Performs a FHIR "update" interaction by replacing an existing resource instance's content with the provided payload.
Part of the FHIR MCP Server server.
Free to start. No card required.
AI agents use update to create or modify resources in FHIR MCP Server. 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 update 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 FHIR MCP Server.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"update": {
"limits": [
{
"counter": "update_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full FHIR MCP Server policy for all 13 tools.
These attack patterns abuse exactly the kind of access update 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.
Performs a FHIR "update" interaction by replacing an existing resource instance's content with the provided payload.. It is categorised as a Write tool in the FHIR MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the FHIR MCP Server MCP server in PolicyLayer and add a rule for update: 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 FHIR MCP Server. Nothing to install.
update 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 update 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 update. 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.
update is provided by the FHIR MCP Server MCP server (pypi:fhir-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 13 FHIR MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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