MCPNews

The Model Context Protocol ecosystem, verified

Current spec 2026-07-28

OpenAI deprecates its _meta["openai/visibility"] tool field in favor of _meta.ui.visibility

OpenAI's plugin changelog deprecated its vendor-namespaced tool visibility field and directed developers to the shared _meta.ui namespace instead, citing ambiguity in what the private value hides. It is the only July 2026 entry on that changelog.

OpenAI deprecated its vendor-namespaced tool visibility field on July 21. The Plugin UI changelog entry reads: "Deprecated _meta["openai/visibility"] because its private value hides a tool from the model without specifying app visibility, which can make the intended audience unclear." The replacement is _meta.ui.visibility, which lets a tool declare whether it is available to the model, the app, or both.

Small as the entry is, the direction matters: a vendor-prefixed key gives way to the shared _meta.ui namespace that MCP Apps hosts read, which is the same namespace OpenAI's earlier changelog entries have been converging on since it declared ChatGPT fully compatible with the MCP Apps spec in February.

The field names are the whole story here and are copied exactly from the changelog. This is the only July 2026 entry on that changelog, and as of this writing there are no August entries.

How was this verified, and what are the sources?

Published · last verified · confidence 0.90.

  1. OpenAI developers Plugin UI changelog, entry dated 2026-07-21 "Legacy tool visibility metadata deprecated" - reads "Deprecated _meta[\"openai/visibility\"] because its private value hides a tool from the model without specifying app visibility, which can make the intended audience unclear. Use _meta.ui.visibility to choose whether a tool is available to the model, the app, or both"; it is the only July 2026 entry and there are no August entries - accessed

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