AI agents call ksef_search_source_documents to retrieve information from KSeF MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries or retrieves local source documents and returns results marked explicitly as advisory (non-binding). It has no side effects—no data is created, modified, deleted, or executed. The context (KSeF e-invoice workflows) and sibling tools (e.g., ksef_get_invoice, ksef_list_invoices) confirm it follows the Read pattern of data retrieval with no reversible or irreversible mutations.
From the tool's definition Tool name and description indicate search functionality: 'Search local source documents; returned matches are advisory provenance only.' The word 'search' combined with 'advisory provenance only' signals a read-only operation that retrieves information…
Attacks that exploit this kind of access
Search local source documents; returned matches are advisory provenance only. It is categorised as a Read tool in the KSeF MCP MCP Server, which means it retrieves data without modifying state.
Register the KSeF MCP server in PolicyLayer and add a rule for ksef_search_source_documents: 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 KSeF MCP. Nothing to install.
ksef_search_source_documents 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 ksef_search_source_documents 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 ksef_search_source_documents. 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.
ksef_search_source_documents is provided by the KSeF MCP server (olegtyshcneko/ksef-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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