agent-browser responses announce WebMCP catalog updates
Introduced 2026-09-16 · score 0.95
HOW TO USE IT
When agent-browser responses announce WebMCP tools on first discovery or a catalog change, select a relevant tool and fetch its schema before invoking it. After compaction or joining an existing session, list tools to recover context.
agent-browser webmcp list <tool> --frame <frame-id> --jsonagent-browser webmcp list --jsonagent-browser webmcp listWHY THIS HELPS
When inspecting a page that exposes WebMCP tools, select a relevant tool from the response summary and retrieve its full schema before invoking it.
REQUIREMENTS AND LIMITATIONS
- Version: v0.38.0
- <tool> (required): Tool name selected from the response summary.
- --frame <frame-id>: Select the tool in the specified frame; use when duplicate names require frame-aware selection.
- --json: Request JSON output; with no tool, retrieves the full catalog.
- --no-webmcp: Disable WebMCP launch features and proactive context; enabled by default in agent-browser-managed Chrome.
- Prerequisite: WebMCP is enabled by default in agent-browser-managed Chrome; the README installation instructions require installing Chrome with `agent-browser install` for first use, unless an existing supported browser installation is detected.
- WebMCP is enabled by default in agent-browser-managed Chrome.
- Automatic summaries are limited to 16 tools and 4 KiB of JSON; descriptions are shortened to 160 bytes plus a truncation marker, and oversized records are omitted.
- Summaries contain names, brief descriptions, origins, and frame IDs; schemas and annotations are not included proactively.
- Unchanged catalogs and pages without tools add no context.
- After conversation compaction or joining an existing browser session, use `webmcp list` to recover context.
- A catalog update can be triggered by full-record changes even when the brief description stays the same; refresh previously fetched schemas after an update.
- The daemon subscribes to CDP WebMCP events once per page session; late events appear on the next ordinary action.
FIRST-PARTY EVIDENCE
- https://github.com/vercel-labs/agent-browser/releases/tag/v0.38.0
- https://github.com/vercel-labs/agent-browser/pull/1842
- https://github.com/vercel-labs/agent-browser/blob/v0.38.0/README.md
Check the installed version and the source before using it. Entry JSON