[cost: external_io (HTTPS fetch of the x5u cert) | read-only] Verify a SIP Identity: JWS (RFC 8224 / SHAKEN). Fetches the x5u certificate, parses it, verifies the ES256 signature against the cert's public key, and optionally validates the RCD icon hash (RFC 9795). The icon-hash check accepts both...
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AI agents call validate_stir_shaken_identity to retrieve information from Sipflow 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 validate_stir_shaken_identity 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": {
"validate_stir_shaken_identity": {}
}
}See the full Sipflow policy for all 22 tools.
These attack patterns abuse exactly the kind of access validate_stir_shaken_identity 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.
[cost: external_io (HTTPS fetch of the x5u cert) | read-only] Verify a SIP Identity: JWS (RFC 8224 / SHAKEN). Fetches the x5u certificate, parses it, verifies the ES256 signature against the cert's public key, and optionally validates the RCD icon hash (RFC 9795). The icon-hash check accepts both payload.rcdi["/icn"] (RFC 9795 §6.1 spec form) and the legacy payload.rcdi["icn"] form deployed in the wild - the legacy form raises a warning unless strictRfc9795: true (then it fails). Returns per-check pass/fail/warning with details - useful for diagnosing 438 Invalid Identity Header rejections, expired certs, and tampered PASSporTs. Pair with: stir_attestation_explainer for the human-readable A/B/C interpretation; lookup_response_code(438) for the SIP-side context; lint_sip_request for non-cryptographic structural checks on the host INVITE.. It is categorised as a Read tool in the Sipflow MCP Server, which means it retrieves data without modifying state.
Register the Sipflow MCP server in PolicyLayer and add a rule for validate_stir_shaken_identity: 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 Sipflow. Nothing to install.
validate_stir_shaken_identity 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 validate_stir_shaken_identity 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 validate_stir_shaken_identity. 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.
validate_stir_shaken_identity is provided by the Sipflow MCP server (https://mcp.sipflow.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 22 Sipflow tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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