# Pen.dev — WebMCP observations

Canonical: https://www.lazyweb.com/directory/webmcp/accelerators-2026-09-20/speedrun-70f8efdb-0078-4960-9e74-9cf4393d610b
Updated: 2026-09-20

Native WebMCP census · September 20, 2026

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

- Roster identity: Pen.dev · speedrun:70f8efdb-0078-4960-9e74-9cf4393d610b
- Program and cohort: a16z Speedrun · SR005
- Roster observed: 2026-09-20
- Official profile: <https://speedrun.a16z.com/companies/pendev>
- Listed website: <https://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.

| Context | Result | Final URL | Start | End |
| --- | --- | --- | --- | --- |
| Default Chrome | Not observed in this window | https://www.pen.dev/ | 2026-09-20 21:26 UTC | 2026-09-20 21:26 UTC |
| Experimental features enabled | Registration observed | https://www.pen.dev/ | 2026-09-20 21:49 UTC | 2026-09-20 21:49 UTC |

## Exact tool names

| Name | Default | Experimental |
| --- | --- | --- |
| `open_editor` | Not observed | Observed |

## Evidence limits

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.

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.

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

[Census directory](https://www.lazyweb.com/directory/webmcp/accelerators-2026-09-20) · [Study and methods](https://www.lazyweb.com/agent-readiness/measure-agent-distribution-without-counting-registrations) · [All row-level data](https://www.lazyweb.com/datasets/native-webmcp-census-2026-09-20.json) · [Archived WebMCP directory](https://www.lazyweb.com/webmcp)