rsync
Syncs files between local and remote locations using rsync. WARNING: Defaults to dry-run mode for safety — set dryRun=false to actually transfer files. Returns structured transfer statistics.
This record as markdown: /tools/io-github-dave-london-build/rsync.md
What rsync does on Build
AI agents invoke rsync 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 rsync is rated High
rsync executes file transfer operations between local and remote systems. While it defaults to dry-run for safety, when dryRun=false it performs actual file transfers that can overwrite existing files on remote systems. This constitutes an Execute-level action with potentially destructive side effects (overwriting remote files), though it's not purely destructive since it's a sync operation.
From the tool's definition 'Syncs files between local and remote locations using rsync' and 'set dryRun=false to actually transfer files'
Attacks that exploit this kind of access
The rule that runs rsync 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 rsync, this is the rule to start with:
rsync 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 rsync call is checked against it from then on.
Questions about rsync
Syncs files between local and remote locations using rsync. WARNING: Defaults to dry-run mode for safety — set dryRun=false to actually transfer files. Returns structured transfer statistics. 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 rsync: 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.
rsync 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 rsync 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 rsync. 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.
rsync 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.
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