Add a comment to an existing HackerOne report. Use this to respond to triage questions or provide additional information.
AI agents use add_comment to create or update resources in HackerOne MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your HackerOne MCP Server environment.
The tool creates new data (comments) attached to reports, which is a reversible modification operation. While the server description emphasizes read-only access, this specific tool explicitly performs a write action by adding comments. This is less severe than Execute (no code/commands run) or Destructive (comments can be deleted/edited), placing it in Write category.
From the tool's definition 'Add a comment to an existing HackerOne report' — this modifies report state by appending new data (comments) to an existing report resource.
Documented attack patterns abuse exactly the kind of access add_comment gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and HackerOne MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for add_comment:
{
"version": "1",
"default": "deny",
"tools": {
"add_comment": {
"limits": [
{
"counter": "add_comment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_comment 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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Add a comment to an existing HackerOne report. Use this to respond to triage questions or provide additional information. It is categorised as a Write tool in the HackerOne MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the HackerOne MCP Server MCP server in PolicyLayer and add a rule for add_comment: 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 HackerOne MCP Server. Nothing to install.
add_comment 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 add_comment 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 add_comment. 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.
add_comment is provided by the HackerOne MCP Server MCP server (sicks3c/hackerone-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 HackerOne MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
16 HackerOne MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.