diff --git a/.dev/status/current-handoff.md b/.dev/status/current-handoff.md
index 6a1c550..4acf9cf 100644
--- a/.dev/status/current-handoff.md
+++ b/.dev/status/current-handoff.md
@@ -1,7 +1,7 @@
 # agent-memory current handoff
 
 Status: AI-authored draft. Not yet human-approved.
-Last updated: 2026-05-01 10:21 KST
+Last updated: 2026-05-01 11:10 KST
 
 ## Trigger for the next session
 
@@ -16,7 +16,7 @@ read this file first. Do not ask the user to restate context. Verify repo state,
 
 ## Ready-to-say answer
 
-agent-memory는 v0.1.38까지 배포/Hermes QA가 완료됐고, 현재는 Priority 5 dogfood/noise monitoring의 다음 slice인 read-only observation review candidate report를 진행 중이야. 브랜치는 `feat/observation-review-candidates`, worktree는 `/Users/reddit/Project/agent-memory/.worktrees/observation-review-candidates`야. 목표는 `observations audit`의 top injected refs를 `review explain`, replacement/supersedes chain, `graph inspect` 요약과 copy-paste follow-up commands로 연결하는 거야. 자동 cleanup/mutation은 하지 않고 forensic review만 강화한다.
+agent-memory는 v0.1.39까지 배포/Hermes QA가 완료됐고, 현재는 Priority 5 dogfood/noise monitoring에서 v0.1.39 dogfood 결과를 바탕으로 `observations review-candidates`의 JSON 계약을 더 운영 친화적으로 다듬는 slice를 진행 중이야. 브랜치는 `feat/observation-review-temporal`, worktree는 `/Users/reddit/Project/agent-memory/.worktrees/observation-review-temporal`야. 목표는 review-candidates 결과에 top-level count, per-ref observation window, fact status-history summary를 추가해 historical injections와 현재 lifecycle 상태를 더 쉽게 구분하는 것이다. 자동 cleanup/mutation은 여전히 하지 않는다.
 
 ## Current repo state
 
@@ -30,19 +30,19 @@ Expected GitHub identity:
 - Use `HOME=/Users/reddit` for gh commands.
 - Remote: `origin` -> `https://github.com/cafitac/agent-memory.git`
 
-Verified base before this slice:
+Verified before this slice:
 
-- latest completed release: `v0.1.38`
-- v0.1.38 removed observation query previews, skipped Hermes doctor/test synthetic observations, added audit quality warnings, and verified a real Hermes turn used an agent-memory fact.
-- local Hermes hook uses `/Users/reddit/.agent-memory/runtime/v0.1.38/.venv/bin/agent-memory` against `/Users/reddit/.agent-memory/memory.db`.
+- latest completed release: `v0.1.39`
+- v0.1.39 added read-only `agent-memory observations review-candidates` and completed published smoke/Hermes runtime QA.
+- local Hermes hook uses `/Users/reddit/.agent-memory/runtime/v0.1.39/.venv/bin/python -m agent_memory.api.cli hermes-pre-llm-hook ...` against `/Users/reddit/.agent-memory/memory.db`.
 - root checkout was clean on `main...origin/main` except local-only untracked state.
 - open PRs were `[]`.
 
 Active slice/worktree:
 
-- branch: `feat/observation-review-candidates`
-- worktree: `/Users/reddit/Project/agent-memory/.worktrees/observation-review-candidates`
-- intended release after merge: likely `v0.1.39`
+- branch: `feat/observation-review-temporal`
+- worktree: `/Users/reddit/Project/agent-memory/.worktrees/observation-review-temporal`
+- intended release after merge: likely `v0.1.40`
 
 Expected local untracked artifacts to preserve in the root checkout:
 
@@ -54,62 +54,63 @@ Expected local untracked artifacts to preserve in the root checkout:
 
 Do not delete or commit these unless the user explicitly asks.
 
-## Current slice: observation review candidates
+## Current slice: observation review temporal summaries
 
 Goal:
 
 - Keep dogfood/noise monitoring read-only.
-- Turn `observations audit` top refs into actionable forensic review candidates.
-- Help operators see lifecycle status, replacement chains, and relation graph hints without exposing raw user queries or mutating memory.
+- Make `observations review-candidates` easier to consume from local dogfood output.
+- Add compact count/window/history summaries without exposing raw user queries and without mutating memory.
 
 Implemented so far in the active worktree:
 
-- New CLI:
-  - `agent-memory observations review-candidates <db_path> --limit N --top N --frequent-threshold N`
-- Output contract:
-  - `kind: retrieval_observation_review_candidates`
-  - `read_only: true`
-  - nested `observation_audit` payload
-  - `candidates[]` derived from `top_memory_refs`
-  - fact refs include `review_explain` payload equivalent to `review explain fact`
-  - graph summary includes depth-1 relation neighbor refs and edge count
-  - signals include existing audit signals plus `has_replacement` and `has_graph_relations` when applicable
-  - copy-paste commands for `review explain`, `review replacements`, and `graph inspect`
-- Refactored CLI review explain to reuse `_fact_review_explanation_payload`.
+- `observations audit` top refs now include `observation_window`:
+  - `first_observation_id`
+  - `first_observed_at`
+  - `latest_observation_id`
+  - `latest_observed_at`
+- `observations review-candidates` now includes top-level:
+  - `observation_count`
+  - `candidate_count`
+- Each review candidate now includes:
+  - the propagated `observation_window`
+  - `status_history_summary.transition_count`
+  - `status_history_summary.latest_transition`
 - Docs updated:
   - `README.md`
   - `docs/hermes-dogfood.md`
-- Test added in `tests/test_cli.py`:
-  - `test_python_module_cli_observations_review_candidates_explains_top_refs_without_mutation_or_raw_queries`
+- Tests updated in `tests/test_cli.py`:
+  - audit regression asserts per-ref observation window.
+  - review-candidates regression asserts top-level counts and status history summary.
 
 Verification so far:
 
 - RED confirmed:
-  - `observations review-candidates` was not a valid subcommand.
+  - focused tests failed on missing `observation_window` and top-level `observation_count`.
 - GREEN focused:
-  - `uv run pytest tests/test_cli.py::test_python_module_cli_observations_review_candidates_explains_top_refs_without_mutation_or_raw_queries -q`
-  - `1 passed`
-- Broader focused:
-  - audit, review-candidates, review explain, graph inspect CLI tests
-  - `4 passed`
-- Help smoke:
-  - `PYTHONPATH=src uv run python -m agent_memory.api.cli observations review-candidates --help`
-  - exit 0
+  - `TMPDIR=$PWD/.tmp-test uv run pytest tests/test_cli.py::test_python_module_cli_observations_audit_reports_frequent_and_stale_refs_without_raw_queries tests/test_cli.py::test_python_module_cli_observations_review_candidates_explains_top_refs_without_mutation_or_raw_queries -q`
+  - `2 passed`
 
 Remaining before PR:
 
-1. Run full local verification:
+1. Run broader/full local verification:
+   - focused CLI tests around audit/review-candidates
    - `uv run pytest tests/ -q`
    - `uv run python scripts/check_release_metadata.py`
    - `uv run python scripts/smoke_release_readiness.py`
    - `npm pack --dry-run`
    - `git diff --check`
    - `node --check bin/agent-memory.js`
-2. Run real temp-DB smoke for `observations review-candidates` and confirm no raw secret-like query text appears.
+2. Run real local DB smoke for `observations review-candidates` and verify the new fields exist.
 3. Run static diff secret scan.
 4. Create PR, watch CI, merge, follow release-sync/publish/published smoke/Hermes QA.
-5. After v0.1.39 install, repeat Hermes hook doctor and run installed `observations review-candidates` against the existing local DB.
+5. After v0.1.40 install, repeat Hermes hook doctor and installed `observations review-candidates` against the existing local DB.
 
 ## Next natural slice after this one
 
-After the read-only review candidate report is released and dogfooded, continue gathering real observation data. If enough non-synthetic observations accumulate, the next likely work is retrieval quality diagnostics for high empty-retrieval ratios or scope/ranking misses. Avoid automatic cleanup/deprecation until the review candidate workflow has been used on real local data.
+After the review-candidates contract is released and dogfooded, continue Priority 5 by either:
+
+1. improving retrieval diagnostics for empty retrieval/high empty ratio, or
+2. adding an explicit human review cadence/checklist around candidate reports.
+
+Avoid automatic cleanup/deprecation until the review candidate workflow has been used on real local data for a while.
diff --git a/README.md b/README.md
index 7fc7659..0aedead 100644
--- a/README.md
+++ b/README.md
@@ -112,7 +112,7 @@ agent-memory observations audit "$DB" --limit 200 --top 10 --frequent-threshold
 agent-memory observations review-candidates "$DB" --limit 200 --top 10 --frequent-threshold 3
 ```
 
-Use the observation log and audit report to spot frequently injected or surprising memories before changing retrieval behavior. The audit output is read-only JSON with surface/scope counts, empty-retrieval count and ratio, quality warnings such as `low_observation_count` or `high_empty_retrieval_ratio`, top injected memory refs, current status for known refs, and simple signals such as `frequently_injected` and `current_status_not_approved`. `observations review-candidates` is also read-only; it turns the top audit refs into forensic candidates with fact review explanations, replacement-chain hints, graph-neighborhood summaries, and copy-paste follow-up commands such as `review explain`, `review replacements`, and `graph inspect`. Treat these reports as local operator telemetry, not a synced analytics feature or an automatic cleanup workflow.
+Use the observation log and audit report to spot frequently injected or surprising memories before changing retrieval behavior. The audit output is read-only JSON with surface/scope counts, empty-retrieval count and ratio, quality warnings such as `low_observation_count` or `high_empty_retrieval_ratio`, top injected memory refs, current status for known refs, per-ref observation windows, and simple signals such as `frequently_injected` and `current_status_not_approved`. `observations review-candidates` is also read-only; it turns the top audit refs into forensic candidates with top-level `observation_count`/`candidate_count`, fact review explanations, status-history summaries, replacement-chain hints, graph-neighborhood summaries, and copy-paste follow-up commands such as `review explain`, `review replacements`, and `graph inspect`. Treat these reports as local operator telemetry, not a synced analytics feature or an automatic cleanup workflow.
 
 ## Hermes quickstart
 
diff --git a/docs/hermes-dogfood.md b/docs/hermes-dogfood.md
index 0ef9525..0a3d948 100644
--- a/docs/hermes-dogfood.md
+++ b/docs/hermes-dogfood.md
@@ -58,7 +58,8 @@ Use this before tuning ranking or adding broader graph traversal: first confirm
 - fact refs include the same lifecycle explanation as `agent-memory review explain fact ...`.
 - replacement/supersedes chains are surfaced as candidate signals instead of mutating anything.
 - relation graph neighbors are summarized so you know when `agent-memory graph inspect ...` is worth running.
-- the JSON includes copy-paste follow-up commands for `review explain`, `review replacements`, and `graph inspect`.
+- the JSON includes `observation_count`/`candidate_count`, each ref's observation window, and copy-paste follow-up commands for `review explain`, `review replacements`, and `graph inspect`.
+- fact refs include a `status_history_summary` so historical injections that were later deprecated/superseded are easier to distinguish from currently approved frequent memories.
 
 Do not treat review candidates as automatic cleanup recommendations. They are a short list for human review; approve/deprecate/supersede decisions should still be explicit curation actions.
 
diff --git a/src/agent_memory/api/cli.py b/src/agent_memory/api/cli.py
index f517bc6..5b69e90 100644
--- a/src/agent_memory/api/cli.py
+++ b/src/agent_memory/api/cli.py
@@ -197,6 +197,7 @@ def _audit_retrieval_observations(
     )
     memory_ref_counts: Counter[str] = Counter()
     sample_observation_ids_by_ref: dict[str, list[int]] = defaultdict(list)
+    observation_windows_by_ref: dict[str, dict[str, Any]] = {}
     empty_retrieval_count = 0
     for observation in observations:
         if not observation.retrieved_memory_refs:
@@ -206,6 +207,21 @@ def _audit_retrieval_observations(
             sample_ids = sample_observation_ids_by_ref[memory_ref]
             if len(sample_ids) < 5:
                 sample_ids.append(observation.id)
+            window = observation_windows_by_ref.setdefault(
+                memory_ref,
+                {
+                    "first_observation_id": observation.id,
+                    "first_observed_at": observation.created_at,
+                    "latest_observation_id": observation.id,
+                    "latest_observed_at": observation.created_at,
+                },
+            )
+            if observation.id < window["first_observation_id"]:
+                window["first_observation_id"] = observation.id
+                window["first_observed_at"] = observation.created_at
+            if observation.id > window["latest_observation_id"]:
+                window["latest_observation_id"] = observation.id
+                window["latest_observed_at"] = observation.created_at
 
     top_memory_refs = []
     for memory_ref, injection_count in sorted(memory_ref_counts.items(), key=lambda item: (-item[1], item[0]))[:top]:
@@ -222,6 +238,7 @@ def _audit_retrieval_observations(
                 "current_status": current_status,
                 "signals": signals,
                 "sample_observation_ids": sample_observation_ids_by_ref[memory_ref],
+                "observation_window": observation_windows_by_ref[memory_ref],
             }
         )
 
@@ -282,6 +299,12 @@ def _review_candidates_from_observations(
         if graph["edges"]:
             signals.append("has_graph_relations")
 
+        history = review_explain["history"] if review_explain is not None else []
+        status_history_summary = {
+            "transition_count": len(history),
+            "latest_transition": history[-1] if history else None,
+        }
+
         commands = {"graph_inspect": f"agent-memory graph inspect {db_path} {memory_ref} --depth 1"}
         if parts is not None:
             memory_type, memory_id = parts
@@ -299,6 +322,7 @@ def _review_candidates_from_observations(
                 **top_ref,
                 "signals": signals,
                 "review_explain": review_explain,
+                "status_history_summary": status_history_summary,
                 "graph_summary": {
                     "start_ref": graph["start_ref"],
                     "depth": graph["depth"],
@@ -313,6 +337,8 @@ def _review_candidates_from_observations(
     return {
         "kind": "retrieval_observation_review_candidates",
         "read_only": True,
+        "observation_count": audit["observation_count"],
+        "candidate_count": len(candidates),
         "observation_audit": audit,
         "candidates": candidates,
     }
diff --git a/tests/test_cli.py b/tests/test_cli.py
index f6f2d39..329a8bc 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -257,6 +257,9 @@ def test_python_module_cli_observations_audit_reports_frequent_and_stale_refs_wi
     assert top_ref["current_status"] == "deprecated"
     assert top_ref["signals"] == ["frequently_injected", "current_status_not_approved"]
     assert top_ref["sample_observation_ids"]
+    assert top_ref["observation_window"]["first_observation_id"] <= top_ref["observation_window"]["latest_observation_id"]
+    assert top_ref["observation_window"]["first_observed_at"]
+    assert top_ref["observation_window"]["latest_observed_at"]
     assert "SUPERSECRET" not in audit_result.stdout
     assert "abc123" not in audit_result.stdout
 
@@ -351,6 +354,8 @@ def test_python_module_cli_observations_review_candidates_explains_top_refs_with
     payload = json.loads(review_result.stdout)
     assert payload["kind"] == "retrieval_observation_review_candidates"
     assert payload["read_only"] is True
+    assert payload["observation_count"] == 2
+    assert payload["candidate_count"] == 1
     assert payload["observation_audit"]["kind"] == "retrieval_observation_audit"
     assert payload["observation_audit"]["read_only"] is True
     candidate = payload["candidates"][0]
@@ -363,6 +368,11 @@ def test_python_module_cli_observations_review_candidates_explains_top_refs_with
         "has_replacement",
         "has_graph_relations",
     ]
+    assert candidate["observation_window"]["first_observation_id"] <= candidate["observation_window"]["latest_observation_id"]
+    assert candidate["observation_window"]["first_observed_at"]
+    assert candidate["observation_window"]["latest_observed_at"]
+    assert candidate["status_history_summary"]["transition_count"] == 2
+    assert candidate["status_history_summary"]["latest_transition"]["to_status"] == "deprecated"
     assert candidate["review_explain"]["decision"]["visible_in_default_retrieval"] is False
     assert candidate["review_explain"]["replacement_chain"]["superseded_by"][0]["replacement_fact_id"] == replacement_fact.id
     assert candidate["graph_summary"]["edge_count"] == 1