diff --git a/docs/self-evolution.md b/docs/self-evolution.md
index f48d94c..198b377 100644
--- a/docs/self-evolution.md
+++ b/docs/self-evolution.md
@@ -9,7 +9,7 @@ Historical verification snapshot: `51be33361422e55e1f2f00c33a0e0f8c56132a91`
 (the post-#54 `main` revision, captured before this #55 documentation-only
 update). Snapshot date: 2026-09-04.
 
-Current repository test count at this snapshot: **185 unittest cases**.
+Current repository test count at this snapshot: **187 unittest cases**.
 
 ## Verified surface
 
diff --git a/server.py b/server.py
index 3a3cae2..4fc2530 100644
--- a/server.py
+++ b/server.py
@@ -18,6 +18,7 @@
 import asyncio
 import queue
 import secrets
+import math
 from pathlib import Path
 from typing import Any
 from urllib.parse import urlparse
@@ -861,16 +862,23 @@ class AuthRequiredError extends Error {}
 # Routes
 # ---------------------------------------------------------------------------
 
+async def _json_object(request: Request) -> dict[str, Any]:
+    """Parse one bounded JSON object at every REST trust boundary."""
+    try:
+        body = await request.json()
+    except (ValueError, UnicodeDecodeError) as exc:
+        raise HTTPException(400, "Invalid JSON") from exc
+    if not isinstance(body, dict):
+        raise HTTPException(400, "JSON object required")
+    return body
+
 @app.post("/api/auth/session")
 async def api_auth_session(request: Request):
     """Exchange a user-entered server token for an HttpOnly browser session."""
     if not _SERVER_TOKEN:
         return {"authenticated": True}
-    try:
-        body = await request.json()
-    except Exception:
-        raise HTTPException(400, "Invalid JSON")
-    supplied = str(body.get("token", "")).strip() if isinstance(body, dict) else ""
+    body = await _json_object(request)
+    supplied = str(body.get("token", "")).strip()
     if not hmac.compare_digest(supplied, _SERVER_TOKEN):
         _audit("AUTH_FAILURE", "browser bootstrap rejected")
         response = JSONResponse({"detail": "Invalid server token"}, status_code=401)
@@ -905,12 +913,7 @@ async def chat_page():
 @app.post("/api/chat", dependencies=[Depends(require_api_access)])
 async def api_chat(request: Request):
     """Non-streaming chat endpoint."""
-    try:
-        body = await request.json()
-    except Exception:
-        raise HTTPException(400, "Invalid JSON")
-    if not isinstance(body, dict):
-        raise HTTPException(400, "JSON object required")
+    body = await _json_object(request)
     msg = _validate_message(_sanitize_api_message(str(body.get("message", "")).strip()))
     if not msg:
         raise HTTPException(400, "Empty message")
@@ -935,12 +938,7 @@ async def api_chat(request: Request):
 @app.post("/api/chat/stream", dependencies=[Depends(require_api_access)])
 async def api_chat_stream(request: Request):
     """SSE streaming chat endpoint."""
-    try:
-        body = await request.json()
-    except Exception:
-        raise HTTPException(400, "Invalid JSON")
-    if not isinstance(body, dict):
-        raise HTTPException(400, "JSON object required")
+    body = await _json_object(request)
     msg = _validate_message(_sanitize_api_message(str(body.get("message", "")).strip()))
     if not msg:
         raise HTTPException(400, "Empty message")
@@ -1098,9 +1096,7 @@ async def api_v2_memory_claims(request: Request, speaker: str | None = None, aud
 
 @app.post("/api/v2/memory/claims", dependencies=[Depends(require_api_access)])
 async def api_v2_create_memory_claim(request: Request):
-    body = await request.json()
-    if not isinstance(body, dict):
-        raise HTTPException(400, "JSON object required")
+    body = await _json_object(request)
     actor = _actor_for_request(request)
     if body.get("claim_type") == "private_fact" and body.get("speaker") not in {None, actor}:
         raise HTTPException(403, "Private claims must belong to the authenticated speaker")
@@ -1155,8 +1151,8 @@ async def api_v2_tasks(session_id: str | None = None):
 
 @app.post("/api/v2/tasks", dependencies=[Depends(require_api_access)])
 async def api_v2_create_task(request: Request):
-    body = await request.json()
-    if not isinstance(body, dict) or not str(body.get("description", "")).strip():
+    body = await _json_object(request)
+    if not isinstance(body.get("description"), str) or not body["description"].strip():
         raise HTTPException(400, "description is required")
     session = _normalise_session_id(body.get("session_id"))
     manager = _task_manager(session)
@@ -1170,11 +1166,14 @@ async def api_v2_create_task(request: Request):
         checkpoint = {"action": action, "args": body.get("args", "")}
         if isinstance(body.get("acceptance"), list) and body["acceptance"]:
             checkpoint["acceptance"] = body["acceptance"][0]
+    priority = body.get("priority", 0)
+    if isinstance(priority, bool) or not isinstance(priority, int):
+        raise HTTPException(400, "priority must be an integer")
     index = manager.add_task(
         str(body["description"]),
         dependencies=body.get("dependencies") if isinstance(body.get("dependencies"), list) else None,
         acceptance=body.get("acceptance") if isinstance(body.get("acceptance"), list) else None,
-        priority=int(body.get("priority", 0)),
+        priority=priority,
         checkpoint=checkpoint,
     )
     if not any(job.get("payload", {}).get("type") == "task_worker" for job in _scheduler.list_jobs()):
@@ -1240,9 +1239,9 @@ async def api_v2_learning_evidence(proposal_id: str):
 
 @app.post("/api/v2/learning/{proposal_id}/replay", dependencies=[Depends(require_api_access)])
 async def api_v2_learning_replay(proposal_id: str, request: Request):
-    body = await request.json()
-    if not isinstance(body, dict):
-        raise HTTPException(400, "JSON object required")
+    body = await _json_object(request)
+    if any(key in body and not isinstance(body[key], list) for key in ("candidate", "predecessor")):
+        raise HTTPException(400, "candidate and predecessor must be arrays")
     try:
         return _agent.learning_engine.record_shadow_replay(
             proposal_id, body.get("candidate", []), body.get("predecessor", []),
@@ -1253,7 +1252,9 @@ async def api_v2_learning_replay(proposal_id: str, request: Request):
 
 @app.post("/api/v2/learning/{proposal_id}/omission", dependencies=[Depends(require_api_access)])
 async def api_v2_learning_omission(proposal_id: str, request: Request):
-    body = await request.json()
+    body = await _json_object(request)
+    if any(key in body and not isinstance(body[key], list) for key in ("with_item", "without_item")):
+        raise HTTPException(400, "with_item and without_item must be arrays")
     try:
         return _agent.learning_engine.record_omission_trial(
             proposal_id, body.get("with_item", []), body.get("without_item", []),
@@ -1290,7 +1291,7 @@ async def api_v2_learning_export_capsule(proposal_id: str):
 @app.post("/api/v2/learning/capsules", dependencies=[Depends(require_api_access)])
 async def api_v2_learning_import_capsule(request: Request):
     try:
-        return _agent.learning_engine.import_capsule(await request.json())
+        return _agent.learning_engine.import_capsule(await _json_object(request))
     except ValueError as exc:
         raise HTTPException(400, str(exc)) from exc
 
@@ -1338,22 +1339,33 @@ async def api_v2_schedules():
 
 @app.post("/api/v2/schedules", dependencies=[Depends(require_api_access)])
 async def api_v2_create_schedule(request: Request):
-    body = await request.json()
-    if not isinstance(body, dict) or not str(body.get("name", "")).strip():
+    body = await _json_object(request)
+    if not isinstance(body.get("name"), str) or not body["name"].strip():
         raise HTTPException(400, "name is required")
     payload = body.get("payload") if isinstance(body.get("payload"), dict) else {}
     if not payload.get("type"):
         raise HTTPException(400, "payload.type is required")
     if "interval_seconds" in body:
-        job_id = _scheduler.schedule_every(
-            str(body["name"]), float(body["interval_seconds"]), payload=payload,
-            job_id=str(body["id"]) if body.get("id") else None,
-        )
+        interval = body["interval_seconds"]
+        if isinstance(interval, bool) or not isinstance(interval, (int, float)) or not math.isfinite(interval):
+            raise HTTPException(400, "interval_seconds must be a finite number")
+        try:
+            job_id = _scheduler.schedule_every(
+                body["name"], interval, payload=payload,
+                job_id=str(body["id"]) if body.get("id") else None,
+            )
+        except (TypeError, ValueError, OverflowError) as exc:
+            raise HTTPException(400, "invalid interval_seconds") from exc
     elif body.get("run_at"):
-        job_id = _scheduler.schedule_once(
-            str(body["name"]), str(body["run_at"]), payload=payload,
-            job_id=str(body["id"]) if body.get("id") else None,
-        )
+        if not isinstance(body["run_at"], str):
+            raise HTTPException(400, "run_at must be an ISO-8601 timestamp")
+        try:
+            job_id = _scheduler.schedule_once(
+                body["name"], body["run_at"], payload=payload,
+                job_id=str(body["id"]) if body.get("id") else None,
+            )
+        except (TypeError, ValueError, OverflowError) as exc:
+            raise HTTPException(400, "run_at must be an ISO-8601 timestamp") from exc
     else:
         raise HTTPException(400, "interval_seconds or run_at is required")
     return {"schedule": next(item for item in _scheduler.list_jobs() if item["id"] == job_id)}
@@ -1374,11 +1386,13 @@ async def api_v2_skills(status: str | None = None):
 
 @app.post("/api/v2/skills/install", dependencies=[Depends(require_api_access)])
 async def api_v2_install_skill(request: Request):
-    body = await request.json()
-    if not isinstance(body, dict) or not str(body.get("path", "")).strip():
+    body = await _json_object(request)
+    if not isinstance(body.get("path"), str) or not body["path"].strip():
         raise HTTPException(400, "path is required")
+    if "activate" in body and not isinstance(body["activate"], bool):
+        raise HTTPException(400, "activate must be a boolean")
     try:
-        return _agent.skill_registry.install(str(body["path"]), activate=bool(body.get("activate", False)))
+        return _agent.skill_registry.install(body["path"], activate=body.get("activate", False))
     except (OSError, ValueError, json.JSONDecodeError) as exc:
         raise HTTPException(400, str(exc))
 
@@ -1404,13 +1418,14 @@ async def api_v2_agents():
 
 @app.post("/api/v2/agents/run", dependencies=[Depends(require_api_access)])
 async def api_v2_run_agent(request: Request):
-    body = await request.json()
-    if not isinstance(body, dict) or not str(body.get("profile", "")).strip() or not str(body.get("task", "")).strip():
+    body = await _json_object(request)
+    if (not isinstance(body.get("profile"), str) or not body["profile"].strip()
+            or not isinstance(body.get("task"), str) or not body["task"].strip()):
         raise HTTPException(400, "profile and task are required")
     try:
         result = await asyncio.to_thread(
             _agent.subagent_manager.run,
-            str(body["profile"]), str(body["task"]),
+            body["profile"], body["task"],
             workspace_id=_agent.memory_bank.workspace_id,
         )
         return result
@@ -1432,11 +1447,8 @@ async def api_cost(scope: str = "installation", session_id: str | None = None):
 @app.post("/api/cost/reset", dependencies=[Depends(require_api_access)])
 async def api_cost_reset(request: Request):
     """Start a new durable workspace/session reporting window without deleting usage."""
-    try:
-        body = await request.json()
-    except Exception:
-        raise HTTPException(400, "Invalid JSON")
-    if not isinstance(body, dict) or body.get("confirm") != "reset-cost":
+    body = await _json_object(request)
+    if body.get("confirm") != "reset-cost":
         raise HTTPException(400, "Set confirm to reset-cost to reset a usage window")
     scope = str(body.get("scope", "workspace"))
     if scope not in {"workspace", "session"}:
@@ -1726,7 +1738,9 @@ async def mcp_endpoint(request: Request):
 async def api_transcribe(request: Request):
     """Transcribe audio to text using system tools (macOS say, Linux espeak)."""
     # This is a placeholder — real STT would use whisper or an API
-    body = await request.json() if request.headers.get("content-type") == "application/json" else {}
+    body = await _json_object(request) if request.headers.get("content-type", "").lower().startswith("application/json") else {}
+    if "text" in body and not isinstance(body["text"], str):
+        raise HTTPException(400, "text must be a string")
     text = body.get("text", "")
     return {"text": text, "source": "passthrough", "note": "Use whisper or cloud STT for real transcription"}
 
@@ -1828,7 +1842,9 @@ def _validate_webhook_url(url: str) -> bool:
 @app.post("/api/webhooks/register", dependencies=[Depends(require_api_access)])
 async def register_webhook(request: Request):
     """Register a webhook URL for event notifications."""
-    body = await request.json()
+    body = await _json_object(request)
+    if "url" in body and not isinstance(body["url"], str):
+        raise HTTPException(400, "URL required")
     url = body.get("url", "").strip()
     events = body.get("events", ["chat.completed"])
     if not url:
diff --git a/tests/test_server.py b/tests/test_server.py
index fc97103..23ccdfc 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -18,6 +18,51 @@
 
 
 class ServerBoundaryTests(unittest.TestCase):
+    def test_json_post_boundaries_reject_non_objects_and_malformed_payloads(self):
+        client = TestClient(server.app)
+        endpoints = (
+            "/api/chat", "/api/chat/stream", "/api/voice/transcribe",
+            "/api/webhooks/register", "/api/v2/agents/run", "/api/v2/memory/claims",
+            "/api/v2/schedules", "/api/v2/skills/install", "/api/v2/tasks",
+            "/api/v2/learning/capsules", "/api/v2/learning/missing/replay",
+            "/api/v2/learning/missing/omission", "/api/cost/reset",
+        )
+        for endpoint in endpoints:
+            for value in (None, [], "scalar", 7):
+                response = client.post(
+                    endpoint, content=json.dumps(value),
+                    headers={"content-type": "application/json"},
+                )
+                self.assertEqual(response.status_code, 400, f"{endpoint} accepted {value!r}: {response.text}")
+                self.assertNotIn("Traceback", response.text)
+                self.assertNotIn("AttributeError", response.text)
+            malformed = client.post(
+                endpoint, content=b"{", headers={"content-type": "application/json"},
+            )
+            self.assertEqual(malformed.status_code, 400, f"{endpoint}: {malformed.text}")
+            self.assertNotIn("Traceback", malformed.text)
+            self.assertNotIn("JSONDecodeError", malformed.text)
+
+    def test_json_post_field_validation_is_bounded_and_side_effect_free(self):
+        client = TestClient(server.app)
+        invalid = (
+            ("/api/v2/schedules", {"name": "bad", "payload": {"type": "test"},
+                                    "interval_seconds": "abc"}),
+            ("/api/v2/schedules", {"name": "bad", "payload": {"type": "test"},
+                                    "run_at": "not-a-date"}),
+            ("/api/v2/tasks", {"description": "bad", "priority": None}),
+            ("/api/v2/tasks", {"description": "bad", "priority": "high"}),
+            ("/api/voice/transcribe", {"text": []}),
+            ("/api/webhooks/register", {"url": []}),
+            ("/api/v2/agents/run", {"profile": [], "task": "bad"}),
+            ("/api/v2/skills/install", {"path": "missing", "activate": "false"}),
+        )
+        for endpoint, body in invalid:
+            response = client.post(endpoint, json=body)
+            self.assertEqual(response.status_code, 400, f"{endpoint}: {response.text}")
+            self.assertNotIn("Traceback", response.text)
+            self.assertNotIn("ValueError", response.text)
+
     def test_subagent_api_executes_allowed_file_action_and_rejects_disallowed_action(self):
         client = TestClient(server.app)
         with tempfile.TemporaryDirectory() as directory: