Generates a dynamic bar chart which is suitable for displaying changing data and can be used to show ranking, comparisons or data changes over time. The x field and the time field MUST be different. It updates the data dynamically according to the time field.
AI agents use generate_dynamic_bar_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 creates or modifies chart visualization data structures in a reversible manner. It does not execute arbitrary code, delete data, move money, or cause external side effects beyond chart generation. The 'dynamic' nature refers to time-based animation/updates within the visualization itself, not to executing arbitrary operations.
From the tool's definition Tool description states it 'Generates a dynamic bar chart' and 'updates the data dynamically according to the time field.' The term 'generates' and 'updates' indicate creation and modification of visualization artifacts.
Documented attack patterns abuse exactly the kind of access generate_dynamic_bar_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_dynamic_bar_chart:
{
"version": "1",
"default": "deny",
"tools": {
"generate_dynamic_bar_chart": {
"limits": [
{
"counter": "generate_dynamic_bar_chart_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}generate_dynamic_bar_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.
Free to start. No card required.
Generates a dynamic bar chart which is suitable for displaying changing data and can be used to show ranking, comparisons or data changes over time. The x field and the time field MUST be different. It updates the data dynamically according to the time field. 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_dynamic_bar_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_dynamic_bar_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_dynamic_bar_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_dynamic_bar_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_dynamic_bar_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.