diff --git a/agent/dashboard/thread_api.py b/agent/dashboard/thread_api.py
index a6ef69c7..5954c3cd 100644
--- a/agent/dashboard/thread_api.py
+++ b/agent/dashboard/thread_api.py
@@ -53,6 +53,8 @@ _PROXY_REQUEST_TIMEOUT = httpx.Timeout(30.0, connect=5.0)
 _PROXY_STREAM_TIMEOUT = httpx.Timeout(None)
 # Sources whose threads should surface in the Agents UI (besides "dashboard").
 _SURFACED_SOURCES: tuple[str, ...] = ("dashboard", "github", "slack", "linear", "schedule")
+# PR lifecycle states surfaced to the UI for a thread's associated pull request.
+_PR_STATES: frozenset[str] = frozenset({"draft", "open", "merged", "closed"})
 
 
 def _agent_version_metadata() -> dict[str, str]:
@@ -333,11 +335,18 @@ def _thread_summary(
         summary["pr"] = {
             "number": pr_number,
             "title": pr_title if isinstance(pr_title, str) else title,
-            "state": pr_state if isinstance(pr_state, str) else "open",
+            "state": pr_state if pr_state in _PR_STATES else "open",
             "headRef": metadata.get("branch_name") or "",
             "baseRef": metadata.get("base_branch") or "main",
             "url": pr_url,
         }
+    diff_stats = metadata.get("diff_stats")
+    if isinstance(diff_stats, dict):
+        summary["diffStats"] = {
+            "files": int(diff_stats.get("files") or 0),
+            "additions": int(diff_stats.get("additions") or 0),
+            "deletions": int(diff_stats.get("deletions") or 0),
+        }
     # The transcript hydrates client-side from the SDK (`GET …/state` →
     # `stream.messages`); the summary only carries metadata.
     summary["messages"] = []
diff --git a/agent/tools/open_pull_request.py b/agent/tools/open_pull_request.py
index c41c0c3b..371fdd72 100644
--- a/agent/tools/open_pull_request.py
+++ b/agent/tools/open_pull_request.py
@@ -12,6 +12,7 @@ from langgraph_sdk import get_client
 
 from ..dashboard.agent_usage import record_agent_pr_usage
 from ..utils.github_app import get_github_app_installation_token
+from ..utils.github_comments import derive_pr_state
 
 logger = logging.getLogger(__name__)
 
@@ -118,6 +119,7 @@ async def _record_pr_telemetry(
             )
         pr_url = details.get("html_url") or pr.get("html_url")
         merged = bool(details.get("merged"))
+        is_draft = bool(details.get("draft", pr.get("draft")))
         state = details.get("state") if isinstance(details.get("state"), str) else "open"
         additions = details.get("additions") if isinstance(details.get("additions"), int) else 0
         deletions = details.get("deletions") if isinstance(details.get("deletions"), int) else 0
@@ -147,7 +149,8 @@ async def _record_pr_telemetry(
                     "agent_kind": "agent",
                     "pr_url": pr_url if isinstance(pr_url, str) else "",
                     "pr_number": pr_number,
-                    "pr_state": "merged" if merged else state,
+                    "pr_state": derive_pr_state(state=state, merged=merged, draft=is_draft),
+                    "pr_title": details.get("title") or pr.get("title"),
                     "branch_name": head,
                     "base_branch": base,
                     "diff_stats": {
diff --git a/agent/utils/github_comments.py b/agent/utils/github_comments.py
index ce57d710..7b771810 100644
--- a/agent/utils/github_comments.py
+++ b/agent/utils/github_comments.py
@@ -64,6 +64,17 @@ def verify_github_signature(body: bytes, signature: str, *, secret: str) -> bool
     return hmac.compare_digest(expected, signature)
 
 
+def derive_pr_state(*, state: str | None, merged: bool, draft: bool) -> str:
+    """Map GitHub PR fields to the dashboard's pr_state vocabulary."""
+    if merged:
+        return "merged"
+    if state == "closed":
+        return "closed"
+    if draft:
+        return "draft"
+    return "open"
+
+
 def get_thread_id_from_branch(branch_name: str) -> str | None:
     match = re.search(
         r"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}",
diff --git a/agent/webapp.py b/agent/webapp.py
index 9d43272e..be42640a 100644
--- a/agent/webapp.py
+++ b/agent/webapp.py
@@ -65,6 +65,7 @@ from .utils.github_comments import (
     OPEN_SWE_TAGS,
     GitHubAuthError,
     build_pr_prompt,
+    derive_pr_state,
     extract_pr_context,
     fetch_issue_comments,
     fetch_pr_comments_since_last_tag,
@@ -1601,6 +1602,10 @@ _SUPPORTED_GH_PULL_REQUEST_ACTIONS = frozenset(
 )
 _GH_PR_WATCH_TOGGLE_ACTIONS = frozenset(["closed", "reopened", "converted_to_draft"])
 _GH_PR_FIRST_REVIEW_ACTIONS = frozenset(["opened", "ready_for_review"])
+# PR lifecycle actions that should refresh the agent thread's tracked pr_state.
+_GH_PR_AGENT_STATE_ACTIONS = frozenset(
+    ["closed", "reopened", "converted_to_draft", "ready_for_review"]
+)
 _SUPPORTED_GH_COMMENT_ACTIONS = {
     "issue_comment": frozenset(["created", "edited"]),
     "pull_request_review_comment": frozenset(["created", "edited"]),
@@ -2220,6 +2225,56 @@ async def _get_thread_metadata_safe(thread_id: str) -> dict[str, Any] | None:
     return metadata if isinstance(metadata, dict) else {}
 
 
+def _pr_state_from_payload(payload: dict[str, Any]) -> str | None:
+    pull_request = payload.get("pull_request") if isinstance(payload, dict) else None
+    if not isinstance(pull_request, dict):
+        return None
+    state = pull_request.get("state")
+    return derive_pr_state(
+        state=state if isinstance(state, str) else None,
+        merged=bool(pull_request.get("merged")),
+        draft=bool(pull_request.get("draft")),
+    )
+
+
+async def update_agent_thread_pr_state(payload: dict[str, Any]) -> None:
+    """Keep an agent thread's tracked PR state in sync with PR lifecycle events.
+
+    The agent thread is located by the PR's html_url persisted in metadata when
+    the PR was opened (``open_pull_request``). Reviewer threads are skipped.
+    """
+    pull_request = payload.get("pull_request") if isinstance(payload, dict) else None
+    if not isinstance(pull_request, dict):
+        return
+    pr_url = pull_request.get("html_url")
+    new_state = _pr_state_from_payload(payload)
+    if not isinstance(pr_url, str) or not pr_url or new_state is None:
+        return
+
+    langgraph_client = get_client(url=LANGGRAPH_URL)
+    try:
+        threads = await langgraph_client.threads.search(metadata={"pr_url": pr_url}, limit=10)
+    except Exception:  # noqa: BLE001
+        logger.debug("Could not search threads for PR %s state update", pr_url, exc_info=True)
+        return
+
+    for thread in threads or []:
+        metadata = thread.get("metadata") if isinstance(thread, dict) else None
+        if not isinstance(metadata, dict) or metadata.get("kind") == REVIEWER_THREAD_KIND:
+            continue
+        thread_id = thread.get("thread_id") or thread.get("id")
+        if not isinstance(thread_id, str) or not thread_id:
+            continue
+        if metadata.get("pr_state") == new_state:
+            continue
+        try:
+            await langgraph_client.threads.update(
+                thread_id=thread_id, metadata={"pr_state": new_state}
+            )
+        except Exception:  # noqa: BLE001
+            logger.debug("Failed to update pr_state for thread %s", thread_id, exc_info=True)
+
+
 async def process_github_pr_close(payload: dict[str, Any]) -> None:
     """Toggle watch on the canonical reviewer thread on close/reopen/draft transitions.
 
@@ -3028,6 +3083,8 @@ async def github_webhook(request: Request, background_tasks: BackgroundTasks) ->
                 "status": "ignored",
                 "reason": f"Unsupported GitHub pull_request action: {action}",
             }
+        if action in _GH_PR_AGENT_STATE_ACTIONS:
+            background_tasks.add_task(update_agent_thread_pr_state, payload)
         if action in _GH_PR_WATCH_TOGGLE_ACTIONS:
             if not await _is_repo_enabled_for_review(webhook_repo_config):
                 return {"status": "ignored", "reason": "Repository not enabled for review"}
diff --git a/tests/test_agent_thread_pr_state.py b/tests/test_agent_thread_pr_state.py
new file mode 100644
index 00000000..61d5686c
--- /dev/null
+++ b/tests/test_agent_thread_pr_state.py
@@ -0,0 +1,91 @@
+"""Unit tests for agent-thread PR-state tracking from PR webhook events."""
+
+from __future__ import annotations
+
+from typing import Any
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from agent import webapp
+
+
+def _pr_payload(*, state: str, merged: bool = False, draft: bool = False) -> dict[str, Any]:
+    return {
+        "pull_request": {
+            "html_url": "https://github.com/lc/repo/pull/7",
+            "state": state,
+            "merged": merged,
+            "draft": draft,
+        }
+    }
+
+
+def test_pr_state_from_payload_merged() -> None:
+    assert webapp._pr_state_from_payload(_pr_payload(state="closed", merged=True)) == "merged"
+
+
+def test_pr_state_from_payload_closed() -> None:
+    assert webapp._pr_state_from_payload(_pr_payload(state="closed")) == "closed"
+
+
+def test_pr_state_from_payload_draft() -> None:
+    assert webapp._pr_state_from_payload(_pr_payload(state="open", draft=True)) == "draft"
+
+
+def test_pr_state_from_payload_open() -> None:
+    assert webapp._pr_state_from_payload(_pr_payload(state="open")) == "open"
+
+
+def test_pr_state_from_payload_missing_pull_request() -> None:
+    assert webapp._pr_state_from_payload({}) is None
+
+
+@pytest.mark.asyncio
+async def test_update_agent_thread_pr_state_updates_matching_thread() -> None:
+    fake_client = MagicMock()
+    fake_client.threads.search = AsyncMock(
+        return_value=[
+            {
+                "thread_id": "t1",
+                "metadata": {"kind": "agent", "pr_state": "draft"},
+            }
+        ]
+    )
+    fake_client.threads.update = AsyncMock()
+
+    with patch("agent.webapp.get_client", return_value=fake_client):
+        await webapp.update_agent_thread_pr_state(_pr_payload(state="closed"))
+
+    fake_client.threads.search.assert_awaited_once()
+    fake_client.threads.update.assert_awaited_once()
+    assert fake_client.threads.update.await_args.kwargs["thread_id"] == "t1"
+    assert fake_client.threads.update.await_args.kwargs["metadata"] == {"pr_state": "closed"}
+
+
+@pytest.mark.asyncio
+async def test_update_agent_thread_pr_state_skips_reviewer_threads() -> None:
+    fake_client = MagicMock()
+    fake_client.threads.search = AsyncMock(
+        return_value=[{"thread_id": "rev", "metadata": {"kind": "reviewer"}}]
+    )
+    fake_client.threads.update = AsyncMock()
+
+    with patch("agent.webapp.get_client", return_value=fake_client):
+        await webapp.update_agent_thread_pr_state(_pr_payload(state="closed"))
+
+    fake_client.threads.update.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_update_agent_thread_pr_state_noop_when_state_unchanged() -> None:
+    fake_client = MagicMock()
+    fake_client.threads.search = AsyncMock(
+        return_value=[{"thread_id": "t1", "metadata": {"pr_state": "merged"}}]
+    )
+    fake_client.threads.update = AsyncMock()
+
+    with patch("agent.webapp.get_client", return_value=fake_client):
+        await webapp.update_agent_thread_pr_state(_pr_payload(state="closed", merged=True))
+
+    fake_client.threads.update.assert_not_called()
diff --git a/tests/test_dashboard_thread_api.py b/tests/test_dashboard_thread_api.py
index 5e8696ac..3dbb3c9c 100644
--- a/tests/test_dashboard_thread_api.py
+++ b/tests/test_dashboard_thread_api.py
@@ -213,6 +213,59 @@ async def test_enrich_run_start_command_rejects_images_for_resolved_text_only_mo
     assert "does not support image input" in exc_info.value.detail
 
 
+def _thread_with_metadata(metadata: dict) -> dict:
+    return {"thread_id": "t1", "status": "idle", "metadata": metadata}
+
+
+def test_thread_summary_includes_pr_and_diff_stats() -> None:
+    summary = thread_api._thread_summary(
+        _thread_with_metadata(
+            {
+                "repo_full_name": "langchain-ai/open-swe",
+                "title": "Add feature",
+                "pr_number": 42,
+                "pr_url": "https://github.com/langchain-ai/open-swe/pull/42",
+                "pr_state": "draft",
+                "pr_title": "feat: add feature",
+                "branch_name": "open-swe/feature",
+                "base_branch": "main",
+                "diff_stats": {"files": 3, "additions": 10, "deletions": 2},
+            }
+        )
+    )
+
+    assert summary["pr"] == {
+        "number": 42,
+        "title": "feat: add feature",
+        "state": "draft",
+        "headRef": "open-swe/feature",
+        "baseRef": "main",
+        "url": "https://github.com/langchain-ai/open-swe/pull/42",
+    }
+    assert summary["diffStats"] == {"files": 3, "additions": 10, "deletions": 2}
+
+
+def test_thread_summary_defaults_unknown_pr_state_to_open() -> None:
+    summary = thread_api._thread_summary(
+        _thread_with_metadata(
+            {
+                "pr_number": 7,
+                "pr_url": "https://example.com/pull/7",
+                "pr_state": "bogus",
+            }
+        )
+    )
+
+    assert summary["pr"]["state"] == "open"
+
+
+def test_thread_summary_omits_pr_when_no_pr_metadata() -> None:
+    summary = thread_api._thread_summary(_thread_with_metadata({"title": "No PR"}))
+
+    assert "pr" not in summary
+    assert "diffStats" not in summary
+
+
 async def test_proxy_commands_lazily_creates_missing_thread_only_for_run_start(
     monkeypatch,
 ) -> None:
diff --git a/tests/test_open_pull_request.py b/tests/test_open_pull_request.py
index e0270ecf..06edb0b5 100644
--- a/tests/test_open_pull_request.py
+++ b/tests/test_open_pull_request.py
@@ -206,3 +206,19 @@ def test_error_surfaced_on_failure(monkeypatch: pytest.MonkeyPatch) -> None:
 
 async def _coro(value: Any) -> Any:
     return value
+
+
+def test_derive_pr_state_prefers_merged() -> None:
+    assert opr.derive_pr_state(state="closed", merged=True, draft=True) == "merged"
+
+
+def test_derive_pr_state_closed_over_draft() -> None:
+    assert opr.derive_pr_state(state="closed", merged=False, draft=True) == "closed"
+
+
+def test_derive_pr_state_draft() -> None:
+    assert opr.derive_pr_state(state="open", merged=False, draft=True) == "draft"
+
+
+def test_derive_pr_state_open() -> None:
+    assert opr.derive_pr_state(state="open", merged=False, draft=False) == "open"
diff --git a/ui/src/components/agents/AgentRunCard.tsx b/ui/src/components/agents/AgentRunCard.tsx
index 90390114..2d4d1da5 100644
--- a/ui/src/components/agents/AgentRunCard.tsx
+++ b/ui/src/components/agents/AgentRunCard.tsx
@@ -61,7 +61,7 @@ export function AgentRunCard({ thread }: AgentRunCardProps) {
           {hasPr ? (
             <>
               <GitPullRequestIcon className="size-3" />
-              Draft
+              <span className="capitalize">{thread.pr?.state ?? "open"}</span>
             </>
           ) : (
             <>
diff --git a/ui/src/components/agents/AgentsSidebar.tsx b/ui/src/components/agents/AgentsSidebar.tsx
index ce66f9e3..f0b96c2a 100644
--- a/ui/src/components/agents/AgentsSidebar.tsx
+++ b/ui/src/components/agents/AgentsSidebar.tsx
@@ -8,6 +8,8 @@ import {
   ChartLineUpIcon,
   ChatCircleIcon,
   CircleNotchIcon,
+  GitMergeIcon,
+  GitPullRequestIcon,
   LightningIcon,
   PlusIcon,
   TrashIcon,
@@ -46,6 +48,34 @@ const SOURCE_META: Record<AgentSource, { icon: SourceIcon; label: string }> = {
   schedule: { icon: CalendarBlankIcon, label: "Triggered from a schedule" },
 }
 
+type PrState = NonNullable<AgentThread["pr"]>["state"]
+
+const PR_STATE_META: Record<
+  PrState,
+  { icon: SourceIcon; label: string; className: string }
+> = {
+  draft: {
+    icon: GitPullRequestIcon,
+    label: "Draft pull request",
+    className: "text-[var(--ui-text-dim)]",
+  },
+  open: {
+    icon: GitPullRequestIcon,
+    label: "Open pull request",
+    className: "text-[var(--ui-success)]",
+  },
+  merged: {
+    icon: GitMergeIcon,
+    label: "Merged pull request",
+    className: "text-[var(--ui-accent)]",
+  },
+  closed: {
+    icon: GitPullRequestIcon,
+    label: "Closed pull request",
+    className: "text-[var(--ui-danger)]",
+  },
+}
+
 interface AgentsSidebarProps {
   user: SessionUser
   activeThreadId?: string
@@ -227,6 +257,8 @@ function ThreadRow({
       ? SOURCE_META[thread.source]
       : null
   const SourceIcon = source?.icon
+  const prMeta = thread.pr ? PR_STATE_META[thread.pr.state] : null
+  const PrIcon = prMeta?.icon
   const showFinishedIndicator = thread.status === "finished" && !thread.viewed
 
   const openTrace = () => {
@@ -282,6 +314,17 @@ function ThreadRow({
           <span className="min-w-0 flex-1 truncate text-xs">
             {thread.title}
           </span>
+          {prMeta && PrIcon && (
+            <PrIcon
+              className={cn(
+                "size-3.5 shrink-0 group-hover:hidden",
+                prMeta.className
+              )}
+              aria-label={prMeta.label}
+            >
+              <title>{prMeta.label}</title>
+            </PrIcon>
+          )}
           {badge && (
             <span className="shrink-0 rounded bg-[var(--ui-panel-2)] px-1.5 py-0.5 text-[10px] text-[var(--ui-text-dim)] group-hover:hidden">
               {badge}
diff --git a/ui/src/lib/agents/types.ts b/ui/src/lib/agents/types.ts
index 34f828ad..1ba1c5f4 100644
--- a/ui/src/lib/agents/types.ts
+++ b/ui/src/lib/agents/types.ts
@@ -189,7 +189,7 @@ export interface AgentThread {
   pr?: {
     number: number
     title: string
-    state: "draft" | "open" | "merged"
+    state: "draft" | "open" | "merged" | "closed"
     headRef: string
     baseRef: string
     url: string