From b55e3ad70a8e7e321e0f3991cecc8fa8fba16644 Mon Sep 17 00:00:00 2001
From: bflatastic <bombayapirat@gmail.com>
Date: Wed, 7 Oct 2026 11:50:55 +0700
Subject: [PATCH] Fix #258: the save_file tool says what it saves

It ran document.save, which keeps the document's own file and format (or
takes the format the path's extension picks), but described itself as a
native .vectorcraft save. The description now says so, with the formats
generated from SAVE_FORMATS, and points to export for the others.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/mcp/src/tests.rs | 11 +++++++++++
 crates/mcp/src/tools.rs | 15 ++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/crates/mcp/src/tests.rs b/crates/mcp/src/tests.rs
index 0cec1c75..ae33efec 100644
--- a/crates/mcp/src/tests.rs
+++ b/crates/mcp/src/tests.rs
@@ -303,6 +303,17 @@ fn inspect_document_reports_the_paint_of_type() {
     assert_eq!((t["fill"].as_str(), t["stroke"].as_str(), t["strokeWidth"].as_f64()), (Some("#0000ff"), Some("#00ff00"), Some(3.0)), "{t}");
 }
 
+/// save_file says it saves in the document's own format or the one the path's extension picks.
+#[test]
+fn save_file_describes_the_formats_it_writes() {
+    let tools = tool_definitions();
+    let d = tools.iter().find(|t| t["name"] == "save_file").and_then(|t| t["description"].as_str()).unwrap();
+    for ext in [".vectorcraft", ".vctemplate", ".pdf", ".svg", ".svgz", ".ai"] {
+        assert!(d.contains(ext), "{ext}: {d}");
+    }
+    assert!(d.contains("its own format"), "{d}");
+}
+
 #[test]
 fn errors_are_tool_results_not_crashes() {
     let mut s = server();
diff --git a/crates/mcp/src/tools.rs b/crates/mcp/src/tools.rs
index f12cb198..328fe3ce 100644
--- a/crates/mcp/src/tools.rs
+++ b/crates/mcp/src/tools.rs
@@ -2,7 +2,7 @@
 //! [`Backend`].
 
 use serde_json::{Map, Value, json};
-use vectorcraft_engine::cmd::fileio::{ARTBOARD_PARAMS, FORMATS, OPEN_EXTS};
+use vectorcraft_engine::cmd::fileio::{ARTBOARD_PARAMS, FORMATS, OPEN_EXTS, SAVE_FORMATS, format};
 
 use crate::backend::Backend;
 
@@ -57,6 +57,12 @@ fn obj(props: Value, required: &[&str]) -> Value {
     }
     o
 }
+
+/// The extension of each format Save writes, in [`SAVE_FORMATS`] order.
+fn save_extensions() -> Vec<&'static str> {
+    SAVE_FORMATS.iter().filter_map(|id| format(id)?.extensions.first().copied()).collect()
+}
+
 fn tool(name: &str, title: &str, desc: &str, schema: Value, read_only: bool) -> Value {
     json!({
         "name": name,
@@ -259,8 +265,11 @@ pub fn tool_definitions() -> Vec<Value> {
         tool(
             "save_file",
             "Save file",
-            "Save the active document in the native .vectorcraft format.",
-            obj(json!({"path": string("Destination (default: the document's current path)")}), &[]),
+            &format!(
+                "Save the active document with the engine's document.save: by default to its own file in its own format (native .vectorcraft unless it was opened from or saved as SVG, PDF or a restorable .ai). With `path`, the extension picks the format: .{}. Other formats are exports (see export). The reply's `format` says what was written and `warnings` what that format loses.",
+                save_extensions().join(", .")
+            ),
+            obj(json!({"path": string("Destination; its extension picks the format (default: the document's own file)")}), &[]),
             false,
         ),
         tool(