1 files changed, 97 insertions, 0 deletions
diff --git a/src/mcp/tools/update_message.c b/src/mcp/tools/update_message.c
new file mode 100644
index 0000000..aca1bed
--- /dev/null
+++ b/src/mcp/tools/update_message.c
@@ -0,0 +1,97 @@
+#include "mcp/tools/common/registry.h"
+
+#include "mcp/tools/common/common.h"
+#include "mcp/tools/common/context.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+
+static void
+call_update_message(const mcpc_tool_t *tool, mcpc_ucbr_t *result)
+{
+  tiny_mcp_tools_context_t *context = tiny_mcp_tools_context_current();
+  char *message_id = tiny_mcp_tool_get_string(tool, "message_id", TINY_MESSAGE_ID_LENGTH);
+  char *content = tiny_mcp_tool_get_string(tool, "content", TINY_CONTENT_MAX);
+  char *metadata_json = tiny_mcp_tool_get_string(tool, "metadata_json", TINY_CONTENT_MAX);
+  int32_t expected = 0;
+  mcpc_errcode_t expected_status
+      = mcpc_tool_get_tpropval_i32(tool, (const char8_t *)"expected_revision", &expected);
+  tiny_message_t parsed, updated;
+  tiny_message_patch_t patch;
+  tiny_store_status_t status;
+  tiny_json_buffer_t json;
+  bool changed = false;
+  tiny_metadata_mask_t metadata_mask = 0;
+  tiny_message_init(&parsed);
+  tiny_message_init(&updated);
+  patch.content = content;
+  patch.metadata = metadata_json ? &parsed.metadata : NULL;
+  patch.metadata_mask = 0;
+  patch.expected_revision = (uint64_t)expected;
+  patch.has_expected_revision = expected_status == MCPC_EC_0;
+  if (!context || !message_id || (!content && !metadata_json)
+      || (metadata_json && !tiny_mcp_parse_metadata(metadata_json, &parsed, &metadata_mask))
+      || (expected_status != MCPC_EC_0 && expected_status != MCPC_EC_ANYDATA_NOTFOUND)
+      || (patch.has_expected_revision && expected < 1))
+    {
+      tiny_mcp_tool_add_error(result, "VALIDATION_ERROR", "invalid update_message arguments");
+    }
+  else
+    {
+      patch.metadata_mask = metadata_mask;
+      status = tiny_store_update(context->store, message_id, &patch, &updated, &changed);
+      if (status != TINY_STORE_OK)
+        {
+          tiny_mcp_tool_add_error(
+              result, tiny_store_status_name(status), "message was not updated");
+        }
+      else
+        {
+          if (changed)
+            {
+              tiny_mcp_tools_invalidate_indexes(context);
+            }
+          tiny_json_init(&json);
+          tiny_json_raw(&json, "{\"status\":\"OK\",\"changed\":");
+          tiny_json_raw(&json, changed ? "true" : "false");
+          tiny_json_raw(&json, ",\"message\":");
+          tiny_mcp_tool_append_message(&json, &updated);
+          tiny_json_raw(&json, "}");
+          tiny_mcp_tool_add_json(result, &json);
+          tiny_json_free(&json);
+        }
+    }
+  free(message_id);
+  free(content);
+  free(metadata_json);
+  tiny_message_free(&parsed);
+  tiny_message_free(&updated);
+}
+
+bool
+tiny_mcp_register_update_message(mcpc_server_t *server)
+{
+  mcpc_tool_t *tool = tiny_mcp_tool_new("update_message",
+                                        "Update message content or metadata while preserving "
+                                        "identity, session, role, and creation time.",
+                                        call_update_message);
+  return tool
+         && tiny_mcp_tool_add_property(
+             tool, "message_id", "ULID of the live message to update.", MCPC_U8STR, true)
+         && tiny_mcp_tool_add_property(tool,
+                                       "content",
+                                       "Replacement UTF-8 content; omit to retain content.",
+                                       MCPC_U8STR,
+                                       false)
+         && tiny_mcp_tool_add_property(tool,
+                                       "metadata_json",
+                                       "Replacement metadata JSON; omit to retain metadata.",
+                                       MCPC_U8STR,
+                                       false)
+         && tiny_mcp_tool_add_property(tool,
+                                       "expected_revision",
+                                       "Optional positive revision for optimistic concurrency.",
+                                       MCPC_I32,
+                                       false)
+         && mcpc_server_add_tool(server, tool) == MCPC_EC_0;
+}