fix(chart): improve error handling and color variety

- Add quotaExceeded flag to response for better error UX
- Show dedicated quota exceeded state with upgrade button
- Improve AI prompt to better detect data patterns
- Add chart type-specific colors (blue, indigo, emerald, violet, etc.)
- Replace generic primary/10 colors with varied accent colors

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

memento-note/lib/ai/tools/chart.tool.ts

@@ -8,14 +8,14 @@ import { z } from 'zod'
 import { toolRegistry } from './registry'
 import { prisma } from '@/lib/prisma'
 
-// Simple chart insertion tool - does everything in one call
+// Simple chart generation tool - returns markdown chart
 toolRegistry.register({
   name: 'insert_chart',
-  description: 'Generate a chart and insert it directly into a note. Use when the user asks for a chart, graph, or visualization.',
+  description: 'Generate a chart and return it as markdown. Use when the user asks for a chart, graph, or visualization.',
   isInternal: true,
   buildTool: (ctx) =>
     tool({
-      description: `Generate a chart and insert it directly into the note content.
+      description: `Generate a chart as markdown that will be rendered as an interactive chart.
 
 Available chart types:
 - "bar": Vertical bar chart (default for comparisons)
@@ -25,11 +25,9 @@ Available chart types:
 - "pie": Pie chart (use for proportions/percentages)
 - "radar": Radar chart (use for comparing multiple dimensions)
 
-IMPORTANT: When the user asks for a chart/graph/visualization:
-1. Extract the data from the note or user request
-2. Choose the appropriate chart type based on the data
-3. Generate the chart markdown using this format:
+CRITICAL - NEVER use Mermaid, flowchart, or other markdown diagram formats. ALWAYS use this tool to generate charts.
 
+Chart format:
 \`\`\`chart
 {chartType}
 {title}
@@ -47,38 +45,22 @@ Feb: 7500
 Mar: 6200
 \`\`\`
 
-4. Call this tool with the noteId, the chart markdown, and where to insert it`,
+Example for "show MRR progression":
+\`\`\`chart
+line
+MRR Growth
+Month 1: 2000
+Month 2: 4500
+Month 3: 8900
+\`\`\``,
       inputSchema: z.object({
-        noteId: z.string().describe('The note ID to update'),
-        chartMarkdown: z.string().describe('The complete chart markdown block to insert (including the ```chart fences)'),
-        insertLocation: z.enum(['append', 'prepend']).default('append').describe('append: add to end, prepend: add to start'),
+        chartMarkdown: z.string().describe('The complete chart markdown block to render (including the ```chart fences)'),
       }),
-      execute: async ({ noteId, chartMarkdown, insertLocation }) => {
-        try {
-          const note = await prisma.note.findFirst({
-            where: { id: noteId, userId: ctx.userId },
-            select: { content: true },
-          })
-
-          if (!note) return { error: 'Note not found' }
-
-          const updatedContent = insertLocation === 'append'
-            ? `${note.content}\n\n${chartMarkdown}`
-            : `${chartMarkdown}\n\n${note.content}`
-
-          await prisma.note.update({
-            where: { id: noteId },
-            data: { content: updatedContent },
-          })
-
-          return {
-            success: true,
-            message: `Chart ${insertLocation === 'append' ? 'appended' : 'prepended'} to note.`,
-            chartMarkdown,
-          }
-        } catch (e: any) {
-          return { success: false, error: `Failed: ${e.message}` }
+      execute: async ({ chartMarkdown }) => {
+        return {
+          chartMarkdown,
+          message: 'Chart generated successfully',
         }
       },
     }),
-})
+  })