diff --git a/api-reference/openapi/sessions.json b/api-reference/openapi/sessions.json
index 3b9fe1c..eeadd0b 100644
--- a/api-reference/openapi/sessions.json
+++ b/api-reference/openapi/sessions.json
@@ -137,6 +137,94 @@
             }
           }
         }
+      },
+      "patch": {
+        "operationId": "patchSessionById",
+        "summary": "Update session",
+        "description": "Renames a session or changes its status (e.g. archive / unarchive). All body fields are optional; omitted fields are left unchanged.",
+        "parameters": [
+          {
+            "name": "sessionId",
+            "in": "path",
+            "required": true,
+            "description": "The id of the session to update.",
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "required": false,
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/PatchSessionRequest"
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Session updated successfully.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/GetSessionResponse"
+                }
+              }
+            }
+          },
+          "400": {
+            "description": "Bad request — malformed JSON body.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Error"
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Unauthorized — invalid or missing API key / Bearer token.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Error"
+                }
+              }
+            }
+          },
+          "403": {
+            "description": "Forbidden — the authenticated account does not own this session.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Error"
+                }
+              }
+            }
+          },
+          "404": {
+            "description": "Not found — no session exists with the given id.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Error"
+                }
+              }
+            }
+          },
+          "500": {
+            "description": "Internal server error — the session could not be updated.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Error"
+                }
+              }
+            }
+          }
+        }
       }
     },
     "/api/sessions/{sessionId}/chats": {
@@ -346,6 +434,36 @@
           }
         }
       },
+      "PatchSessionRequest": {
+        "type": "object",
+        "description": "All fields are optional. Omitted fields are left unchanged.",
+        "properties": {
+          "title": {
+            "type": "string",
+            "description": "New display title for the session (rename)."
+          },
+          "status": {
+            "type": "string",
+            "enum": [
+              "running",
+              "completed",
+              "failed",
+              "archived"
+            ],
+            "description": "Lifecycle status (matches the DB CHECK). `running` is active / unarchived; `completed` and `failed` are terminal; `archived` archives the row. Use `running` to unarchive from `archived`."
+          },
+          "linesAdded": {
+            "type": "integer",
+            "minimum": 0,
+            "description": "Updates the persisted `lines_added` column on the session (≥ 0)."
+          },
+          "linesRemoved": {
+            "type": "integer",
+            "minimum": 0,
+            "description": "Updates the persisted `lines_removed` column on the session (≥ 0)."
+          }
+        }
+      },
       "GetSessionResponse": {
         "type": "object",
         "required": [
diff --git a/api-reference/sessions/patch.mdx b/api-reference/sessions/patch.mdx
new file mode 100644
index 0000000..f09b441
--- /dev/null
+++ b/api-reference/sessions/patch.mdx
@@ -0,0 +1,4 @@
+---
+title: "Update Session"
+openapi: "/api-reference/openapi/sessions.json PATCH /api/sessions/{sessionId}"
+---
diff --git a/docs.json b/docs.json
index 4981b27..f50b591 100644
--- a/docs.json
+++ b/docs.json
@@ -287,6 +287,7 @@
             "pages": [
               "api-reference/sessions/create",
               "api-reference/sessions/get",
+              "api-reference/sessions/patch",
               "api-reference/sessions/list-chats",
               "api-reference/sessions/create-chat"
             ]