sam_build · Awslabs Valkey MCP: Risk & Policy

WHAT IT DOES

What sam_build does on Awslabs Valkey

AI agents invoke sam_build to trigger actions in Awslabs Valkey. 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.

WHY IT NEEDS A POLICY

Why sam_build needs a policy

SAM build commands execute arbitrary build logic defined in project templates and configuration files. An AI agent given this tool could trigger unintended compilation, install malicious dependencies, or execute build scripts without proper validation. The tool description is empty, which reduces confidence slightly, but the name and server context clearly indicate code execution capabilities.

From the tool's definition Tool name 'sam_build' indicates execution of AWS SAM (Serverless Application Model) build operations. The sibling tools on this server (add_inline_policy, add_user_to_group, analyze_cdk_project) and server context (AWS Labs MCP for infrastructure) suggest…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sam_build Rate-limited

sam_build 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "sam_build": {
      "limits": [
        {
          "counter": "sam_build_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Awslabs Valkey, so you can run agents against it safely.

FAQ

Questions about sam_build

What does the sam_build tool do? +

sam_build. It is categorised as a Execute tool in the Awslabs Valkey MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on sam_build? +

Register the Awslabs Valkey MCP server in PolicyLayer and add a rule for sam_build: 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 Awslabs Valkey. Nothing to install.

What risk level is sam_build? +

sam_build is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit sam_build? +

Yes. Add a rate_limit block to the sam_build 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.

How do I block sam_build completely? +

Set action: deny in the PolicyLayer policy for sam_build. 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.

What MCP server provides sam_build? +

sam_build is provided by the Awslabs Valkey MCP server (awslabs.valkey-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.