AI agents invoke bearer_scan to trigger actions in SAST MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The description is empty, so classification is inferred from context. Bearer is a known SAST tool that scans source code for security vulnerabilities and sensitive data exposure. Based on the naming pattern of sibling tools (all _scan suffix tools that execute security scanning engines), this tool likely runs the Bearer scanner against target code. Executing an external security scanning tool qualifies as Execute.
From the tool's definition Tool name 'bearer_scan' on a SAST MCP server alongside sibling tools like bandit_scan, brakeman_scan, checkov_scan, clamav_scan — all of which are static analysis scanner execution tools.
Documented attack patterns abuse exactly the kind of access bearer_scan gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and SAST MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for bearer_scan:
{
"version": "1",
"default": "deny",
"tools": {
"bearer_scan": {
"limits": [
{
"counter": "bearer_scan_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}bearer_scan stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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bearer_scan. It is categorised as a Execute tool in the SAST MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the SAST MCP Server MCP server in PolicyLayer and add a rule for bearer_scan: 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 SAST MCP Server. Nothing to install.
bearer_scan is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the bearer_scan 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 bearer_scan. 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.
bearer_scan is provided by the SAST MCP Server MCP server (sengtocxoen/sast-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from SAST MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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39 SAST MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.