[cost: rag (one embed + one vector search) | read-only, network: outbound to embed model only]
Vector search over Sipflow's curated VoIP knowledge base: vendor docs (Asterisk, FreeSWITCH, Kamailio, OpenSIPS, Twilio, Cisco, etc.), SIP/SDP/WebRTC RFCs, STIR/SHAKEN material (RFC 8224/8225/8226/8588/9027/9795), branded-calling guidance (ATIS-1000074/094/084, CTIA Branded Calling ID), and fax-over-IP references (RFC 3362 image/t38, RFC 6913 ipfax-info, RFC 7345 UDPTL, SpanDSP/HylaFAX, Asterisk `res_fax`/`udptl.conf`, FreeSWITCH `mod_spandsp`/`t38_gateway`, Cisco CUBE T.38).
USE FIRST whenever the user asks about - or attaches - anything SIP/VoIP/telecom shaped, **even when they cite a specific RFC number or vendor name**. The corpus has the current text and your training data may not. Trigger conditions: vendor configs (kamailio.cfg, sip.conf, pjsip.conf, FreeSWITCH XML profile, opensips.cfg, `res_fax.conf` / `udptl.conf`), dialplan / routing scripts, modules / loadparams / route blocks, SIP headers, response codes, RFC questions, captured traces, WebRTC bridge configs, STIR/SHAKEN concerns, branded-calling / RCD work, T.38 / T.30 fax decoding or reinvite failures.
Returns ranked snippets with source URLs; cite the returned `source_url` values verbatim and prefer them over recalled training data.
Examples of when to use:
- "does this kamailio.cfg look standard for WebRTC + SIP users?"
- "why would Asterisk PJSIP reject this re-INVITE?"
- "what does Kamailio's loose_route() do? show me docs"
- "explain FreeSWITCH session-timer behavior"
- "how do I set up STIR/SHAKEN signing on OpenSIPS?"
- "what does ATIS-1000074 say about A-level attestation?"
- "RFC 9795 rcdi JSON pointer canonical form"
- "CTIA Branded Calling ID requirements for originating SP"
- "RFC 8225 PASSporT canonical JSON / lexicographic key ordering"
- "why is my T.38 reinvite getting 488 from a Cisco CUBE?"
- "Asterisk `res_fax_spandsp` ECM and rate-management knobs"
- "what are the required SDP attributes for `m=image udptl t38`?"
Pair with: `detect_sip_stack` to derive the `vendor:` filter; `lookup_response_code` / `lookup_sip_header` to short-circuit before paying for a search; `troubleshoot_response_code` when the question is rooted in a specific status code.
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