From b4c1dbab37d628dd30522cd35a93c6f5121e0dec Mon Sep 17 00:00:00 2001
From: Ian Gulliver <git@flamingcow.io>
Date: Wed, 21 Oct 2026 14:45:19 -0700
Subject: [PATCH] Log slow API requests with server spans and client timing

---
 docs/operations.md                   |   4 +
 internal/agents/audit.go             |   2 +-
 internal/agents/critical.go          |   4 +-
 internal/agents/inbox.go             |   4 +-
 internal/agents/leadtools.go         |   4 +-
 internal/agents/maincommit.go        |   8 +-
 internal/agents/manager.go           |   8 +-
 internal/agents/mergefacts.go        |   6 +-
 internal/agents/mergein.go           |   4 +-
 internal/agents/mergemain.go         |   6 +-
 internal/agents/review.go            |   8 +-
 internal/agents/snapshots.go         |   6 +-
 internal/agents/subtasks.go          |   6 +-
 internal/agents/tasks.go             |   6 +-
 internal/agents/workflows.go         |   4 +-
 internal/git/changes.go              |  37 +++----
 internal/git/git.go                  | 138 ++++++++++++++-------------
 internal/git/ignore.go               |   4 +-
 internal/git/notes.go                |  29 +++---
 internal/git/rename.go               |  41 ++++----
 internal/git/snapshot.go             |  19 ++--
 internal/server/changes.go           |   6 +-
 internal/server/files.go             |   2 +-
 internal/server/server.go            |  13 ++-
 internal/server/timing.go            |  50 ++++++++++
 internal/store/migrateids.go         |   7 +-
 internal/store/store.go              |   8 +-
 internal/store/traced.go             |  95 ++++++++++++++++++
 internal/trace/trace.go              |  71 ++++++++++++++
 mac/Sources/Byre/API.swift           |   2 +-
 mac/Sources/Byre/RequestTiming.swift |  41 ++++++++
 31 files changed, 458 insertions(+), 185 deletions(-)
 create mode 100644 internal/server/timing.go
 create mode 100644 internal/store/traced.go
 create mode 100644 internal/trace/trace.go
 create mode 100644 mac/Sources/Byre/RequestTiming.swift

diff --git a/docs/operations.md b/docs/operations.md
index 7b6cece..0884dca 100644
--- a/docs/operations.md
+++ b/docs/operations.md
@@ -18,6 +18,10 @@ The service always runs from the app: `/Applications/Byre.app/Contents/Helpers/b
 
 `byre serve` exits when its executable is replaced (logging `executable replaced, exiting`) and launchd starts the new one. A missing path counts as not yet replaced, so the moment in `install.sh` between removing the old bundle and moving the new one in doesn't trigger it. The service log is owner-only (0600), including existing logs: Tailscale can put a sign-in URL there. Logs go to `~/Library/Logs/byre.log`; `launchctl print gui/$(id -u)/run.fc.byre` shows the service.
 
+## Slow requests
+
+An API request that takes 200 ms or more is logged on both ends. The server's line, `request slow`, in `byre.log`, has the handler's time and its spans: each git process, SQL begin, exec and query, the wait for the store's write lock, and the tailnet `whois`. Every response also carries these spans in a `Server-Timing` header. On the client, `log show --start <time> --predicate 'subsystem == "run.fc.byre.mac" AND eventMessage BEGINSWITH "request slow"'` shows the app's line, which splits the request's time into `queue` (waiting for a connection), `connect`, `network` (time to the first byte, less the server's time), `server`, `download` and `app` (how long the main actor took to pick up work once the response ended). Event streams and websockets are left out.
+
 ## Tailnet
 
 byre runs its own tailnet node with `tsnet`; it doesn't use the Tailscale app. The app connects at the root of the node's `ts.net` name on 443, not under a path: the API uses absolute paths and the app takes an origin with no path. Tailnet access requires a user identity; a tagged node gets 403. Local scripts can also check server status and run client commands through the authenticated loopback address.
diff --git a/internal/agents/audit.go b/internal/agents/audit.go
index 81e7757..d10f493 100644
--- a/internal/agents/audit.go
+++ b/internal/agents/audit.go
@@ -77,7 +77,7 @@ func (m *Manager) startAudit(ctx context.Context, projectID string) error {
 	if err != nil || active {
 		return err
 	}
-	head, err := git.BranchHead(project.RepoPath, project.DefaultBranch)
+	head, err := git.BranchHead(ctx, project.RepoPath, project.DefaultBranch)
 	if err != nil {
 		return err
 	}
diff --git a/internal/agents/critical.go b/internal/agents/critical.go
index 363fb65..97819e7 100644
--- a/internal/agents/critical.go
+++ b/internal/agents/critical.go
@@ -54,7 +54,7 @@ func (m *Manager) recoverMergeTurns(ctx context.Context, running []api.AgentSess
 		if err != nil {
 			return err
 		}
-		merging, err := git.MergeInProgress(task.WorktreePath)
+		merging, err := git.MergeInProgress(ctx, task.WorktreePath)
 		if err != nil {
 			return err
 		}
@@ -74,7 +74,7 @@ func (m *Manager) endMergeTurn(sessionID string, abort bool) {
 		return
 	}
 	if abort {
-		err := git.AbortMerge(t.dir)
+		err := git.AbortMerge(context.Background(), t.dir)
 		if err != nil {
 			slog.Error("abort unfinished merge", "session", sessionID, "err", err)
 		}
diff --git a/internal/agents/inbox.go b/internal/agents/inbox.go
index 69c7f4d..da9968d 100644
--- a/internal/agents/inbox.go
+++ b/internal/agents/inbox.go
@@ -161,7 +161,7 @@ func (m *Manager) ask(ctx context.Context, l *live, raw json.RawMessage) (string
 	if err != nil {
 		return "", err
 	}
-	behind, err := git.Behind(task.WorktreePath, project.DefaultBranch)
+	behind, err := git.Behind(ctx, task.WorktreePath, project.DefaultBranch)
 	if err != nil {
 		slog.Error("count commits behind default branch", "task", task.Id, "err", err)
 	}
@@ -182,7 +182,7 @@ func (m *Manager) ask(ctx context.Context, l *live, raw json.RawMessage) (string
 func (m *Manager) commitBeforeSync(ctx context.Context, l *live, branch string) error {
 	unlock := m.lockTask(l.taskID)
 	defer unlock()
-	_, err := git.CommitAll(l.dir, "Work before merging "+branch, l.gitName, l.gitEmail)
+	_, err := git.CommitAll(ctx, l.dir, "Work before merging "+branch, l.gitName, l.gitEmail)
 	if err != nil {
 		return err
 	}
diff --git a/internal/agents/leadtools.go b/internal/agents/leadtools.go
index ecac97b..2cda9f3 100644
--- a/internal/agents/leadtools.go
+++ b/internal/agents/leadtools.go
@@ -278,7 +278,7 @@ func (m *Manager) leadTools(l *live) []mcp.Tool {
 					if err != nil {
 						return "", err
 					}
-					base, err = git.Head(from.WorktreePath)
+					base, err = git.Head(ctx, from.WorktreePath)
 					if err != nil {
 						return "", err
 					}
@@ -970,7 +970,7 @@ func (m *Manager) listTasksText(ctx context.Context) (string, error) {
 		if !listed {
 			b.WriteString("- no active tasks\n")
 		}
-		src, found, err := git.ReadFile(p.RepoPath, p.DefaultBranch, todo.File)
+		src, found, err := git.ReadFile(ctx, p.RepoPath, p.DefaultBranch, todo.File)
 		if err != nil {
 			return "", err
 		}
diff --git a/internal/agents/maincommit.go b/internal/agents/maincommit.go
index a1f7e98..8a3907e 100644
--- a/internal/agents/maincommit.go
+++ b/internal/agents/maincommit.go
@@ -15,7 +15,7 @@ func (m *Manager) prepareMainCommit(ctx context.Context, task api.Task, project
 		return "", "", err
 	}
 	env := git.IdentityEnv(user.GitName, user.GitEmail)
-	commit, err := git.SquashCommit(project.RepoPath, task.WorktreePath, project.DefaultBranch, squashMessage(task.MergeTitle, coAuthors), env, m.signer(ctx, user))
+	commit, err := git.SquashCommit(ctx, project.RepoPath, task.WorktreePath, project.DefaultBranch, squashMessage(task.MergeTitle, coAuthors), env, m.signer(ctx, user))
 	if err != nil || commit == "" {
 		return "", "", err
 	}
@@ -23,17 +23,17 @@ func (m *Manager) prepareMainCommit(ctx context.Context, task api.Task, project
 	if err != nil {
 		return "", "", err
 	}
-	notes, err := git.NoteCommit(project.RepoPath, commit, note, env)
+	notes, err := git.NoteCommit(ctx, project.RepoPath, commit, note, env)
 	return commit, notes, err
 }
 
 func advanceMainCheckout(project api.Project, commit, notes string) error {
 	pushed := git.Remote + "/" + project.DefaultBranch
-	err := git.AdvanceNotes(project.RepoPath, notes)
+	err := git.AdvanceNotes(context.Background(), project.RepoPath, notes)
 	if err != nil {
 		return fmt.Errorf("pushed %s to %s, but updating %s in the project checkout failed: %w", commit, pushed, git.NotesRef, err)
 	}
-	err = git.FastForward(project.RepoPath, commit)
+	err = git.FastForward(context.Background(), project.RepoPath, commit)
 	if err != nil {
 		return fmt.Errorf("pushed %s to %s, but fast-forwarding the project checkout failed: %w", commit, pushed, err)
 	}
diff --git a/internal/agents/manager.go b/internal/agents/manager.go
index bf67e65..42e4fa6 100644
--- a/internal/agents/manager.go
+++ b/internal/agents/manager.go
@@ -722,7 +722,7 @@ func (m *Manager) recordMessage(ctx context.Context, sess api.AgentSession, task
 
 	payload := map[string]any{"text": text}
 	if implementer {
-		head, err := git.Head(task.WorktreePath)
+		head, err := git.Head(ctx, task.WorktreePath)
 		if err != nil {
 			return nil, false, err
 		}
@@ -1190,7 +1190,7 @@ func (m *Manager) turnEnded(ctx context.Context, l *live, res endResult) error {
 		return err
 	}
 	if (owner || landingBy != "") && !finished {
-		err := git.AbortMerge(l.dir)
+		err := git.AbortMerge(ctx, l.dir)
 		if err != nil {
 			slog.Error("abort unfinished merge", "session", l.id, "err", err)
 		}
@@ -1209,13 +1209,13 @@ func (m *Manager) turnEnded(ctx context.Context, l *live, res endResult) error {
 			return nil
 		}
 	}
-	sha, err := git.CommitAll(l.dir, commitMessage(res), l.gitName, l.gitEmail)
+	sha, err := git.CommitAll(ctx, l.dir, commitMessage(res), l.gitName, l.gitEmail)
 	if err != nil {
 		slog.Error("commit turn", "session", l.id, "err", err)
 		m.recordError(l, fmt.Sprintf("byre couldn't commit the turn's work, so the turn counts as unfinished: %v", err))
 		finished = false
 		if owner {
-			err = git.AbortMerge(l.dir)
+			err = git.AbortMerge(ctx, l.dir)
 			if err != nil {
 				slog.Error("abort unfinished merge", "session", l.id, "err", err)
 			}
diff --git a/internal/agents/mergefacts.go b/internal/agents/mergefacts.go
index 4f34f02..0556f2f 100644
--- a/internal/agents/mergefacts.go
+++ b/internal/agents/mergefacts.go
@@ -123,15 +123,15 @@ func (m *Manager) gitFacts(ctx context.Context, t api.Task, p api.Project) (stor
 	if t.WorktreePath == "" {
 		return g, nil
 	}
-	tree, err := git.Snapshot(t.WorktreePath)
+	tree, err := git.Snapshot(ctx, t.WorktreePath)
 	if err != nil {
 		return g, err
 	}
-	g.UnmergedCommits, err = git.Ahead(t.WorktreePath, p.DefaultBranch)
+	g.UnmergedCommits, err = git.Ahead(ctx, t.WorktreePath, p.DefaultBranch)
 	if err != nil {
 		return g, err
 	}
-	g.UnmergedFiles, err = git.ChangedFileCount(t.WorktreePath, p.DefaultBranch, tree)
+	g.UnmergedFiles, err = git.ChangedFileCount(ctx, t.WorktreePath, p.DefaultBranch, tree)
 	if err != nil {
 		return g, err
 	}
diff --git a/internal/agents/mergein.go b/internal/agents/mergein.go
index a6db30d..b1f280c 100644
--- a/internal/agents/mergein.go
+++ b/internal/agents/mergein.go
@@ -223,7 +223,7 @@ func pushLanded(ctx context.Context, project api.Project, commit string) (bool,
 	if err != nil {
 		return false, &unfinishedMergeError{fmt.Errorf("checking whether %s reached %s failed: %w", commit, target, err)}
 	}
-	landed, err := git.IsAncestor(project.RepoPath, commit, target)
+	landed, err := git.IsAncestor(ctx, project.RepoPath, commit, target)
 	if err != nil {
 		return false, &unfinishedMergeError{fmt.Errorf("checking whether %s reached %s failed: %w", commit, target, err)}
 	}
@@ -405,7 +405,7 @@ func (m *Manager) RemoveTask(ctx context.Context, task api.Task, project api.Pro
 	if err != nil {
 		return err
 	}
-	return git.RemoveWorktree(project.RepoPath, task.WorktreePath, task.Branch)
+	return git.RemoveWorktree(ctx, project.RepoPath, task.WorktreePath, task.Branch)
 }
 
 type setTitlesArgs struct {
diff --git a/internal/agents/mergemain.go b/internal/agents/mergemain.go
index 8f95001..523e127 100644
--- a/internal/agents/mergemain.go
+++ b/internal/agents/mergemain.go
@@ -115,7 +115,7 @@ func (m *Manager) pushToMain(ctx context.Context, l *live, task api.Task, projec
 	if err != nil {
 		return "", err
 	}
-	_, err = git.CommitAll(l.dir, title, l.gitName, l.gitEmail)
+	_, err = git.CommitAll(ctx, l.dir, title, l.gitName, l.gitEmail)
 	if err != nil {
 		return "", err
 	}
@@ -130,7 +130,7 @@ func (m *Manager) pushToMain(ctx context.Context, l *live, task api.Task, projec
 		return "", err
 	}
 	if commit == "" {
-		err = git.Merge(l.dir, project.DefaultBranch, "Merge "+project.DefaultBranch, l.gitName, l.gitEmail)
+		err = git.Merge(ctx, l.dir, project.DefaultBranch, "Merge "+project.DefaultBranch, l.gitName, l.gitEmail)
 		return "", err
 	}
 
@@ -147,7 +147,7 @@ func (m *Manager) pushToMain(ctx context.Context, l *live, task api.Task, projec
 	if err != nil {
 		return "", err
 	}
-	err = git.Merge(l.dir, commit, fmt.Sprintf("Merge %s from %s", commit[:7], project.DefaultBranch), l.gitName, l.gitEmail)
+	err = git.Merge(ctx, l.dir, commit, fmt.Sprintf("Merge %s from %s", commit[:7], project.DefaultBranch), l.gitName, l.gitEmail)
 	if err != nil {
 		return "", fmt.Errorf("pushed %s to %s, but merging it back into this branch failed: %w", commit, pushed, err)
 	}
diff --git a/internal/agents/review.go b/internal/agents/review.go
index 866ae75..a69e6dd 100644
--- a/internal/agents/review.go
+++ b/internal/agents/review.go
@@ -119,7 +119,7 @@ func (m *Manager) beginReviews(ctx context.Context, ref store.SnapshotRef) error
 	if project.ReviewWorkflow == "" {
 		return finished(api.ReviewStateFailed, "", fmt.Sprintf("project %s has no review workflow", project.Name))
 	}
-	changes, err := git.Compare(project.RepoPath, project.DefaultBranch, snap.CommitSha, snap.TreeSha, "")
+	changes, err := git.Compare(ctx, project.RepoPath, project.DefaultBranch, snap.CommitSha, snap.TreeSha, "")
 	if err != nil {
 		return finished(api.ReviewStateFailed, project.ReviewWorkflow, fmt.Sprintf("byre couldn't compare snapshot %d with %s: %v", snap.N, project.DefaultBranch, err))
 	}
@@ -213,7 +213,7 @@ func (m *Manager) startReviewers(ctx context.Context, task api.Task, project api
 
 func (m *Manager) launchReviewer(ctx context.Context, task api.Task, project api.Project, snap api.Snapshot, rv store.Reviewer, prompt string) {
 	r := rv.Review
-	err := git.AddDetachedWorktree(project.RepoPath, m.reviewDir(project.Id, r.Id), snap.CommitSha)
+	err := git.AddDetachedWorktree(ctx, project.RepoPath, m.reviewDir(project.Id, r.Id), snap.CommitSha)
 	if err == nil {
 		err = os.MkdirAll(m.reviewMediaDir(project.Id, r.Id), 0o755)
 	}
@@ -230,7 +230,7 @@ func (m *Manager) launchReviewer(ctx context.Context, task api.Task, project api
 }
 
 func (m *Manager) reviewPrompt(ctx context.Context, task api.Task, project api.Project, snap api.Snapshot, def api.WorkflowDefinition, stage string, inputs []api.Review) (string, error) {
-	changes, err := git.Compare(project.RepoPath, project.DefaultBranch, snap.CommitSha, snap.TreeSha, "")
+	changes, err := git.Compare(ctx, project.RepoPath, project.DefaultBranch, snap.CommitSha, snap.TreeSha, "")
 	if err != nil {
 		return "", err
 	}
@@ -600,7 +600,7 @@ func (m *Manager) cleanUpReviewer(r store.EndedReviewer) {
 }
 
 func (m *Manager) removeReviewDir(project api.Project, reviewID string) {
-	err := git.RemoveDetachedWorktree(project.RepoPath, m.reviewDir(project.Id, reviewID))
+	err := git.RemoveDetachedWorktree(context.Background(), project.RepoPath, m.reviewDir(project.Id, reviewID))
 	if err != nil {
 		slog.Error("remove review worktree", "review", reviewID, "err", err)
 	}
diff --git a/internal/agents/snapshots.go b/internal/agents/snapshots.go
index 0f5e880..87e9bc9 100644
--- a/internal/agents/snapshots.go
+++ b/internal/agents/snapshots.go
@@ -134,7 +134,7 @@ func (m *Manager) takeSnapshot(ctx context.Context, t snapTarget, trigger api.Sn
 		}
 	}
 
-	tree, err := git.Snapshot(t.dir)
+	tree, err := git.Snapshot(ctx, t.dir)
 	if err != nil {
 		return nil, err
 	}
@@ -152,7 +152,7 @@ func (m *Manager) takeSnapshot(ctx context.Context, t snapTarget, trigger api.Sn
 	}
 
 	n := last.N + 1
-	commit, err := git.CommitSnapshot(t.dir, tree, git.SnapshotRef(t.taskID, n), fmt.Sprintf("byre snapshot %d (%s)", n, trigger), git.IdentityEnv(t.gitName, t.gitEmail))
+	commit, err := git.CommitSnapshot(ctx, t.dir, tree, git.SnapshotRef(t.taskID, n), fmt.Sprintf("byre snapshot %d (%s)", n, trigger), git.IdentityEnv(t.gitName, t.gitEmail))
 	if err != nil {
 		return nil, err
 	}
@@ -279,7 +279,7 @@ func (m *Manager) dropSnapshots(repo, taskID string) error {
 
 	st.mu.Lock()
 	defer st.mu.Unlock()
-	return git.DeleteSnapshotRefs(repo, taskID)
+	return git.DeleteSnapshotRefs(context.Background(), repo, taskID)
 }
 
 func (m *Manager) afterTool(l *live) claude.HookFunc {
diff --git a/internal/agents/subtasks.go b/internal/agents/subtasks.go
index 3694780..fab29c8 100644
--- a/internal/agents/subtasks.go
+++ b/internal/agents/subtasks.go
@@ -65,7 +65,7 @@ func (m *Manager) subtaskTools(l *live) []mcp.Tool {
 				if err != nil {
 					return "", err
 				}
-				base, err := git.Head(l.dir)
+				base, err := git.Head(ctx, l.dir)
 				if err != nil {
 					return "", err
 				}
@@ -372,7 +372,7 @@ func (m *Manager) closeMergedSubtask(ctx context.Context, t api.Task, parentID,
 	if err != nil || t.Status != api.TaskStatusActive {
 		return err
 	}
-	merged, err := git.IsAncestor(dir, t.Branch, "HEAD")
+	merged, err := git.IsAncestor(ctx, dir, t.Branch, "HEAD")
 	if err != nil || !merged {
 		return err
 	}
@@ -384,7 +384,7 @@ func (m *Manager) closeMergedSubtask(ctx context.Context, t api.Task, parentID,
 	if err != nil {
 		return err
 	}
-	head, err := git.Head(dir)
+	head, err := git.Head(ctx, dir)
 	if err != nil {
 		return err
 	}
diff --git a/internal/agents/tasks.go b/internal/agents/tasks.go
index 2d0c449..ba8610e 100644
--- a/internal/agents/tasks.go
+++ b/internal/agents/tasks.go
@@ -52,7 +52,7 @@ func (m *Manager) StartTodo(ctx context.Context, project api.Project, creator ap
 	if creator.GitName == "" || creator.GitEmail == "" {
 		return nil, ErrNoGitIdentity
 	}
-	src, found, err := git.ReadFile(project.RepoPath, project.DefaultBranch, todo.File)
+	src, found, err := git.ReadFile(ctx, project.RepoPath, project.DefaultBranch, todo.File)
 	if err != nil {
 		return nil, err
 	}
@@ -120,14 +120,14 @@ func (m *Manager) createTask(ctx context.Context, project api.Project, t api.Tas
 	t.CreatedAt = time.Now().UTC()
 
 	var err error
-	t.BaseRef, err = git.AddWorktree(project.RepoPath, t.WorktreePath, t.Branch, base)
+	t.BaseRef, err = git.AddWorktree(ctx, project.RepoPath, t.WorktreePath, t.Branch, base)
 	if err != nil {
 		return api.Task{}, err
 	}
 
 	err = m.store.CreateTask(ctx, t, nil, actor)
 	if err != nil {
-		rerr := git.RemoveWorktree(project.RepoPath, t.WorktreePath, t.Branch)
+		rerr := git.RemoveWorktree(ctx, project.RepoPath, t.WorktreePath, t.Branch)
 		if rerr != nil {
 			slog.Error("remove worktree of task not created", "task", t.Id, "err", rerr)
 		}
diff --git a/internal/agents/workflows.go b/internal/agents/workflows.go
index ce9278e..1a77b3e 100644
--- a/internal/agents/workflows.go
+++ b/internal/agents/workflows.go
@@ -355,7 +355,7 @@ func (m *Manager) recordStage(ctx context.Context, l *live) error {
 	if err != nil {
 		return err
 	}
-	head, err := git.Head(l.dir)
+	head, err := git.Head(ctx, l.dir)
 	if err != nil {
 		return err
 	}
@@ -411,7 +411,7 @@ func (m *Manager) nextStage(ctx context.Context, sessionID string) ([]string, er
 		return nil, err
 	}
 	if recorded == "" {
-		head, err := git.Head(task.WorktreePath)
+		head, err := git.Head(ctx, task.WorktreePath)
 		if err != nil {
 			return nil, err
 		}
diff --git a/internal/git/changes.go b/internal/git/changes.go
index 600065b..61669e1 100644
--- a/internal/git/changes.go
+++ b/internal/git/changes.go
@@ -1,6 +1,7 @@
 package git
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"strconv"
@@ -17,25 +18,25 @@ var statuses = map[byte]api.FileChangeStatus{
 	'T': api.TypeChanged,
 }
 
-func Changes(dir, defaultBranch, since string) (api.TaskChanges, error) {
-	tree, err := Snapshot(dir)
+func Changes(ctx context.Context, dir, defaultBranch, since string) (api.TaskChanges, error) {
+	tree, err := Snapshot(ctx, dir)
 	if err != nil {
 		return api.TaskChanges{}, err
 	}
-	return Compare(dir, defaultBranch, "HEAD", tree, since)
+	return Compare(ctx, dir, defaultBranch, "HEAD", tree, since)
 }
 
-func Compare(dir, defaultBranch, head, tree, since string) (api.TaskChanges, error) {
+func Compare(ctx context.Context, dir, defaultBranch, head, tree, since string) (api.TaskChanges, error) {
 	base := since
 	if base == "" {
-		mb, err := run(dir, "merge-base", head, defaultBranch)
+		mb, err := run(ctx, dir, "merge-base", head, defaultBranch)
 		if err != nil {
 			return api.TaskChanges{}, err
 		}
 		base = mb
 	}
 
-	files, err := stats(dir, base, tree)
+	files, err := stats(ctx, dir, base, tree)
 	if err != nil {
 		return api.TaskChanges{}, err
 	}
@@ -43,20 +44,20 @@ func Compare(dir, defaultBranch, head, tree, since string) (api.TaskChanges, err
 	return api.TaskChanges{Base: base, Tree: tree, Files: files}, nil
 }
 
-func ChangedFileCount(dir, defaultBranch, tree string) (int, error) {
-	base, err := run(dir, "merge-base", "HEAD", defaultBranch)
+func ChangedFileCount(ctx context.Context, dir, defaultBranch, tree string) (int, error) {
+	base, err := run(ctx, dir, "merge-base", "HEAD", defaultBranch)
 	if err != nil {
 		return 0, err
 	}
-	paths, err := run(dir, "diff", "--find-renames", "--name-only", "-z", base, tree)
+	paths, err := run(ctx, dir, "diff", "--find-renames", "--name-only", "-z", base, tree)
 	if err != nil {
 		return 0, err
 	}
 	return strings.Count(paths, "\x00"), nil
 }
 
-func Snapshot(dir string) (string, error) {
-	index, err := run(dir, "rev-parse", "--path-format=absolute", "--git-path", "index")
+func Snapshot(ctx context.Context, dir string) (string, error) {
+	index, err := run(ctx, dir, "rev-parse", "--path-format=absolute", "--git-path", "index")
 	if err != nil {
 		return "", err
 	}
@@ -90,27 +91,27 @@ func Snapshot(dir string) (string, error) {
 	}
 
 	env := []string{"GIT_INDEX_FILE=" + tmp.Name()}
-	_, err = runEnv(dir, env, "add", "--all")
+	_, err = runEnv(ctx, dir, env, "add", "--all")
 	if err != nil {
 		return "", err
 	}
-	return runEnv(dir, env, "write-tree")
+	return runEnv(ctx, dir, env, "write-tree")
 }
 
-func FileDiff(dir, base, tree, path, oldPath string) (string, error) {
+func FileDiff(ctx context.Context, dir, base, tree, path, oldPath string) (string, error) {
 	args := []string{"diff", "--find-renames", "--no-ext-diff", "--no-color", base, tree, "--", path}
 	if oldPath != "" {
 		args = append(args, oldPath)
 	}
-	return run(dir, args...)
+	return run(ctx, dir, args...)
 }
 
-func stats(dir, base, tree string) ([]api.FileChange, error) {
-	nameStatus, err := run(dir, "diff", "--find-renames", "--name-status", "-z", base, tree)
+func stats(ctx context.Context, dir, base, tree string) ([]api.FileChange, error) {
+	nameStatus, err := run(ctx, dir, "diff", "--find-renames", "--name-status", "-z", base, tree)
 	if err != nil {
 		return nil, err
 	}
-	numstat, err := run(dir, "diff", "--find-renames", "--numstat", "-z", base, tree)
+	numstat, err := run(ctx, dir, "diff", "--find-renames", "--numstat", "-z", base, tree)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/git/git.go b/internal/git/git.go
index ca84b2f..c5e96f8 100644
--- a/internal/git/git.go
+++ b/internal/git/git.go
@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"g.fc.run/ai/byre/internal/procgroup"
+	"g.fc.run/ai/byre/internal/trace"
 )
 
 type RepoInfo struct {
@@ -22,13 +23,13 @@ type RepoInfo struct {
 	Remote        string
 }
 
-func Inspect(path string) (RepoInfo, error) {
+func Inspect(ctx context.Context, path string) (RepoInfo, error) {
 	abs, err := filepath.Abs(path)
 	if err != nil {
 		return RepoInfo{}, err
 	}
 
-	root, err := run(abs, "rev-parse", "--show-toplevel")
+	root, err := run(ctx, abs, "rev-parse", "--show-toplevel")
 	if err != nil {
 		return RepoInfo{}, err
 	}
@@ -47,12 +48,12 @@ func Inspect(path string) (RepoInfo, error) {
 		return RepoInfo{}, fmt.Errorf("%s is inside the repo at %s; register the repo root", abs, root)
 	}
 
-	branch, err := run(root, "symbolic-ref", "--short", "HEAD")
+	branch, err := run(ctx, root, "symbolic-ref", "--short", "HEAD")
 	if err != nil {
 		return RepoInfo{}, err
 	}
 
-	remote, err := run(root, "remote", "get-url", "origin")
+	remote, err := run(ctx, root, "remote", "get-url", "origin")
 	if err != nil {
 		return RepoInfo{}, err
 	}
@@ -60,13 +61,13 @@ func Inspect(path string) (RepoInfo, error) {
 	return RepoInfo{Root: root, DefaultBranch: branch, Remote: remote}, nil
 }
 
-func AddWorktree(repo, path, branch, base string) (string, error) {
-	sha, err := run(repo, "rev-parse", "--verify", base+"^{commit}")
+func AddWorktree(ctx context.Context, repo, path, branch, base string) (string, error) {
+	sha, err := run(ctx, repo, "rev-parse", "--verify", base+"^{commit}")
 	if err != nil {
 		return "", err
 	}
 
-	_, err = run(repo, "worktree", "add", "-b", branch, path, sha)
+	_, err = run(ctx, repo, "worktree", "add", "-b", branch, path, sha)
 	if err != nil {
 		return "", err
 	}
@@ -74,38 +75,38 @@ func AddWorktree(repo, path, branch, base string) (string, error) {
 	return sha, nil
 }
 
-func AddDetachedWorktree(repo, path, commit string) error {
-	_, err := run(repo, "worktree", "add", "--detach", path, commit)
+func AddDetachedWorktree(ctx context.Context, repo, path, commit string) error {
+	_, err := run(ctx, repo, "worktree", "add", "--detach", path, commit)
 	return err
 }
 
-func RemoveDetachedWorktree(repo, path string) error {
+func RemoveDetachedWorktree(ctx context.Context, repo, path string) error {
 	_, err := os.Stat(path)
 	if errors.Is(err, os.ErrNotExist) {
 		return nil
 	}
-	_, err = run(repo, "worktree", "remove", "--force", path)
+	_, err = run(ctx, repo, "worktree", "remove", "--force", path)
 	return err
 }
 
-func RemoveWorktree(repo, path, branch string) error {
-	list, err := run(repo, "worktree", "list", "--porcelain")
+func RemoveWorktree(ctx context.Context, repo, path, branch string) error {
+	list, err := run(ctx, repo, "worktree", "list", "--porcelain")
 	if err != nil {
 		return err
 	}
 	_, statErr := os.Stat(path)
 	if statErr == nil || slices.Contains(strings.Split(list, "\n"), "worktree "+path) {
-		_, err = run(repo, "worktree", "remove", "--force", path)
+		_, err = run(ctx, repo, "worktree", "remove", "--force", path)
 		if err != nil {
 			return err
 		}
 	}
 
-	_, _, code, err := runCode(repo, nil, "rev-parse", "--verify", "--quiet", "refs/heads/"+branch)
+	_, _, code, err := runCode(ctx, repo, nil, "rev-parse", "--verify", "--quiet", "refs/heads/"+branch)
 	if err != nil || code != 0 {
 		return err
 	}
-	_, err = run(repo, "branch", "-D", branch)
+	_, err = run(ctx, repo, "branch", "-D", branch)
 	return err
 }
 
@@ -117,24 +118,24 @@ func (e *ConflictError) Error() string {
 	return "merge conflicts in " + strings.Join(e.Files, ", ")
 }
 
-func Ahead(worktree, target string) (int, error) {
-	count, err := run(worktree, "rev-list", "--count", target+"..HEAD")
+func Ahead(ctx context.Context, worktree, target string) (int, error) {
+	count, err := run(ctx, worktree, "rev-list", "--count", target+"..HEAD")
 	if err != nil {
 		return 0, err
 	}
 	return strconv.Atoi(count)
 }
 
-func Behind(worktree, target string) (int, error) {
-	count, err := run(worktree, "rev-list", "--count", "HEAD.."+target)
+func Behind(ctx context.Context, worktree, target string) (int, error) {
+	count, err := run(ctx, worktree, "rev-list", "--count", "HEAD.."+target)
 	if err != nil {
 		return 0, err
 	}
 	return strconv.Atoi(count)
 }
 
-func SquashCommit(repo, worktree, target, message string, env []string, sign func(payload []byte) ([]byte, error)) (string, error) {
-	checkedOut, err := run(repo, "symbolic-ref", "--short", "HEAD")
+func SquashCommit(ctx context.Context, repo, worktree, target, message string, env []string, sign func(payload []byte) ([]byte, error)) (string, error) {
+	checkedOut, err := run(ctx, repo, "symbolic-ref", "--short", "HEAD")
 	if err != nil {
 		return "", err
 	}
@@ -142,20 +143,20 @@ func SquashCommit(repo, worktree, target, message string, env []string, sign fun
 		return "", fmt.Errorf("%s has %s checked out, not %s", repo, checkedOut, target)
 	}
 
-	tree, err := Snapshot(worktree)
+	tree, err := Snapshot(ctx, worktree)
 	if err != nil {
 		return "", err
 	}
-	base, err := run(worktree, "merge-base", target, "HEAD")
+	base, err := run(ctx, worktree, "merge-base", target, "HEAD")
 	if err != nil {
 		return "", err
 	}
-	head, err := run(repo, "rev-parse", target)
+	head, err := run(ctx, repo, "rev-parse", target)
 	if err != nil {
 		return "", err
 	}
 
-	out, stderr, code, err := runCode(repo, nil, "merge-tree", "--write-tree", "--name-only", "--merge-base="+base, head, tree)
+	out, stderr, code, err := runCode(ctx, repo, nil, "merge-tree", "--write-tree", "--name-only", "--merge-base="+base, head, tree)
 	if err != nil {
 		return "", err
 	}
@@ -174,7 +175,7 @@ func SquashCommit(repo, worktree, target, message string, env []string, sign fun
 		return "", fmt.Errorf("git merge-tree exited %d: %s", code, stderr)
 	}
 
-	headTree, err := run(repo, "rev-parse", head+"^{tree}")
+	headTree, err := run(ctx, repo, "rev-parse", head+"^{tree}")
 	if err != nil {
 		return "", err
 	}
@@ -182,11 +183,11 @@ func SquashCommit(repo, worktree, target, message string, env []string, sign fun
 		return "", nil
 	}
 
-	commit, err := runEnv(repo, env, "commit-tree", lines[0], "-p", head, "-m", message)
+	commit, err := runEnv(ctx, repo, env, "commit-tree", lines[0], "-p", head, "-m", message)
 	if err != nil {
 		return "", err
 	}
-	signing, stderr, code, err := runCode(repo, nil, "config", "--type=bool", "--get", "commit.gpgsign")
+	signing, stderr, code, err := runCode(ctx, repo, nil, "config", "--type=bool", "--get", "commit.gpgsign")
 	if err != nil {
 		return "", err
 	}
@@ -196,11 +197,11 @@ func SquashCommit(repo, worktree, target, message string, env []string, sign fun
 	if signing != "true" {
 		return commit, nil
 	}
-	return signCommit(repo, commit, sign)
+	return signCommit(ctx, repo, commit, sign)
 }
 
-func signCommit(repo, commit string, sign func(payload []byte) ([]byte, error)) (string, error) {
-	payload, err := runRaw(repo, nil, "", "cat-file", "commit", commit)
+func signCommit(ctx context.Context, repo, commit string, sign func(payload []byte) ([]byte, error)) (string, error) {
+	payload, err := runRaw(ctx, repo, nil, "", "cat-file", "commit", commit)
 	if err != nil {
 		return "", err
 	}
@@ -214,7 +215,7 @@ func signCommit(repo, commit string, sign func(payload []byte) ([]byte, error))
 	}
 	header := "gpgsig " + strings.ReplaceAll(strings.TrimSuffix(string(sig), "\n"), "\n", "\n ") + "\n"
 	signed := payload[:eoh+1] + header + payload[eoh+1:]
-	return runInput(repo, nil, signed, "hash-object", "-t", "commit", "-w", "--stdin")
+	return runInput(ctx, repo, nil, signed, "hash-object", "-t", "commit", "-w", "--stdin")
 }
 
 const Remote = "origin"
@@ -244,8 +245,8 @@ func Push(ctx context.Context, repo, commit, branch, notes string) error {
 	return fmt.Errorf("pushing %s to %s: exit status %d: %s", branch, Remote, code, strings.TrimSpace(out+"\n"+stderr))
 }
 
-func FastForward(repo, rev string) error {
-	_, err := run(repo, "merge", "--ff-only", rev)
+func FastForward(ctx context.Context, repo, rev string) error {
+	_, err := run(ctx, repo, "merge", "--ff-only", rev)
 	return err
 }
 
@@ -265,19 +266,19 @@ func FetchFastForward(ctx context.Context, repo, branch string) error {
 	if err != nil {
 		return err
 	}
-	return FastForward(repo, Remote+"/"+branch)
+	return FastForward(ctx, repo, Remote+"/"+branch)
 }
 
-func Head(dir string) (string, error) {
-	return run(dir, "rev-parse", "HEAD")
+func Head(ctx context.Context, dir string) (string, error) {
+	return run(ctx, dir, "rev-parse", "HEAD")
 }
 
-func BranchHead(repo, branch string) (string, error) {
-	return run(repo, "rev-parse", "--verify", "refs/heads/"+branch+"^{commit}")
+func BranchHead(ctx context.Context, repo, branch string) (string, error) {
+	return run(ctx, repo, "rev-parse", "--verify", "refs/heads/"+branch+"^{commit}")
 }
 
-func IsAncestor(dir, ancestor, descendant string) (bool, error) {
-	_, stderr, code, err := runCode(dir, nil, "merge-base", "--is-ancestor", ancestor, descendant)
+func IsAncestor(ctx context.Context, dir, ancestor, descendant string) (bool, error) {
+	_, stderr, code, err := runCode(ctx, dir, nil, "merge-base", "--is-ancestor", ancestor, descendant)
 	if err != nil {
 		return false, err
 	}
@@ -290,38 +291,38 @@ func IsAncestor(dir, ancestor, descendant string) (bool, error) {
 	return false, fmt.Errorf("git merge-base --is-ancestor %s %s: exit status %d: %s", ancestor, descendant, code, stderr)
 }
 
-func MergeInProgress(dir string) (bool, error) {
-	_, _, code, err := runCode(dir, nil, "rev-parse", "--quiet", "--verify", "MERGE_HEAD")
+func MergeInProgress(ctx context.Context, dir string) (bool, error) {
+	_, _, code, err := runCode(ctx, dir, nil, "rev-parse", "--quiet", "--verify", "MERGE_HEAD")
 	return err == nil && code == 0, err
 }
 
-func AbortMerge(dir string) error {
-	merging, err := MergeInProgress(dir)
+func AbortMerge(ctx context.Context, dir string) error {
+	merging, err := MergeInProgress(ctx, dir)
 	if err != nil || !merging {
 		return err
 	}
-	_, err = run(dir, "merge", "--abort")
+	_, err = run(ctx, dir, "merge", "--abort")
 	return err
 }
 
-func ReadFile(repo, rev, path string) (string, bool, error) {
-	_, _, code, err := runCode(repo, nil, "cat-file", "-e", rev+":"+path)
+func ReadFile(ctx context.Context, repo, rev, path string) (string, bool, error) {
+	_, _, code, err := runCode(ctx, repo, nil, "cat-file", "-e", rev+":"+path)
 	if err != nil {
 		return "", false, err
 	}
 	if code != 0 {
 		return "", false, nil
 	}
-	out, err := run(repo, "cat-file", "blob", rev+":"+path)
+	out, err := run(ctx, repo, "cat-file", "blob", rev+":"+path)
 	return out, true, err
 }
 
-func CommitAll(dir, message, name, email string) (string, error) {
-	status, err := run(dir, "status", "--porcelain", "--untracked-files=all")
+func CommitAll(ctx context.Context, dir, message, name, email string) (string, error) {
+	status, err := run(ctx, dir, "status", "--porcelain", "--untracked-files=all")
 	if err != nil {
 		return "", err
 	}
-	merging, err := MergeInProgress(dir)
+	merging, err := MergeInProgress(ctx, dir)
 	if err != nil {
 		return "", err
 	}
@@ -330,38 +331,38 @@ func CommitAll(dir, message, name, email string) (string, error) {
 	}
 
 	env := IdentityEnv(name, email)
-	_, err = runEnv(dir, env, "add", "--all")
+	_, err = runEnv(ctx, dir, env, "add", "--all")
 	if err != nil {
 		return "", err
 	}
-	_, err = runEnv(dir, env, "commit", "--quiet", "--message", message)
+	_, err = runEnv(ctx, dir, env, "commit", "--quiet", "--message", message)
 	if err != nil {
 		return "", err
 	}
-	return Head(dir)
+	return Head(ctx, dir)
 }
 
-func Merge(dir, rev, message, name, email string) error {
+func Merge(ctx context.Context, dir, rev, message, name, email string) error {
 	env := IdentityEnv(name, email)
-	_, err := runEnv(dir, env, "merge", "--no-ff", "--quiet", "--message", message, rev)
+	_, err := runEnv(ctx, dir, env, "merge", "--no-ff", "--quiet", "--message", message, rev)
 	return err
 }
 
-func run(dir string, args ...string) (string, error) {
-	return runEnv(dir, nil, args...)
+func run(ctx context.Context, dir string, args ...string) (string, error) {
+	return runEnv(ctx, dir, nil, args...)
 }
 
-func runEnv(dir string, env []string, args ...string) (string, error) {
-	return runInput(dir, env, "", args...)
+func runEnv(ctx context.Context, dir string, env []string, args ...string) (string, error) {
+	return runInput(ctx, dir, env, "", args...)
 }
 
-func runInput(dir string, env []string, input string, args ...string) (string, error) {
-	out, err := runRaw(dir, env, input, args...)
+func runInput(ctx context.Context, dir string, env []string, input string, args ...string) (string, error) {
+	out, err := runRaw(ctx, dir, env, input, args...)
 	return strings.TrimSpace(out), err
 }
 
-func runRaw(dir string, env []string, input string, args ...string) (string, error) {
-	out, stderr, code, err := runCodeInput(context.Background(), dir, env, strings.NewReader(input), args...)
+func runRaw(ctx context.Context, dir string, env []string, input string, args ...string) (string, error) {
+	out, stderr, code, err := runCodeInput(context.WithoutCancel(ctx), dir, env, strings.NewReader(input), args...)
 	if err != nil {
 		return "", err
 	}
@@ -371,8 +372,8 @@ func runRaw(dir string, env []string, input string, args ...string) (string, err
 	return out, nil
 }
 
-func runCode(dir string, env []string, args ...string) (string, string, int, error) {
-	out, stderr, code, err := runCodeInput(context.Background(), dir, env, nil, args...)
+func runCode(ctx context.Context, dir string, env []string, args ...string) (string, string, int, error) {
+	out, stderr, code, err := runCodeInput(context.WithoutCancel(ctx), dir, env, nil, args...)
 	return strings.TrimSpace(out), stderr, code, err
 }
 
@@ -384,6 +385,7 @@ func runNetwork(ctx context.Context, dir string, args ...string) (string, string
 }
 
 func runCodeInput(ctx context.Context, dir string, env []string, stdin io.Reader, args ...string) (string, string, int, error) {
+	defer trace.Start(ctx, "git "+args[0])()
 	argv := args
 	if args[0] != "config" {
 		argv = append([]string{"-c", "commit.gpgsign=false"}, args...)
diff --git a/internal/git/ignore.go b/internal/git/ignore.go
index 549019b..6ae99d3 100644
--- a/internal/git/ignore.go
+++ b/internal/git/ignore.go
@@ -6,13 +6,13 @@ import (
 	"strings"
 )
 
-func Ignored(worktree string, paths []string) (map[string]bool, error) {
+func Ignored(ctx context.Context, worktree string, paths []string) (map[string]bool, error) {
 	ignored := map[string]bool{}
 	if len(paths) == 0 {
 		return ignored, nil
 	}
 
-	out, stderr, code, err := runCodeInput(context.Background(), worktree, nil, strings.NewReader(strings.Join(paths, "\x00")+"\x00"), "check-ignore", "--stdin", "-z")
+	out, stderr, code, err := runCodeInput(context.WithoutCancel(ctx), worktree, nil, strings.NewReader(strings.Join(paths, "\x00")+"\x00"), "check-ignore", "--stdin", "-z")
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/git/notes.go b/internal/git/notes.go
index d2e1ae1..8077d94 100644
--- a/internal/git/notes.go
+++ b/internal/git/notes.go
@@ -1,6 +1,7 @@
 package git
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -12,9 +13,9 @@ const NotesRef = "refs/notes/byre"
 
 const notesFetch = NotesRef + "*:" + NotesRef + "*"
 
-func ConfigureNotesFetch(repo string) error {
+func ConfigureNotesFetch(ctx context.Context, repo string) error {
 	key := "remote." + Remote + ".fetch"
-	out, stderr, code, err := runCode(repo, nil, "config", "--get-all", key)
+	out, stderr, code, err := runCode(ctx, repo, nil, "config", "--get-all", key)
 	if err != nil {
 		return err
 	}
@@ -24,17 +25,17 @@ func ConfigureNotesFetch(repo string) error {
 	if slices.Contains(strings.Split(out, "\n"), notesFetch) {
 		return nil
 	}
-	_, err = run(repo, "config", "--add", key, notesFetch)
+	_, err = run(ctx, repo, "config", "--add", key, notesFetch)
 	return err
 }
 
-func NoteCommit(repo, commit, note string, env []string) (string, error) {
-	blob, err := runInput(repo, nil, note, "hash-object", "-w", "--stdin")
+func NoteCommit(ctx context.Context, repo, commit, note string, env []string) (string, error) {
+	blob, err := runInput(ctx, repo, nil, note, "hash-object", "-w", "--stdin")
 	if err != nil {
 		return "", err
 	}
 
-	parent, stderr, code, err := runCode(repo, nil, "rev-parse", "--verify", "--quiet", NotesRef)
+	parent, stderr, code, err := runCode(ctx, repo, nil, "rev-parse", "--verify", "--quiet", NotesRef)
 	if err != nil {
 		return "", err
 	}
@@ -51,26 +52,26 @@ func NoteCommit(repo, commit, note string, env []string) (string, error) {
 
 	commitArgs := []string{"commit-tree", "-m", "Notes added by byre"}
 	if code == 0 {
-		_, err = runEnv(repo, index, "read-tree", parent)
+		_, err = runEnv(ctx, repo, index, "read-tree", parent)
 		if err != nil {
 			return "", err
 		}
 		commitArgs = append(commitArgs, "-p", parent)
 	}
-	_, err = runEnv(repo, index, "update-index", "--add", "--cacheinfo", "100644,"+blob+","+commit)
+	_, err = runEnv(ctx, repo, index, "update-index", "--add", "--cacheinfo", "100644,"+blob+","+commit)
 	if err != nil {
 		return "", err
 	}
-	tree, err := runEnv(repo, index, "write-tree")
+	tree, err := runEnv(ctx, repo, index, "write-tree")
 	if err != nil {
 		return "", err
 	}
 
-	return runEnv(repo, env, append(commitArgs, tree)...)
+	return runEnv(ctx, repo, env, append(commitArgs, tree)...)
 }
 
-func AdvanceNotes(repo, notes string) error {
-	current, stderr, code, err := runCode(repo, nil, "rev-parse", "--verify", "--quiet", NotesRef)
+func AdvanceNotes(ctx context.Context, repo, notes string) error {
+	current, stderr, code, err := runCode(ctx, repo, nil, "rev-parse", "--verify", "--quiet", NotesRef)
 	if err != nil {
 		return err
 	}
@@ -78,7 +79,7 @@ func AdvanceNotes(repo, notes string) error {
 		return fmt.Errorf("git rev-parse %s: exit status %d: %s", NotesRef, code, stderr)
 	}
 	if code == 0 {
-		contained, err := IsAncestor(repo, notes, current)
+		contained, err := IsAncestor(ctx, repo, notes, current)
 		if err != nil {
 			return err
 		}
@@ -86,6 +87,6 @@ func AdvanceNotes(repo, notes string) error {
 			return nil
 		}
 	}
-	_, err = run(repo, "update-ref", NotesRef, notes)
+	_, err = run(ctx, repo, "update-ref", NotesRef, notes)
 	return err
 }
diff --git a/internal/git/rename.go b/internal/git/rename.go
index 13a84cc..35939c1 100644
--- a/internal/git/rename.go
+++ b/internal/git/rename.go
@@ -2,6 +2,7 @@ package git
 
 import (
 	"bufio"
+	"context"
 	"fmt"
 	"io"
 	"os"
@@ -10,8 +11,8 @@ import (
 	"strings"
 )
 
-func RenameRefs(repo string, rename func(string) string) error {
-	branches, err := run(repo, "for-each-ref", "--format=%(refname:short)", "refs/heads/byre/")
+func RenameRefs(ctx context.Context, repo string, rename func(string) string) error {
+	branches, err := run(ctx, repo, "for-each-ref", "--format=%(refname:short)", "refs/heads/byre/")
 	if err != nil {
 		return err
 	}
@@ -19,13 +20,13 @@ func RenameRefs(repo string, rename func(string) string) error {
 		if rename(b) == b {
 			continue
 		}
-		_, err = run(repo, "branch", "-m", b, rename(b))
+		_, err = run(ctx, repo, "branch", "-m", b, rename(b))
 		if err != nil {
 			return err
 		}
 	}
 
-	snaps, err := run(repo, "for-each-ref", "--format=%(objectname) %(refname)", "refs/byre/tasks/")
+	snaps, err := run(ctx, repo, "for-each-ref", "--format=%(objectname) %(refname)", "refs/byre/tasks/")
 	if err != nil {
 		return err
 	}
@@ -40,20 +41,20 @@ func RenameRefs(repo string, rename func(string) string) error {
 	if b.Len() == 0 {
 		return nil
 	}
-	_, err = runInput(repo, nil, b.String(), "update-ref", "--stdin")
+	_, err = runInput(ctx, repo, nil, b.String(), "update-ref", "--stdin")
 	return err
 }
 
-func RepairWorktrees(repo string, paths []string) error {
+func RepairWorktrees(ctx context.Context, repo string, paths []string) error {
 	if len(paths) == 0 {
 		return nil
 	}
-	_, err := run(repo, append([]string{"worktree", "repair"}, paths...)...)
+	_, err := run(ctx, repo, append([]string{"worktree", "repair"}, paths...)...)
 	return err
 }
 
-func RewriteNotes(repo string, rewrite func(string) string) error {
-	parent, stderr, code, err := runCode(repo, nil, "rev-parse", "--verify", "--quiet", NotesRef)
+func RewriteNotes(ctx context.Context, repo string, rewrite func(string) string) error {
+	parent, stderr, code, err := runCode(ctx, repo, nil, "rev-parse", "--verify", "--quiet", NotesRef)
 	if err != nil {
 		return err
 	}
@@ -64,7 +65,7 @@ func RewriteNotes(repo string, rewrite func(string) string) error {
 		return fmt.Errorf("git rev-parse %s: exit status %d: %s", NotesRef, code, stderr)
 	}
 
-	listing, err := run(repo, "ls-tree", "-r", parent)
+	listing, err := run(ctx, repo, "ls-tree", "-r", parent)
 	if err != nil {
 		return err
 	}
@@ -80,7 +81,7 @@ func RewriteNotes(repo string, rewrite func(string) string) error {
 		return nil
 	}
 
-	contents, err := catBlobs(repo, shas)
+	contents, err := catBlobs(ctx, repo, shas)
 	if err != nil {
 		return err
 	}
@@ -110,12 +111,12 @@ func RewriteNotes(repo string, rewrite func(string) string) error {
 		return nil
 	}
 
-	blobs, err := runInput(repo, nil, strings.Join(files, "\n")+"\n", "hash-object", "-w", "--stdin-paths")
+	blobs, err := runInput(ctx, repo, nil, strings.Join(files, "\n")+"\n", "hash-object", "-w", "--stdin-paths")
 	if err != nil {
 		return err
 	}
 	index := []string{"GIT_INDEX_FILE=" + filepath.Join(dir, "index")}
-	_, err = runEnv(repo, index, "read-tree", parent)
+	_, err = runEnv(ctx, repo, index, "read-tree", parent)
 	if err != nil {
 		return err
 	}
@@ -123,30 +124,30 @@ func RewriteNotes(repo string, rewrite func(string) string) error {
 	for i, blob := range splitLines(blobs) {
 		fmt.Fprintf(b, "100644 %s\t%s\n", blob, paths[changed[i]])
 	}
-	_, err = runInput(repo, index, b.String(), "update-index", "--index-info")
+	_, err = runInput(ctx, repo, index, b.String(), "update-index", "--index-info")
 	if err != nil {
 		return err
 	}
-	tree, err := runEnv(repo, index, "write-tree")
+	tree, err := runEnv(ctx, repo, index, "write-tree")
 	if err != nil {
 		return err
 	}
-	who, err := run(repo, "log", "-1", "--format=%cn%n%ce", parent)
+	who, err := run(ctx, repo, "log", "-1", "--format=%cn%n%ce", parent)
 	if err != nil {
 		return err
 	}
 	name, email, _ := strings.Cut(who, "\n")
 	env := IdentityEnv(name, email)
-	commit, err := runEnv(repo, env, "commit-tree", "-p", parent, "-m", "Rewrite byre ids in notes", tree)
+	commit, err := runEnv(ctx, repo, env, "commit-tree", "-p", parent, "-m", "Rewrite byre ids in notes", tree)
 	if err != nil {
 		return err
 	}
-	_, err = run(repo, "update-ref", NotesRef, commit, parent)
+	_, err = run(ctx, repo, "update-ref", NotesRef, commit, parent)
 	return err
 }
 
-func catBlobs(repo string, shas []string) (map[string]string, error) {
-	out, err := runRaw(repo, nil, strings.Join(shas, "\n")+"\n", "cat-file", "--batch")
+func catBlobs(ctx context.Context, repo string, shas []string) (map[string]string, error) {
+	out, err := runRaw(ctx, repo, nil, strings.Join(shas, "\n")+"\n", "cat-file", "--batch")
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/git/snapshot.go b/internal/git/snapshot.go
index b22b2c5..c7e7f01 100644
--- a/internal/git/snapshot.go
+++ b/internal/git/snapshot.go
@@ -1,6 +1,7 @@
 package git
 
 import (
+	"context"
 	"fmt"
 	"strings"
 )
@@ -13,24 +14,24 @@ func SnapshotRef(taskID string, n int) string {
 	return fmt.Sprintf("%s%d", snapshotPrefix(taskID), n)
 }
 
-func CommitSnapshot(dir, tree, ref, message string, env []string) (string, error) {
-	head, err := Head(dir)
+func CommitSnapshot(ctx context.Context, dir, tree, ref, message string, env []string) (string, error) {
+	head, err := Head(ctx, dir)
 	if err != nil {
 		return "", err
 	}
-	commit, err := runEnv(dir, env, "commit-tree", tree, "-p", head, "-m", message)
+	commit, err := runEnv(ctx, dir, env, "commit-tree", tree, "-p", head, "-m", message)
 	if err != nil {
 		return "", err
 	}
-	_, err = run(dir, "update-ref", ref, commit, "")
+	_, err = run(ctx, dir, "update-ref", ref, commit, "")
 	if err != nil {
 		return "", err
 	}
 	return commit, nil
 }
 
-func SnapshotRefs(repo, taskID string) ([]string, error) {
-	out, err := run(repo, "for-each-ref", "--format=%(refname)", snapshotPrefix(taskID))
+func SnapshotRefs(ctx context.Context, repo, taskID string) ([]string, error) {
+	out, err := run(ctx, repo, "for-each-ref", "--format=%(refname)", snapshotPrefix(taskID))
 	if err != nil {
 		return nil, err
 	}
@@ -40,8 +41,8 @@ func SnapshotRefs(repo, taskID string) ([]string, error) {
 	return strings.Split(out, "\n"), nil
 }
 
-func DeleteSnapshotRefs(repo, taskID string) error {
-	refs, err := SnapshotRefs(repo, taskID)
+func DeleteSnapshotRefs(ctx context.Context, repo, taskID string) error {
+	refs, err := SnapshotRefs(ctx, repo, taskID)
 	if err != nil {
 		return err
 	}
@@ -53,6 +54,6 @@ func DeleteSnapshotRefs(repo, taskID string) error {
 	for _, ref := range refs {
 		fmt.Fprintf(b, "delete %s\n", ref)
 	}
-	_, err = runInput(repo, nil, b.String(), "update-ref", "--stdin")
+	_, err = runInput(ctx, repo, nil, b.String(), "update-ref", "--stdin")
 	return err
 }
diff --git a/internal/server/changes.go b/internal/server/changes.go
index 40f2b37..40a3823 100644
--- a/internal/server/changes.go
+++ b/internal/server/changes.go
@@ -40,7 +40,7 @@ func (s *Server) GetTaskChanges(w http.ResponseWriter, r *http.Request, taskID s
 		}
 	}
 
-	changes, err := git.Changes(t.WorktreePath, p.DefaultBranch, since)
+	changes, err := git.Changes(r.Context(), t.WorktreePath, p.DefaultBranch, since)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, err)
 		return
@@ -64,7 +64,7 @@ func (s *Server) snapshotChanges(w http.ResponseWriter, r *http.Request, t api.T
 		}
 	}
 
-	changes, err := git.Compare(t.WorktreePath, p.DefaultBranch, snap.CommitSha, snap.TreeSha, since)
+	changes, err := git.Compare(r.Context(), t.WorktreePath, p.DefaultBranch, snap.CommitSha, snap.TreeSha, since)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, err)
 		return
@@ -97,7 +97,7 @@ func (s *Server) GetTaskDiff(w http.ResponseWriter, r *http.Request, taskID stri
 	if params.OldPath != nil {
 		oldPath = *params.OldPath
 	}
-	patch, err := git.FileDiff(t.WorktreePath, params.Base, params.Tree, params.Path, oldPath)
+	patch, err := git.FileDiff(r.Context(), t.WorktreePath, params.Base, params.Tree, params.Path, oldPath)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, err)
 		return
diff --git a/internal/server/files.go b/internal/server/files.go
index 18b83a1..7c079fe 100644
--- a/internal/server/files.go
+++ b/internal/server/files.go
@@ -102,7 +102,7 @@ func (s *Server) GetTaskDir(w http.ResponseWriter, r *http.Request, taskID strin
 	for _, e := range listing.Entries {
 		paths = append(paths, path.Join(real, e.Name))
 	}
-	ignored, err := git.Ignored(t.WorktreePath, paths)
+	ignored, err := git.Ignored(r.Context(), t.WorktreePath, paths)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, err)
 		return
diff --git a/internal/server/server.go b/internal/server/server.go
index 6c1d6f2..c9f1c18 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -22,6 +22,7 @@ import (
 	"g.fc.run/ai/byre/internal/store"
 	"g.fc.run/ai/byre/internal/terminal"
 	"g.fc.run/ai/byre/internal/todo"
+	"g.fc.run/ai/byre/internal/trace"
 	"g.fc.run/ai/byre/internal/workflow"
 	"tailscale.com/client/local"
 	"tailscale.com/tsnet"
@@ -86,7 +87,7 @@ func New(dataDir string, portFirst int, ts *tsnet.Server, token string) (*Server
 		return nil, err
 	}
 	for _, p := range projects {
-		err = git.ConfigureNotesFetch(p.RepoPath)
+		err = git.ConfigureNotesFetch(context.Background(), p.RepoPath)
 		if err != nil {
 			slog.Error("configure notes fetch", "project", p.Id, "repo", p.RepoPath, "err", err)
 		}
@@ -131,7 +132,7 @@ func (s *Server) Handler() http.Handler {
 			writeError(w, http.StatusBadRequest, err)
 		},
 	})
-	return http.NewCrossOriginProtection().Handler(mux)
+	return timing(http.NewCrossOriginProtection().Handler(mux))
 }
 
 func (s *Server) LoopbackHandler() http.Handler {
@@ -167,7 +168,9 @@ func (s *Server) GetTailnet(w http.ResponseWriter, r *http.Request) {
 
 func (s *Server) identify(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		identified := trace.Start(r.Context(), "whois")
 		who, err := s.tailnet.WhoIs(r.Context(), r.RemoteAddr)
+		identified()
 		if err != nil {
 			writeError(w, http.StatusUnauthorized, fmt.Errorf("identify %s on the tailnet: %w", r.RemoteAddr, err))
 			return
@@ -301,12 +304,12 @@ func (s *Server) createProject(ctx context.Context, name, repoPath, createdBy st
 		return api.Project{}, fmt.Errorf("%w: name is required", agents.ErrInvalid)
 	}
 
-	info, err := git.Inspect(repoPath)
+	info, err := git.Inspect(ctx, repoPath)
 	if err != nil {
 		return api.Project{}, fmt.Errorf("%w: %w", agents.ErrInvalid, err)
 	}
 
-	err = git.ConfigureNotesFetch(info.Root)
+	err = git.ConfigureNotesFetch(ctx, info.Root)
 	if err != nil {
 		return api.Project{}, err
 	}
@@ -439,7 +442,7 @@ func (s *Server) GetTodo(w http.ResponseWriter, r *http.Request, projectID strin
 		return
 	}
 
-	src, found, err := git.ReadFile(p.RepoPath, p.DefaultBranch, todo.File)
+	src, found, err := git.ReadFile(r.Context(), p.RepoPath, p.DefaultBranch, todo.File)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, err)
 		return
diff --git a/internal/server/timing.go b/internal/server/timing.go
new file mode 100644
index 0000000..5db636a
--- /dev/null
+++ b/internal/server/timing.go
@@ -0,0 +1,50 @@
+package server
+
+import (
+	"log/slog"
+	"net/http"
+	"time"
+
+	"g.fc.run/ai/byre/internal/trace"
+)
+
+const slowRequest = 200 * time.Millisecond
+
+type timedWriter struct {
+	http.ResponseWriter
+	start  time.Time
+	trace  *trace.Trace
+	status int
+}
+
+func (w *timedWriter) WriteHeader(status int) {
+	if w.status == 0 {
+		w.status = status
+		w.Header().Set("Server-Timing", w.trace.Header(time.Since(w.start)))
+	}
+	w.ResponseWriter.WriteHeader(status)
+}
+
+func (w *timedWriter) Write(b []byte) (int, error) {
+	if w.status == 0 {
+		w.WriteHeader(http.StatusOK)
+	}
+	return w.ResponseWriter.Write(b)
+}
+
+func (w *timedWriter) Unwrap() http.ResponseWriter {
+	return w.ResponseWriter
+}
+
+func timing(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ctx, t := trace.New(r.Context())
+		tw := &timedWriter{ResponseWriter: w, start: time.Now(), trace: t}
+		next.ServeHTTP(tw, r.WithContext(ctx))
+		took := time.Since(tw.start)
+		if took < slowRequest || tw.status == http.StatusSwitchingProtocols || tw.Header().Get("Content-Type") == "text/event-stream" {
+			return
+		}
+		slog.Info("request slow", "method", r.Method, "path", r.URL.Path, "status", tw.status, "took", took, "spans", t.String())
+	})
+}
diff --git a/internal/store/migrateids.go b/internal/store/migrateids.go
index b0c6a7e..3ea20d5 100644
--- a/internal/store/migrateids.go
+++ b/internal/store/migrateids.go
@@ -1,6 +1,7 @@
 package store
 
 import (
+	"context"
 	"database/sql"
 	"errors"
 	"fmt"
@@ -85,15 +86,15 @@ func migratePrefixIDs(tx *sql.Tx, dataDir string) error {
 		for i, w := range worktrees {
 			worktrees[i] = filepath.Dir(w)
 		}
-		err = git.RepairWorktrees(repo, worktrees)
+		err = git.RepairWorktrees(context.Background(), repo, worktrees)
 		if err != nil {
 			return err
 		}
-		err = git.RenameRefs(repo, rewrite)
+		err = git.RenameRefs(context.Background(), repo, rewrite)
 		if err != nil {
 			return err
 		}
-		err = git.RewriteNotes(repo, rewrite)
+		err = git.RewriteNotes(context.Background(), repo, rewrite)
 		if err != nil {
 			return err
 		}
diff --git a/internal/store/store.go b/internal/store/store.go
index e9a6dcc..9fa31d8 100644
--- a/internal/store/store.go
+++ b/internal/store/store.go
@@ -14,9 +14,8 @@ import (
 	"sync"
 	"time"
 
-	_ "modernc.org/sqlite"
-
 	"g.fc.run/ai/byre/internal/api"
+	"g.fc.run/ai/byre/internal/trace"
 )
 
 var ErrNotFound = errors.New("not found")
@@ -85,10 +84,11 @@ type Store struct {
 
 func Open(path string, portFirst int, onEvent func([]api.Event)) (*Store, error) {
 	dsn := "file:" + path + "?_pragma=journal_mode(WAL)&_pragma=busy_timeout(5000)&_pragma=foreign_keys(1)&_txlock=immediate"
-	db, err := sql.Open("sqlite", dsn)
+	connector, err := newTracedConnector(dsn)
 	if err != nil {
 		return nil, err
 	}
+	db := sql.OpenDB(connector)
 
 	err = migrate(db, filepath.Dir(path))
 	if err != nil {
@@ -1505,7 +1505,9 @@ func (s *Store) Counts(ctx context.Context) (Counts, error) {
 type emitFunc func(api.Event) error
 
 func (s *Store) write(ctx context.Context, fn func(tx *sql.Tx, emit emitFunc) error) error {
+	locked := trace.Start(ctx, "store lock")
 	s.writeMu.Lock()
+	locked()
 	defer s.writeMu.Unlock()
 
 	tx, err := s.db.BeginTx(ctx, nil)
diff --git a/internal/store/traced.go b/internal/store/traced.go
new file mode 100644
index 0000000..2367e3b
--- /dev/null
+++ b/internal/store/traced.go
@@ -0,0 +1,95 @@
+package store
+
+import (
+	"context"
+	"database/sql/driver"
+	"time"
+
+	"modernc.org/sqlite"
+
+	"g.fc.run/ai/byre/internal/trace"
+)
+
+type sqliteConn interface {
+	driver.Conn
+	driver.ConnBeginTx
+	driver.ConnPrepareContext
+	driver.ExecerContext
+	driver.QueryerContext
+	driver.Pinger
+	driver.SessionResetter
+	driver.Validator
+}
+
+type tracedConnector struct {
+	driver.Connector
+}
+
+func newTracedConnector(dsn string) (driver.Connector, error) {
+	c, err := sqlite.NewConnector(dsn)
+	if err != nil {
+		return nil, err
+	}
+	return tracedConnector{c}, nil
+}
+
+func (c tracedConnector) Connect(ctx context.Context) (driver.Conn, error) {
+	conn, err := c.Connector.Connect(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return tracedConn{conn.(sqliteConn)}, nil
+}
+
+type tracedConn struct {
+	sqliteConn
+}
+
+func (c tracedConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	defer trace.Start(ctx, "sql begin")()
+	return c.sqliteConn.BeginTx(ctx, opts)
+}
+
+func (c tracedConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	defer trace.Start(ctx, "sql exec")()
+	return c.sqliteConn.ExecContext(ctx, query, args)
+}
+
+func (c tracedConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	start := time.Now()
+	rows, err := c.sqliteConn.QueryContext(ctx, query, args)
+	if err != nil {
+		trace.Add(ctx, "sql query", time.Since(start))
+		return nil, err
+	}
+	return &tracedRows{sqliteRows: rows.(sqliteRows), ctx: ctx, took: time.Since(start)}, nil
+}
+
+type sqliteRows interface {
+	driver.Rows
+	driver.RowsColumnTypeDatabaseTypeName
+	driver.RowsColumnTypeLength
+	driver.RowsColumnTypeNullable
+	driver.RowsColumnTypePrecisionScale
+	driver.RowsColumnTypeScanType
+}
+
+type tracedRows struct {
+	sqliteRows
+	ctx  context.Context
+	took time.Duration
+}
+
+func (r *tracedRows) Next(dest []driver.Value) error {
+	start := time.Now()
+	err := r.sqliteRows.Next(dest)
+	r.took += time.Since(start)
+	return err
+}
+
+func (r *tracedRows) Close() error {
+	start := time.Now()
+	err := r.sqliteRows.Close()
+	trace.Add(r.ctx, "sql query", r.took+time.Since(start))
+	return err
+}
diff --git a/internal/trace/trace.go b/internal/trace/trace.go
new file mode 100644
index 0000000..3144206
--- /dev/null
+++ b/internal/trace/trace.go
@@ -0,0 +1,71 @@
+package trace
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+type span struct {
+	name string
+	dur  time.Duration
+}
+
+type Trace struct {
+	mu    sync.Mutex
+	spans []span
+}
+
+type ctxKey struct{}
+
+func New(ctx context.Context) (context.Context, *Trace) {
+	t := &Trace{}
+	return context.WithValue(ctx, ctxKey{}, t), t
+}
+
+func Start(ctx context.Context, name string) func() {
+	start := time.Now()
+	return func() {
+		Add(ctx, name, time.Since(start))
+	}
+}
+
+func Add(ctx context.Context, name string, dur time.Duration) {
+	t, _ := ctx.Value(ctxKey{}).(*Trace)
+	if t == nil {
+		return
+	}
+	t.mu.Lock()
+	t.spans = append(t.spans, span{name: name, dur: dur})
+	t.mu.Unlock()
+}
+
+func (t *Trace) Header(total time.Duration) string {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	parts := []string{fmt.Sprintf("total;dur=%.1f", ms(total))}
+	for _, s := range t.spans {
+		parts = append(parts, fmt.Sprintf("%s;dur=%.1f", token(s.name), ms(s.dur)))
+	}
+	return strings.Join(parts, ", ")
+}
+
+func (t *Trace) String() string {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	parts := []string{}
+	for _, s := range t.spans {
+		parts = append(parts, fmt.Sprintf("%s %s", s.name, s.dur.Round(time.Millisecond)))
+	}
+	return strings.Join(parts, ", ")
+}
+
+func ms(d time.Duration) float64 {
+	return float64(d.Microseconds()) / 1000
+}
+
+func token(name string) string {
+	return strings.ReplaceAll(name, " ", "-")
+}
diff --git a/mac/Sources/Byre/API.swift b/mac/Sources/Byre/API.swift
index 0e3e8f2..ff13d17 100644
--- a/mac/Sources/Byre/API.swift
+++ b/mac/Sources/Byre/API.swift
@@ -118,7 +118,7 @@ final class API: Sendable {
             "Byre-Host": macName,
         ]
         config.proxyConfigurations = [tailnetNode.proxy()]
-        session = URLSession(configuration: config)
+        session = URLSession(configuration: config, delegate: RequestTiming(), delegateQueue: nil)
         client = Client(
             serverURL: origin,
             configuration: Configuration(dateTranscoder: ByreDates()),
diff --git a/mac/Sources/Byre/RequestTiming.swift b/mac/Sources/Byre/RequestTiming.swift
new file mode 100644
index 0000000..71d9454
--- /dev/null
+++ b/mac/Sources/Byre/RequestTiming.swift
@@ -0,0 +1,41 @@
+import Foundation
+
+final class RequestTiming: NSObject, URLSessionTaskDelegate, Sendable {
+    private static let slow: TimeInterval = 0.2
+
+    func urlSession(_ session: URLSession, task: URLSessionTask, didFinishCollecting metrics: URLSessionTaskMetrics) {
+        guard let t = metrics.transactionMetrics.last, let response = t.response as? HTTPURLResponse, response.statusCode != 101, response.value(forHTTPHeaderField: "Content-Type") != "text/event-stream", let fetched = t.fetchStartDate, let sent = t.requestStartDate, let first = t.responseStartDate, let done = t.responseEndDate else {
+            return
+        }
+        let finished = Date()
+        let serverTiming = response.value(forHTTPHeaderField: "Server-Timing") ?? ""
+        let server = Self.serverTotal(serverTiming)
+        let queue = (t.connectStartDate ?? sent).timeIntervalSince(fetched)
+        let connect = t.connectStartDate.flatMap { start in t.connectEndDate.map { $0.timeIntervalSince(start) } } ?? 0
+        let network = first.timeIntervalSince(sent) - server
+        let download = done.timeIntervalSince(first)
+        let total = done.timeIntervalSince(fetched)
+        let line = "\(task.originalRequest?.httpMethod ?? "") \(task.originalRequest?.url?.path ?? "")"
+        Task { @MainActor in
+            let app = Date().timeIntervalSince(finished)
+            if total + app < Self.slow {
+                return
+            }
+            log.notice("request slow \(line, privacy: .public) total=\(Self.ms(total + app), privacy: .public) queue=\(Self.ms(queue), privacy: .public) connect=\(Self.ms(connect), privacy: .public) network=\(Self.ms(network), privacy: .public) server=\(Self.ms(server), privacy: .public) download=\(Self.ms(download), privacy: .public) app=\(Self.ms(app), privacy: .public) spans=\(serverTiming, privacy: .public)")
+        }
+    }
+
+    private static func serverTotal(_ header: String) -> TimeInterval {
+        for metric in header.split(separator: ",") {
+            let parts = metric.split(separator: ";").map { $0.trimmingCharacters(in: .whitespaces) }
+            if parts.first == "total", let dur = parts.dropFirst().first(where: { $0.hasPrefix("dur=") }), let value = Double(dur.dropFirst(4)) {
+                return value / 1000
+            }
+        }
+        return 0
+    }
+
+    private static func ms(_ seconds: TimeInterval) -> String {
+        "\(Int((seconds * 1000).rounded()))ms"
+    }
+}