-        />
-        <ActionRunJobView
-          v-else
-          :store="store"
-          :locale="locale"
-          :actions-view-url="props.actionsViewUrl"
-          :job-id="props.jobId"
-        />
+        <div class="action-view-right-panel">
+          <ActionRunSummaryView
+            v-if="!props.jobId"
+            :store="store"
+            :locale="locale"
+            :artifact-count="artifacts.length"
+          />
+          <ActionRunJobView
+            v-else
+            :store="store"
+            :locale="locale"
+            :actions-view-url="props.actionsViewUrl"
+            :job-id="props.jobId"
+          />
+        </div>
+        <div v-if="visibleJobSummaries.length" class="action-view-right-panel job-summary-section">
+          <div class="job-summary-section-header">
+            {{ locale.jobSummaries }}
+          </div>
+          <div class="job-summary-list">
+            <div v-for="s in visibleJobSummaries" :key="s.jobId" class="job-summary-item">
+              <div class="job-summary-header">
+                <strong class="gt-ellipsis">{{ s.jobName || `Job ${s.jobId}` }}</strong>
+              </div>
+              <!-- eslint-disable-next-line vue/no-v-html -->
+              <div class="markup job-summary-body" v-html="s.summaryHTML"/>
+            </div>
+          </div>
+        </div>
       </div>
     </div>
   </div>
@@ -463,25 +484,32 @@ async function deleteArtifact(name: string) {
   width: 70%;
   display: flex;
   flex-direction: column;
+  gap: 12px;
+}
+
+.action-view-right-panel {
   border: 1px solid var(--color-console-border);
   border-radius: var(--border-radius);
   background: var(--color-console-bg);
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
 }
 
 /* begin fomantic button overrides */
 
-.action-view-right .ui.button,
-.action-view-right .ui.button:focus {
+.action-view-right-panel .ui.button,
+.action-view-right-panel .ui.button:focus {
   background: transparent;
   color: var(--color-console-fg-subtle);
 }
 
-.action-view-right .ui.button:hover {
+.action-view-right-panel .ui.button:hover {
   background: var(--color-console-hover-bg);
   color: var(--color-console-fg);
 }
 
-.action-view-right .ui.button:active {
+.action-view-right-panel .ui.button:active {
   background: var(--color-console-active-bg);
   color: var(--color-console-fg);
 }
@@ -499,4 +527,39 @@ async function deleteArtifact(name: string) {
     max-width: none;
   }
 }
+
+.job-summary-section {
+  overflow: hidden;
+}
+
+.job-summary-section-header {
+  padding: 12px;
+  border-bottom: 1px solid var(--color-console-border);
+  background: var(--color-console-bg);
+  color: var(--color-console-fg);
+  font-weight: var(--font-weight-semibold);
+}
+
+.job-summary-list {
+  padding: 12px;
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+
+.job-summary-item {
+  padding: 12px;
+  border-radius: var(--border-radius);
+  background: var(--color-console-hover-bg);
+  border: 1px solid var(--color-console-border);
+}
+
+.job-summary-header {
+  color: var(--color-console-fg);
+  margin-bottom: 8px;
+}
+
+.job-summary-body {
+  color: var(--color-console-fg);
+}
 </style>
diff --git a/web_src/js/features/repo-actions.ts b/web_src/js/features/repo-actions.ts
index 5d114ea925..3d4bd49a4f 100644
--- a/web_src/js/features/repo-actions.ts
+++ b/web_src/js/features/repo-actions.ts
@@ -27,6 +27,7 @@ export function initRepositoryActionView() {
       pushedBy: el.getAttribute('data-locale-runs-pushed-by'),
       summary: el.getAttribute('data-locale-summary'),
       allJobs: el.getAttribute('data-locale-all-jobs'),
+      jobSummaries: el.getAttribute('data-locale-job-summaries'),
       expandCallerJobs: el.getAttribute('data-locale-expand-caller-jobs'),
       collapseCallerJobs: el.getAttribute('data-locale-collapse-caller-jobs'),
       triggeredVia: el.getAttribute('data-locale-triggered-via'),
diff --git a/web_src/js/modules/gitea-actions.ts b/web_src/js/modules/gitea-actions.ts
index 6446a58d11..bdaac6ef81 100644
--- a/web_src/js/modules/gitea-actions.ts
+++ b/web_src/js/modules/gitea-actions.ts
@@ -28,6 +28,7 @@ export type ActionsRun = {
     link: string,
   } | null,
   jobs: Array<ActionsJob>,
+  jobSummaries?: Array<ActionsJobSummary>,
   commit: {
     localeCommit: string,
     localePushedBy: string,
@@ -46,6 +47,12 @@ export type ActionsRun = {
   },
 };
 
+export type ActionsJobSummary = {
+  jobId: number,
+  jobName: string,
+  summaryHTML: string,
+};
+
 export type ActionsRunAttempt = {
   attempt: number;
   status: ActionsStatus;