Confirms whether an SSP/exchange is authorized to sell a publisher's inventory according to that publisher's ads.txt. This is a cache lookup against ads.txt files crawled daily across the top 10,000 publisher domains — it does NOT fetch the publisher's ads.txt live, so it is fast and adds no late...
Part of the TunnelMind Data API server.
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AI agents call sigil_verify_ads_txt to retrieve information from TunnelMind Data API 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_verify_ads_txt 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_verify_ads_txt": {}
}
}See the full TunnelMind Data API policy for all 54 tools.
These attack patterns abuse exactly the kind of access sigil_verify_ads_txt 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.
Confirms whether an SSP/exchange is authorized to sell a publisher's inventory according to that publisher's ads.txt. This is a cache lookup against ads.txt files crawled daily across the top 10,000 publisher domains — it does NOT fetch the publisher's ads.txt live, so it is fast and adds no latency to a real-time bidding decision. Use this tool when: - You are an ad-buying agent and want to confirm, pre-bid, that a supply path (publisher → exchange → seller_id) is legitimate. - You are detecting domain spoofing or unauthorized resale in a bid stream. - You want to check whether a seller is listed DIRECT or RESELLER. Do NOT use this tool when: - You want a full supply-path trust score — that endpoint is Sigil P31. - You want surveillance tracker data for the domain — use get_domain. Inputs: - publisher_domain (body, required): Publisher domain, e.g. nytimes.com. A www. prefix and scheme/path are stripped automatically. - exchange_domain (body, required): The exchange/SSP domain as it appears in ads.txt, e.g. google.com, amazon-adsystem.com. - seller_id (body, required): The publisher's seller/account ID at that exchange, e.g. pub-4177862836555934. Matched exactly. - seller_type (body, optional): DIRECT or RESELLER. When supplied it is checked against the ads.txt entry; a mismatch is reported as a warning. - resolve_chain (body, optional): When true, a matched RESELLER entry is cross-checked against the exchange's sellers.json (one authoritative hop). Returns: - verified: true (entry found), false (confidently not listed), or null (ads.txt could not be retrieved — indeterminate). - confidence: high | degraded | low | unknown. - seller_entry: the matched ads.txt line (line number, raw text, parsed fields) when verified is true; otherwise null. - ads_txt_parse_status, ads_txt_last_parsed, stale: provenance of the cached crawl this answer is derived from. - reseller_chain: empty unless resolve_chain: true and the matched entry is RESELLER — then it carries the sellers.json cross-check for the seller. - warnings: actionable flags, e.g. publisher_not_in_corpus, publisher_has_no_ads_txt, seller_type_mismatch, ads_txt_cache_stale. Cost: - Counts as one request against the daily rate limit. Latency: - Typical: <50ms (single cache lookup, no outbound fetch). p99: <120ms.. It is categorised as a Read tool in the TunnelMind Data API MCP Server, which means it retrieves data without modifying state.
Register the TunnelMind Data API MCP server in PolicyLayer and add a rule for sigil_verify_ads_txt: 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 TunnelMind Data API. Nothing to install.
sigil_verify_ads_txt 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_verify_ads_txt 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_verify_ads_txt. 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_verify_ads_txt is provided by the TunnelMind Data API MCP server (https://mcp-data.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 54 TunnelMind Data API tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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