Anchor a SHA-256 file digest to Knox and return an affidavit architected for FRE 902(13)/(14) self-authentication. The file itself is not transmitted — the caller computes the hash and only the digest + filename + size + MIME type are anchored. Admissibility in any matter remains a determination ...
Risk signalsAccepts file system path (filename)
Part of the Knox Anchor server.
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AI agents call anchor_file_hash to retrieve information from Knox Anchor without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though anchor_file_hash only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"anchor_file_hash": {}
}
}See the full Knox Anchor policy for all 7 tools.
These attack patterns abuse exactly the kind of access anchor_file_hash gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Anchor a SHA-256 file digest to Knox and return an affidavit architected for FRE 902(13)/(14) self-authentication. The file itself is not transmitted — the caller computes the hash and only the digest + filename + size + MIME type are anchored. Admissibility in any matter remains a determination of the presiding court. Requires a Knox Bearer API key on the Authorization header — unauthenticated calls are rejected.. It is categorised as a Read tool in the Knox Anchor MCP Server, which means it retrieves data without modifying state.
Register the Knox Anchor MCP server in PolicyLayer and add a rule for anchor_file_hash: 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 Knox Anchor. Nothing to install.
anchor_file_hash 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 anchor_file_hash 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 anchor_file_hash. 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.
anchor_file_hash is provided by the Knox Anchor MCP server (https://bonissystems.com/api/knox/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 7 Knox Anchor tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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