doca-comch

license	Apache-2.0
name	doca-comch
description	Use this skill when the user is doing hands-on DOCA Comch work on a host + BlueField pair — bringing up host ↔ DPU PCIe control-plane messaging, picking server (DPU) vs client (host) roles, choosing slow-path send-task / recv-callback vs fast-path producer / consumer, querying max-msg-size or max-clients capabilities, registering connection callbacks, or debugging DOCA_ERROR_* returns from the Comch API. Trigger even when the user does not explicitly mention "DOCA Comch" or "Comm Channel" (renamed in DOCA 2.5) — typical implicit phrasings include "send a control message from host to BlueField over PCIe", "DPU can't see the host representor", "DOCA_ERROR_NOT_PERMITTED on server_create", "DOCA_ERROR_AGAIN on task_send submit", "connect callback never fires", or "stream bulk data from a host driver to a DPU agent". Refuse and route elsewhere for installing DOCA itself, BFB / firmware bring-up, non-Comch DOCA libraries, or deploying Comch apps at scale — those belong to other skills.
metadata	{"kind":"library"}
compatibility	Requires DOCA SDK installed at /opt/mellanox/doca on Linux (Ubuntu 22.04/24.04 or RHEL/SLES) on a host + BlueField pair (the Comch channel runs over the RoCE/IB protocol, not the TCP/IP stack). Reads the user's local install via `pkg-config doca-comch` (legacy `doca-comm-channel` on installs <2.5) and inspects /opt/mellanox/doca/{lib,include,samples,applications}.

DOCA Comch

Where to start: This skill assumes DOCA is already installed and the user is doing hands-on Comch work on a BlueField + host pair with DOCA. Open TASKS.md if the user wants to do something (configure / build / modify / run / test / debug); open CAPABILITIES.md when the question is what can Comch express on this version. If the user has not installed DOCA yet, route to doca-setup first. If the user is asking "is Comch even on this DOCA" because the docs they read mention doca-comm-channel, route to CAPABILITIES.md ## Version compatibility for the 2.5 rename.

Example questions this skill answers well

The CLASSES of Comch questions this skill is built to answer, each with one worked example. The agent should treat the class as the load-bearing piece — the worked example is a single instance.

• "How do I bring up a Comch channel between host and DPU?" — worked example: "server side on the DPU, client side on the host, exchange a first control message". Answered by the role-selection + lifecycle workflow in TASKS.md ## configure + CAPABILITIES.md ## Capabilities and modes server-vs-client table.
• "How do I move bulk data over Comch with low CPU?" — worked example: "stream a 64 KiB chunk every 100 µs from the host driver to a DPU agent". Answered by the producer / consumer fast-path described in CAPABILITIES.md ## Capabilities and modes
  • the channel-setup workflow in TASKS.md ## configure step 4, with the "slow-path vs fast-path" selection rule.
• "What is the maximum message size I can send?" — worked example: "can I send a 4 MiB control message in one shot?". Answered by the capability-query rule (doca_comch_cap_get_max_msg_size) in CAPABILITIES.md ## Capabilities and modes
  • the property-set workflow in TASKS.md ## modify.
• "Why doesn't the DPU side see the representor?" — worked example: . Answered by the representor + permission overlay in