feat(mcp-server): load .drawio.svg, change summary, XML reference by topic, preview options, truncation message (#982)

* feat(mcp-server): load .drawio.svg (Editable SVG) files with load_diagram * feat(mcp-server): summarize the user's manual changes per cell in stale rejections and get_diagram * feat(mcp-server): XML reference for tables, layers and groups via get_drawing_guide topic * feat(mcp-server): DRAWIO_LANG, DRAWIO_UI and DRAWIO_DARK for the preview page Three host-config environment variables fix the language, theme and dark mode of the draw.io editor embedded in the preview page. The new drawio-themes module holds the theme list and draw.io's locale names (zh-hant becomes zh-tw); drawioEmbedParams() in http-server.ts builds the variable tail of the iframe query and getHtmlPage fills the new {{DRAWIO_PARAMS}} placeholder. Without the variables the page keeps sending dark=auto as before. Both READMEs document the variables. * feat(mcp-server): report XML cut off inside a cell and explain drawing in parts create_new_diagram and add_page now detect bare-cell XML that ends inside an unfinished mxCell (XML comments stripped first) and return an error with the last 300 characters of the input, asking the model to resend from that cell or continue with edit_diagram add operations. isMxCellXmlComplete moves from lib/utils.ts into packages/mcp-server/src/new-diagram.ts and is re-exported from lib/utils.ts for the web app. The drawing guide gains a "Large diagrams" paragraph and the INSTRUCTIONS edit_diagram line mentions drawing in parts. * fix(mcp-server): review fixes for load .drawio.svg, change summary, XML reference, draw.io embed options, truncation message * fix(mcp-server): Codex review fixes for .drawio.svg loading, change summary, references, embed options and truncation - Truncation check: a closing tag such as </mxCell/> that the auto-fix repairs is no cut, and input without any cell keeps the validator's message - Guide: a call rejected as cut off drew nothing, so all of its cells are sent again; the topic pointer is its own paragraph - Change summary: decoded labels (no   or merged words from <br>), a fast path for equal XML, and "the order of the cells changed" as the fallback - DRAWIO_UI in any case, DRAWIO_LANG=zh-Hans maps to draw.io's zh - load_diagram and export_diagram describe which files load again
2026-10-12 12:39:52 +08:00 · 2026-10-11 20:40:05 +09:00
parent cb066a4825
commit 8ab837679e
19 changed files with 949 additions and 146 deletions
@@ -19,6 +19,7 @@ beforeAll(() => {
 import {
    checkEditGate,
    contentFingerprint,
+    describeChanges,
    markPageSeen,
 } from "../src/edit-gate.ts"

@@ -168,3 +169,139 @@ describe("markPageSeen", () => {
        expect(markPageSeen("", live, { page_id: "A" })).toBe(live)
    })
 })
+
+describe("describeChanges", () => {
+    const BOX2 = `<mxCell id="box2" value="World" vertex="1" parent="1"><mxGeometry x="200" y="40" width="120" height="60" as="geometry"/></mxCell>`
+    const XML_A_PLUS_BOX2 = XML_A.replace("</root>", `${BOX2}</root>`)
+    const PAGE_2 = `<diagram id="p2" name="Page-2"><mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/></root></mxGraphModel></diagram>`
+    const XML_A_TWO_PAGES = XML_A.replace("</mxfile>", `${PAGE_2}</mxfile>`)
+
+    it("names a moved cell with its label", () => {
+        const summary = describeChanges(XML_A, XML_B)
+        expect(summary).toBe(
+            'Since you last saw it, the user changed the diagram: modified box1 ("Hello").',
+        )
+        expect(summary).toContain("modified box1")
+    })
+
+    it("names a deleted cell", () => {
+        expect(describeChanges(XML_A_PLUS_BOX2, XML_A)).toContain(
+            'removed box2 ("World")',
+        )
+    })
+
+    it("names an added cell", () => {
+        expect(describeChanges(XML_A, XML_A_PLUS_BOX2)).toContain(
+            'added box2 ("World")',
+        )
+    })
+
+    it("is empty for draw.io's re-serialisation of the same content", () => {
+        expect(describeChanges(XML_A, XML_A_RESERIALIZED)).toBe("")
+    })
+
+    it("is empty when the model has seen nothing yet", () => {
+        expect(describeChanges("", XML_B)).toBe("")
+    })
+
+    it("is empty when one side does not parse", () => {
+        expect(describeChanges(XML_A, "not xml at all")).toBe("")
+    })
+
+    it("reports a renamed page", () => {
+        const renamed = XML_A.replace('name="Page-1"', 'name="Renamed"')
+        expect(describeChanges(XML_A, renamed)).toBe(
+            'Since you last saw it, the user changed the diagram. Page 1 renamed to "Renamed".',
+        )
+    })
+
+    // A bare <mxGraphModel> push carries no page name, so the invented
+    // "Page-1" must not read as a rename
+    it("never reports a rename against a bare mxGraphModel", () => {
+        const seenRenamed = XML_A.replace('name="Page-1"', 'name="Arch"')
+        expect(describeChanges(seenRenamed, XML_A_BARE)).toBe("")
+        const bareMoved = XML_A_BARE.replace('x="40" y="40"', 'x="300" y="200"')
+        const summary = describeChanges(seenRenamed, bareMoved)
+        expect(summary).toContain("modified box1")
+        expect(summary).not.toContain("renamed")
+    })
+
+    it("strips HTML from labels and reads UserObject labels", () => {
+        const html = XML_A.replace(
+            'value="Hello"',
+            'value="&lt;b&gt;Hello&lt;/b&gt;"',
+        )
+        expect(describeChanges(XML_A, html)).toContain(
+            'modified box1 ("Hello")',
+        )
+        const userObject = XML_A.replace(
+            "</root>",
+            `<UserObject id="u1" label="&lt;i&gt;Link&lt;/i&gt;" link="https://x.y"><mxCell style="rounded=1;" vertex="1" parent="1"><mxGeometry x="0" y="0" width="80" height="40" as="geometry"/></mxCell></UserObject></root>`,
+        )
+        expect(describeChanges(XML_A, userObject)).toContain(
+            'added u1 ("Link")',
+        )
+    })
+
+    it("keeps the words of an HTML label apart and decodes its spaces", () => {
+        const lines = XML_A.replace(
+            'value="Hello"',
+            'value="Line1&lt;br&gt;Line2&amp;nbsp;end &amp;amp; more"',
+        )
+        expect(describeChanges(XML_A, lines)).toContain(
+            'modified box1 ("Line1 Line2 end & more")',
+        )
+    })
+
+    it("cuts long labels at 30 characters", () => {
+        const long = "a".repeat(40)
+        const summary = describeChanges(
+            XML_A,
+            XML_A.replace('value="Hello"', `value="${long}"`),
+        )
+        expect(summary).toContain(`("${"a".repeat(30)}...")`)
+    })
+
+    it("lists at most 20 cells and counts the rest", () => {
+        const many = Array.from(
+            { length: 25 },
+            (_, i) => `<mxCell id="n${i}" vertex="1" parent="1"/>`,
+        ).join("")
+        const summary = describeChanges(
+            XML_A,
+            XML_A.replace("</root>", `${many}</root>`),
+        )
+        expect(summary).toContain("added n0, n1,")
+        expect(summary).toContain("n19 and 5 more.")
+        expect(summary).not.toContain("n20")
+    })
+
+    it("reports added and removed pages", () => {
+        expect(describeChanges(XML_A, XML_A_TWO_PAGES)).toBe(
+            "Since you last saw it, the user changed the diagram: page 2 added.",
+        )
+        expect(describeChanges(XML_A_TWO_PAGES, XML_A)).toBe(
+            "Since you last saw it, the user changed the diagram: page 2 removed.",
+        )
+    })
+
+    it("names the page of a cell change in a multi-page document", () => {
+        const movedOnPage1 = XML_A_TWO_PAGES.replace(
+            'x="40" y="40"',
+            'x="300" y="200"',
+        )
+        expect(describeChanges(XML_A_TWO_PAGES, movedOnPage1)).toContain(
+            'page 1 modified box1 ("Hello")',
+        )
+    })
+
+    it("falls back to a generic clause when only the cell order changed", () => {
+        const reordered = XML_A_PLUS_BOX2.replace(BOX2, "").replace(
+            '<mxCell id="box1"',
+            `${BOX2}<mxCell id="box1"`,
+        )
+        expect(describeChanges(XML_A_PLUS_BOX2, reordered)).toBe(
+            "Since you last saw it, the user changed the diagram: the order of the cells changed.",
+        )
+    })
+})