mcp-chat-cards

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Create chart card

create_chart_card

Render a dynamic SVG bar, line, pie, or donut chart with legend and collapsible data table to summarize referenced data in chat cards.

Instructions

Render a dynamically generated SVG chart card (bar, line, pie, or donut) with a legend and a collapsible data table. Use for useful graphics summarizing referenced data.

Input Schema

Name	Required	Description
`type`	Yes
`title`	Yes
`labels`	No	X-axis labels (bar/line)
`series`	No	Data series (bar/line)
`values`	No	Slices (pie/donut)
`yLabel`	No
`subtitle`	No
`tutorTerms`	No	Educational tutor terms. The first occurrence of each term in the card's visible prose is underlined; hovering ~1.2s shows the tip and notifies the host so the model can follow up. Terms are matched once per card, longest first, and never inside code samples, tooltips, or another term's tip. Matching is CASE-SENSITIVE, so "PATH" does not attach its tip to a filesystem "path"; set caseInsensitive on a term to match any casing. Term and tip are PLAIN text.
`description`	No
`contextActions`	No	Right-click menu actions the model anticipates being useful. Choosing one sends its prompt to the conversation; use {{selection}} to include the user's selected text.

Output Schema

Name	Required	Description
`card`	Yes
`parts`	Yes	Split state, present on EVERY card result so one completeness check works for all card types. Cards that cannot split always report {current:1,total:1,hasMore:false}; create_markdown_card and create_code_tour_card pack oversized content into parts and can report more. Read hasMore rather than the card title to decide whether content was withheld.
`display`	No	Present only when the host is not mounting this server's MCP Apps template (see MCP_CHAT_CARDS_RENDER): the card ships as a ready-made visualizer widget instead.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.0.0-alpha.1.0.1Oct 17, 2026

addedOutput schema / properties / display

Added value: +{
+  "additionalProperties": false,
+  "description": "Present only when the host is not mounting this server's MCP Apps template (see MCP_CHAT_CARDS_RENDER): the card ships as a ready-made visualizer widget instead.",
+  "properties": {
+    "action": {
+      "description": "What the caller must do to put the card in front of the user",
+      "type": "string"
+    },
+    "loading_messages": {
+      "description": "show_widget loading_messages",
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "shown": {
+      "description": "False: the user cannot see this card until action is taken",
+      "type": "boolean"
+    },
+    "title": {
+      "description": "show_widget title (snake_case)",
+      "type": "string"
+    },
+    "widget_code": {
+      "description": "show_widget widget_code, passed unchanged",
+      "type": "string"
+    }
+  },
+  "required": [
+    "shown",
+    "action",
+    "title",
+    "loading_messages",
+    "widget_code"
+  ],
+  "type": "object"
+}

Changed6 schema fields changedv0.1.3-alphaAug 21, 2026

removedInput schema / $schema

Removed value: -"http://json-schema.org/draft-07/schema#"

changedInput schema / properties / tutorTerms / description

Previous value: -"Educational tutor terms. The first occurrence of each term in the card's visible prose is underlined; hovering ~1.2s shows the tip and notifies the host so the model can follow up. Terms are matched once per card, longest first, and never inside code samples, tooltips, or another term's tip. Term and tip are PLAIN text."New value: +"Educational tutor terms. The first occurrence of each term in the card's visible prose is underlined; hovering ~1.2s shows the tip and notifies the host so the model can follow up. Terms are matched once per card, longest first, and never inside code samples, tooltips, or another term's tip. Matching is CASE-SENSITIVE, so \"PATH\" does not attach its tip to a filesystem \"path\"; set caseInsensitive on a term to match any casing. Term and tip are PLAIN text."

addedInput schema / properties / tutorTerms / items / properties / caseInsensitive

Added value: +{
+  "description": "Match the term regardless of letter case (default false)",
+  "type": "boolean"
+}

removedOutput schema / $schema

Removed value: -"http://json-schema.org/draft-07/schema#"

addedOutput schema / properties / parts

Added value: +{
+  "additionalProperties": false,
+  "description": "Split state, present on EVERY card result so one completeness check works for all card types. Cards that cannot split always report {current:1,total:1,hasMore:false}; create_markdown_card and create_code_tour_card pack oversized content into parts and can report more. Read hasMore rather than the card title to decide whether content was withheld.",
+  "properties": {
+    "current": {
+      "description": "Part number this result rendered (1-based)",
+      "type": "number"
+    },
+    "hasMore": {
+      "description": "True when content was withheld; call again with part: current + 1",
+      "type": "boolean"
+    },
+    "total": {
+      "description": "How many parts the content splits into",
+      "type": "number"
+    }
+  },
+  "required": [
+    "current",
+    "total",
+    "hasMore"
+  ],
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "card"
-]New value: +[
+  "card",
+  "parts"
+]

Changed1 schema field changedv0.1.1-alphaAug 12, 2026

changedInput schema / properties / tutorTerms / description

Previous value: -"Educational tutor terms. Occurrences in the card are underlined; hovering ~1.2s shows the tip and notifies the host so the model can follow up."New value: +"Educational tutor terms. The first occurrence of each term in the card's visible prose is underlined; hovering ~1.2s shows the tip and notifies the host so the model can follow up. Terms are matched once per card, longest first, and never inside code samples, tooltips, or another term's tip. Term and tip are PLAIN text."

First observedv0.0.0-alphaAug 10, 2026

TDQS

B3.2/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden. It does disclose output composition (SVG, legend, collapsible data table) and that the chart is 'dynamically generated,' which is useful. But it says nothing about rendering context, permissions, or side effects on the host.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences with the core capability front-loaded and no wasted words. Efficient for a complex tool, though the second sentence is too vague to fully earn its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values need no explanation, and the schema richly covers the nested tutorTerms/contextActions params. However, for a 10-parameter tool with no annotations, the description is thin on usage routing and rendering behavior, leaving real gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 50% and the schema already documents that labels/series are for bar-line versus values for pie-donut, plus rich descriptions for tutorTerms and contextActions. The description's enumeration of chart types merely repeats the enum and adds no meaning beyond the schema, so baseline 3 fits.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

Names a specific verb and resource ('Render a dynamically generated SVG chart card') and enumerates the supported chart types (bar, line, pie, donut) plus the legend and collapsible data table it produces. This distinguishes it from sibling card tools like create_table_card or create_markdown_card, though it never names them directly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The only guidance is 'Use for useful graphics summarizing referenced data,' which is vague and offers no when-not-to-use or alternatives. Against a large sibling set of card creators, the description does nothing to route the agent to the right one.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.