Generates a heatmap chart based on a Cartesian coordinate system. It is used to visualize the intensity or density of values at the intersection of two discrete variables, suitable for revealing association patterns and distribution characteristics between variables.
AI agents use generate_heatmap_chart to create or update resources in Vchart — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Vchart environment.
This tool generates and creates visualization artifacts (charts) as data output. It does not execute arbitrary code, delete data, move money, or cause irreversible changes. Chart generation is a reversible Write operation—the output can be discarded or replaced.
From the tool's definition Tool name contains 'generate' and description states it 'Generates a heatmap chart'. The tool creates new chart visualization output.
Documented attack patterns abuse exactly the kind of access generate_heatmap_chart gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Vchart, and nothing reaches the server without passing your rules. This is the rule we recommend for generate_heatmap_chart:
{
"version": "1",
"default": "deny",
"tools": {
"generate_heatmap_chart": {
"limits": [
{
"counter": "generate_heatmap_chart_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}generate_heatmap_chart stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Generates a heatmap chart based on a Cartesian coordinate system. It is used to visualize the intensity or density of values at the intersection of two discrete variables, suitable for revealing association patterns and distribution characteristics between variables. It is categorised as a Write tool in the Vchart MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Vchart MCP server in PolicyLayer and add a rule for generate_heatmap_chart: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Vchart. Nothing to install.
generate_heatmap_chart is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the generate_heatmap_chart rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for generate_heatmap_chart. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
generate_heatmap_chart is provided by the Vchart MCP server (visactor/vchart-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 16 Vchart tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
16 Vchart tools catalogued and risk-classified — across an index of 42,500+ MCP servers.