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Overview

Beacon collects browser chat telemetry through an optional Chrome MV3 extension. It reads the chat streams of the sites you enable and relays them into the same local pipeline as agent activity, so browser conversations land in the runtime log next to CLI agent events. One extension covers both supported sites:

Claude.ai

Prompts, responses, and tool calls from the claude.ai chat stream.

ChatGPT

Prompts, responses, and tool activity from the chatgpt.com chat stream.
This page covers install, configuration, and verification, which are the same for both sites. The site pages cover what each one captures and where each one falls short.
The extension is in beta. It is not published on the Chrome Web Store and installs unpacked. It reads two chat streams whose APIs are private and undocumented, so a change on either site can interrupt capture until the adapter is updated.

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Prerequisites

Before installing the extension, make sure:
  • The Beacon endpoint is installed and running. The extension posts to the local collector on http://127.0.0.1:4318/v1/logs, which a default endpoint install already listens on, so no collector configuration is needed.
  • You have Chrome, or another Chromium browser that can load an unpacked MV3 extension. Firefox and Safari are not supported.
  • You have Node 22 or newer, if you are building from source rather than using a release archive.
  • You have reviewed what the extension retains. It captures full prompt and response text by default.
  • The people whose browsers it runs in know it is there, since it reads their Claude.ai and ChatGPT conversations.
Confirm the endpoint is up before installing the extension:

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Collection path

A content script running in the page’s main world tees the streamed chat response, a per-site adapter parses it into a normalized turn, and the extension’s service worker posts OTLP GenAI logs to the local collector. The beaconjson exporter converts those into endpoint events and writes them to the runtime JSONL log, alongside every other source. The extension never writes files and never contacts a remote endpoint. Delivery is queued in local extension storage and retried with backoff, so a turn survives the service worker being suspended mid-stream. Events collected this way carry harness.collection_method of otlp, and a harness name of claude_web or chatgpt_web, so browser activity stays distinguishable from CLI agents in the runtime log and the dashboard.

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Discovery and status

Beacon treats the browser extension as a user-installed source. It is not configured by beacon endpoint install, has no hook or plugin file on disk, and does not appear in beacon endpoint status, which reports on the endpoint service rather than on browser extensions. Its presence is therefore observed rather than declared: the evidence that it is working is claude_web or chatgpt_web events arriving in the runtime log. See Confirm it is working.

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Install

The extension installs unpacked through Chrome’s developer mode, so Chrome will not auto-update it. To move to a new version, download or build it again and reload.

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Build from source

No prebuilt archive is published yet, so building from source is currently the only way to get the extension. It needs Node 22 or newer and takes a few seconds:
That writes the loadable extension to browser-extension/dist. Note the full path, because Chrome asks for it when you load it:

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Use a release archive

Once an ext-v* release is published, you will be able to skip the build and download agent-beacon-browser-extension-<version>-chrome.zip with its .sha256 from the releases page, then verify and unzip it:
The archive is unsigned, so its .sha256 is the only integrity check it has. The unzipped folder is what you load, in place of dist.

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Load it in Chrome

  1. Open chrome://extensions.
  2. Turn on Developer mode, top right.
  3. Choose Load unpacked, then select the dist folder you built, or the unzipped release folder.
  4. Confirm the Agent Beacon browser collector now appears in the list and is enabled.
  5. Click the extension’s toolbar icon to check its status and, if you want, change the retention mode before capturing anything.

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Configuration

The extension is configured in its own UI, not by beacon. There is no CLI command and no config file on disk. Settings are split across two surfaces: Both sites are enabled by default. Turn one off in the options page to collect from the other alone.

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Retained content

Retention defaults to full. Browser chat telemetry has little investigative value without content, so the default keeps it, and the tradeoff is documented rather than defaulted away. Retention is enforced in the browser before anything is sent, so under metadata the text never leaves the page. Endpoint-side redaction, sanitization, truncation, and event-size limits apply to whatever is sent. Change the mode in the extension’s popup before enabling it on a machine where the same browser profile is used for personal conversations.

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Confirm it is working

Send one message on claude.ai or chatgpt.com, then look for the event:
A count of one or more means the whole path worked: the extension parsed the stream, the collector accepted the OTLP payload, and the exporter wrote a normalized event. To read one:
On a system-mode install the log lives at /var/log/beacon-agent/runtime.jsonl instead, and reading it needs sudo. Or browse the events in the local dashboard:

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Troubleshooting

If nothing arrives, work through it in this order:
  • The extension’s toolbar popup shows the queue depth and active streams. A growing queue means it captured the turn but cannot deliver it, which points at the collector rather than the adapter.
  • beacon endpoint status confirms the collector is running and listening on 4318.
  • The service worker console, reachable from chrome://extensions by clicking “service worker” under the extension, shows delivery errors.
  • A hard reload of the chat tab. The interceptor installs at document start, so a tab opened before the extension was loaded is not instrumented until it reloads.
  • Capture may be off, or off for that site. Check the popup and the options page.
Chrome also disables unpacked extensions on restart in some managed configurations. If capture stops after a browser restart, check that it is still enabled in chrome://extensions.

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Telemetry coverage

Coverage that is the same for both sites: Tool telemetry and token usage differ by site. See Claude.ai and ChatGPT.

Supported agent harnesses

Return to the runtime support overview.

Retention and redaction

How retained content is handled once it reaches the endpoint.