Render a chart from a JSON config. Returns a URL to the rendered image (expires after 10 min). Each call counts as one render against your monthly limit. "format" is required – set to "svg" or "png".
Part of the Charts by Szum server.
Free to start. No card required.
AI agents use render_chart to create or modify resources in Charts by Szum. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call render_chart repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Charts by Szum.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"render_chart": {
"limits": [
{
"counter": "render_chart_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Charts by Szum policy for all 5 tools.
These attack patterns abuse exactly the kind of access render_chart gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Render a chart from a JSON config. Returns a URL to the rendered image (expires after 10 min). Each call counts as one render against your monthly limit. "format" is required – set to "svg" or "png".. It is categorised as a Write tool in the Charts by Szum MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Charts by Szum MCP server in PolicyLayer and add a rule for render_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 Charts by Szum. Nothing to install.
render_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 render_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 render_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.
render_chart is provided by the Charts by Szum MCP server (https://szum.io/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 Charts by Szum tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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