Witness one agent-reported bid or budget event into an AIT's hash-chained attestation log. Sigil validates the payload (rejecting any PII), classifies the evidence tier — anchored if a bid cites a valid Sigil token, else asserted — derives constraint violations, and signs the event. Use this tool...
Risk signalsAccepts raw HTML/template content (payload)
Part of the Sigil server.
Free to start. No card required.
AI agents call sigil_atap_witness to retrieve information from Sigil 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 sigil_atap_witness 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": {
"sigil_atap_witness": {}
}
}See the full Sigil policy for all 12 tools.
These attack patterns abuse exactly the kind of access sigil_atap_witness 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.
Witness one agent-reported bid or budget event into an AIT's hash-chained attestation log. Sigil validates the payload (rejecting any PII), classifies the evidence tier — anchored if a bid cites a valid Sigil token, else asserted — derives constraint violations, and signs the event. Use this tool when: - An ATAP-enrolled media-buyer agent submits a bid, win, loss, or budget decrement and you want it on the attestation record. Inputs: - ait (required): the AIT id. - event_type (required): bid:submitted | bid:won | bid:lost | budget:decremented. - payload (required): the event payload (see the sigil:media_buyer:v1 profile). Returns: the signed witness event(s), the assigned tier, and any derived constraint violations. (supply:verified events come from verify_supply_path, not this tool.). It is categorised as a Read tool in the Sigil MCP Server, which means it retrieves data without modifying state.
Register the Sigil MCP server in PolicyLayer and add a rule for sigil_atap_witness: 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 Sigil. Nothing to install.
sigil_atap_witness 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 sigil_atap_witness 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 sigil_atap_witness. 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.
sigil_atap_witness is provided by the Sigil MCP server (https://mcp.sigil.tunnelmind.ai/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 12 Sigil tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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