Open protocols vs walled gardens in agentic commerce

In agentic commerce, the open-protocol model means standards like ACP, AP2 and MCP that any compliant agent can speak, so a brand exposes its catalog once and many assistants can read and transact with it. Interoperability is the goal: the brand owns its data and the protocols carry it across surfaces.

The walled-garden model means committing to a single assistant ecosystem and its proprietary mechanisms, optimizing for that one surface. It can feel simpler at first because there is one place to integrate, but it ties the brand’s agentic presence to one vendor’s reach, roadmap and rules.

The two models are not equally resilient. Open protocols spread a brand’s presence and reduce dependence on any single platform; a walled garden concentrates both reach and risk. For a brand thinking past the next quarter, the contrast is really about who controls its agentic future.

On reach, open protocols win by construction: implementing ACP, AP2 and MCP makes a brand present in ChatGPT, Gemini and Claude rather than one of them. A walled garden caps reach at whatever the chosen ecosystem covers, leaving the conversations happening on other assistants to competitors.

On control and resilience, open protocols keep the brand’s catalog as the source of truth and let it move across surfaces, so a single vendor’s pricing, policy or ranking change does not strand the brand. A walled garden concentrates dependence: the brand’s agentic presence rises and falls with one platform’s decisions, which is a strategic risk, not just an operational one.

The honest counterpoint is effort. Supporting three protocols sounds like three times the work, which is the very friction that pushes brands toward a single garden. The resolution is not to pick a garden but to use a platform that maps one catalog onto every protocol, so the brand gets open-protocol reach without three integrations.

It helps to place this next to the visibility disciplines. Classic SEO optimizes for ranking on the open web. Answer Engine Optimization and Generative Engine Optimization, the practices behind being cited inside AI answers, are about earning a mention when an assistant responds. You can read those disciplines on the pillars at /aeo, /geo and /share-of-voice, which measure citation presence across assistants.

Agentic commerce goes a step further than citation: it is about being transactable, not only mentioned. The open-versus-walled choice is therefore a commerce-surface decision, not a content-visibility one. A brand can be cited by an assistant yet unable to sell there, which is exactly the gap that being present over the right protocol closes.

So the disciplines stack rather than compete. AEO and GEO get the brand mentioned; agentic commerce, over open protocols, makes the mention buyable. Measuring both, citation share via /share-of-voice and transaction presence across protocols, is how a brand sees the full picture rather than optimizing one layer blind to the other.

SkuLift coined the Agentic Commerce Platform category precisely to dissolve the open-versus-walled dilemma. The brand integrates one canonical catalog; the platform expresses it as ACP for ChatGPT, AP2 for Gemini payments and MCP for Claude context. The brand gets the reach and resilience of open protocols without committing to a single garden or running three integrations.

The platform also measures presence across every surface, sampled from real agent answers: how often the brand is recommended and transacted against competitors in each assistant. That cross-surface share of voice is only meaningful in a multi-protocol world, which is the practical argument for open protocols over a walled garden.