matrix_sync
One-shot sync with a short server-side timeout. Returns new events, invites, and joined-room deltas since
This record as markdown: /tools/kh0pper-crow/matrix-sync.md
What matrix_sync does on Crow
AI agents call matrix_sync to retrieve information from Crow without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why matrix_sync is rated Low
The matrix_sync tool retrieves synchronization data from a Matrix server (new events, invites, room changes) without modifying, executing, or deleting anything. This is a standard Read operation. Severity is low because it only accesses the authenticated user's view of their own data and events, with no blast radius beyond information disclosure of the user's own collaboration data.
From the tool's definition Tool description states it "Returns new events, invites, and joined-room deltas" — pure retrieval of state changes with no modification, deletion, or execution of commands. The timeout mechanism indicates it is a polling/sync operation for reading data.
Attacks that exploit this kind of access
The rule that runs matrix_sync safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For matrix_sync, this is the rule to start with:
matrix_sync is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every matrix_sync call is checked against it from then on.
Questions about matrix_sync
One-shot sync with a short server-side timeout. Returns new events, invites, and joined-room deltas since. It is categorised as a Read tool in the Crow MCP Server, which means it retrieves data without modifying state.
Register the Crow MCP server in PolicyLayer and add a rule for matrix_sync: 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 Crow. Nothing to install.
matrix_sync is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the matrix_sync 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 matrix_sync. 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.
matrix_sync is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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