flake-update
Updates flake lock file inputs and returns structured information about what was updated.
This record as markdown: /tools/io-github-dave-london-go/flake-update.md
What flake-update does on Go
AI agents use flake-update to create or update resources in Go, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Go environment.
Why flake-update is rated Medium
This tool modifies a configuration file (flake.lock) by updating its contents, which is a reversible Write operation. It does not delete data (not Destructive), does not execute arbitrary code with unbounded effects (not Execute), and does not involve financial transactions (not Financial).
From the tool's definition Tool description states it 'Updates flake lock file inputs' — the word 'Updates' indicates modification of existing data (the flake lock file). Flake lock files are dependency lock specifications in Nix that can be regenerated but represent reproducible state.
Attacks that exploit this kind of access
The rule that runs flake-update safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Go, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For flake-update, this is the rule to start with:
flake-update 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Go, apply this rule, and every flake-update call is checked against it from then on.
Questions about flake-update
Updates flake lock file inputs and returns structured information about what was updated. It is categorised as a Write tool in the Go MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Go MCP server in PolicyLayer and add a rule for flake-update: 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 Go. Nothing to install.
flake-update 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 flake-update 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 flake-update. 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.
flake-update is provided by the Go MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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