Summarize file read/write events (jdk.FileRead, jdk.FileWrite): counts, bytes, top paths, stack hotspots. Events must exist in recording; configure via start_profiling preset or settingsFile (.jfc).
Risk signalsAccepts file system path (filepath)
Part of the Javaperf server.
Free to start. No card required.
AI agents use profile_jfr_file_io to create or modify resources in Javaperf. 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 profile_jfr_file_io 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 Javaperf.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"profile_jfr_file_io": {
"limits": [
{
"counter": "profile_jfr_file_io_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Javaperf policy for all 26 tools.
These attack patterns abuse exactly the kind of access profile_jfr_file_io 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.
Summarize file read/write events (jdk.FileRead, jdk.FileWrite): counts, bytes, top paths, stack hotspots. Events must exist in recording; configure via start_profiling preset or settingsFile (.jfc).. It is categorised as a Write tool in the Javaperf MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Javaperf MCP server in PolicyLayer and add a rule for profile_jfr_file_io: 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 Javaperf. Nothing to install.
profile_jfr_file_io 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 profile_jfr_file_io 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 profile_jfr_file_io. 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.
profile_jfr_file_io is provided by the Javaperf MCP server (javaperf). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 26 Javaperf tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.