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Native WebMCP census · September 20, 2026

Pen.dev — WebMCP observations

Tools observed on the website listed for Pen.dev, with default and experimental browser contexts shown separately.

    Read as Markdown
    Roster identity
    Pen.dev · speedrun:70f8efdb-0078-4960-9e74-9cf4393d610b
    Program and cohort
    a16z Speedrun · SR005
    Roster observed
    Official profile
    Official directory entry
    Listed website
    pencil.dev
    Browser
    153.0.8010.50

    Observation windows

    The experimental mode enabled WebMCP and WebMCPTesting. Both modes used fresh logged-out contexts and a 1.5-second settled observation window.
    Captured context, result and time in UTC
    ContextResultFinal URLStart / end
    Default ChromeNot observed in this windowpen.dev2026-09-20 21:26 UTC
    2026-09-20 21:26 UTC
    Experimental features enabledRegistration observedpen.dev2026-09-20 21:49 UTC
    2026-09-20 21:49 UTC

    Exact tool names

    Names reported by the browser registration event
    NameDefaultExperimental
    open_editorNot observedObserved

    Evidence limits

    Names and metadata describe exposed interfaces. They do not prove that a tool performs the named action or belongs to the company’s core product rather than a hosting platform.

    Passive homepage observation only. No tool was invoked. Registration does not establish execution, product quality, task success or adoption. A tool absent from one window may appear in another context.

    Default Chrome source hash
    a13198d96033ac580e0e444a91af4feb50d5994cff286daefe4d5876683e7d8f
    Default Chrome tool frame origins
    No registration observed
    Experimental features enabled source hash
    828c62e7b48a055244f7c214098b06db67b59b43b0c7bb379377a4f3f12e2e15
    Experimental features enabled tool frame origins
    https://www.pen.dev