mongosh-eval
Evaluates a MongoDB expression via mongosh and returns the output.
This record as markdown: /tools/io-github-dave-london-build/mongosh-eval.md
What mongosh-eval does on Build
AI agents invoke mongosh-eval to trigger actions in Build. 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 mongosh-eval is rated High
This tool executes arbitrary MongoDB expressions through the mongosh shell. An AI agent could run any MongoDB operation including data reads, writes, deletions, or administrative commands. Since the effect depends on the expression provided and can include destructive operations (drop collections, delete documents) or data exfiltration, Execute is the appropriate category.
From the tool's definition 'Evaluates a MongoDB expression via mongosh' — runs arbitrary code/commands against a MongoDB instance
Attacks that exploit this kind of access
The rule that runs mongosh-eval safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Build, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For mongosh-eval, this is the rule to start with:
mongosh-eval 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Build, apply this rule, and every mongosh-eval call is checked against it from then on.
Questions about mongosh-eval
Evaluates a MongoDB expression via mongosh and returns the output. It is categorised as a Execute tool in the Build MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Build MCP server in PolicyLayer and add a rule for mongosh-eval: 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 Build. Nothing to install.
mongosh-eval 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 mongosh-eval 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 mongosh-eval. 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.
mongosh-eval is provided by the Build MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on Build, and thousands of servers like it.
Across the catalogue