Files
chrome-use/skill-data/core/references/profiling.md
T
Chris Tate 4cc6ca40b7 feat(skills): rename "agent-browser" skill to "core"; make CLI-served main skill actually useful (#1253)
Before this change, the main skill served by the CLI (`agent-browser
skills get agent-browser`) was a ~40-line discovery stub whose content
was essentially "run `agent-browser skills get <name>` before doing
anything." Agents already inside the CLI got no signal from it — the
content they needed to actually use the tool lived only in the `--full`
references.

Split the two jobs apart:

- **`skill-data/core/`** (new) — the runtime usage guide. 420-line
  `SKILL.md` covering the snapshot-and-ref loop, common workflows
  (login, extract, screenshot, multi-tab, sessions, iframes, dialogs),
  waiting strategies, element selection strategies, troubleshooting,
  and when to load a specialized skill. Supplementary `references/` and
  `templates/` (moved from `skills/agent-browser/`) provide the full
  command reference under `--full`.
- **`skills/agent-browser/SKILL.md`** — still the discovery stub that
  `npx skills add` installs, now marked `hidden: true` so it stays out
  of `skills list` inside the CLI. Body is a clean pointer to
  `agent-browser skills get core` and the specialized skills.

The `hidden: true` frontmatter flag is a new, general mechanism: skills
marked hidden are omitted from `skills list` and `skills get --all` but
can still be fetched by explicit name. This keeps the stub reachable
for anyone who installed via `npx skills add` without polluting the
CLI-side skill listing.

## Behavior

```
$ agent-browser skills list
  agentcore       Run agent-browser on AWS Bedrock AgentCore cloud browsers...
  core            Core agent-browser usage guide. Read this before running...
  dogfood         Systematically explore and test a web application...
  electron        Automate Electron desktop apps (VS Code, Slack, Discord...)
  slack           Interact with Slack workspaces using browser automation...
  vercel-sandbox  Run agent-browser + Chrome inside Vercel Sandbox microVMs...

$ agent-browser skills get core          # the actual usage guide
# ~420 lines of workflows, patterns, troubleshooting

$ agent-browser skills get agent-browser # still works if called explicitly
# the thin stub, now pointing at `core`
```

External `npx skills add vercel-labs/agent-browser` behavior is
unchanged: it finds and installs the thin `agent-browser` stub, which
tells the agent to run `agent-browser skills get core` for real
content. Version drift protection is preserved — the stub is the only
thing that gets copied; the real content is always runtime-fetched.

## Updated

- `cli/src/skills.rs` — `SkillInfo.hidden: bool`, parsed from
  frontmatter; `run_list` and `run_get --all` filter it. 3 new unit
  tests for the frontmatter parser.
- `cli/src/output.rs` — top-level `--help` and `skills` subcommand help
  reference `skills get core` / `skills get core --full`.
- `AGENTS.md` — "update these files for user-facing features" now
  points at `skill-data/core/` instead of the stub, with a note that
  the stub is not the right place for feature content.
- `README.md`, `docs/src/app/skills/page.mdx` — describe the new
  split and `skills get core --full` as the recommended entry point.
- `evals/cases/{command-usage,skill-selection}.ts` — expect
  `skills get core` in agent output instead of `skills get
  agent-browser`. Eval lib still reads `skills/agent-browser/SKILL.md`
  (simulating what an agent sees after `npx skills add`).

All 11 skills unit tests pass. `cargo clippy -- -D warnings` and
`cargo fmt --check` clean. Verified end-to-end: `skills list` shows
`core` + specialized (no stub), `skills get core` returns the new
content, `skills get agent-browser` still returns the stub on explicit
request.
2026-04-16 14:36:59 -05:00

3.3 KiB

Profiling

Capture Chrome DevTools performance profiles during browser automation for performance analysis.

Related: commands.md for full command reference, SKILL.md for quick start.

Contents

Basic Profiling

# Start profiling
agent-browser profiler start

# Perform actions
agent-browser navigate https://example.com
agent-browser click "#button"
agent-browser wait 1000

# Stop and save
agent-browser profiler stop ./trace.json

Profiler Commands

# Start profiling with default categories
agent-browser profiler start

# Start with custom trace categories
agent-browser profiler start --categories "devtools.timeline,v8.execute,blink.user_timing"

# Stop profiling and save to file
agent-browser profiler stop ./trace.json

Categories

The --categories flag accepts a comma-separated list of Chrome trace categories. Default categories include:

  • devtools.timeline -- standard DevTools performance traces
  • v8.execute -- time spent running JavaScript
  • blink -- renderer events
  • blink.user_timing -- performance.mark() / performance.measure() calls
  • latencyInfo -- input-to-latency tracking
  • renderer.scheduler -- task scheduling and execution
  • toplevel -- broad-spectrum basic events

Several disabled-by-default-* categories are also included for detailed timeline, call stack, and V8 CPU profiling data.

Use Cases

Diagnosing Slow Page Loads

agent-browser profiler start
agent-browser navigate https://app.example.com
agent-browser wait --load networkidle
agent-browser profiler stop ./page-load-profile.json

Profiling User Interactions

agent-browser navigate https://app.example.com
agent-browser profiler start
agent-browser click "#submit"
agent-browser wait 2000
agent-browser profiler stop ./interaction-profile.json

CI Performance Regression Checks

#!/bin/bash
agent-browser profiler start
agent-browser navigate https://app.example.com
agent-browser wait --load networkidle
agent-browser profiler stop "./profiles/build-${BUILD_ID}.json"

Output Format

The output is a JSON file in Chrome Trace Event format:

{
  "traceEvents": [
    { "cat": "devtools.timeline", "name": "RunTask", "ph": "X", "ts": 12345, "dur": 100, ... },
    ...
  ],
  "metadata": {
    "clock-domain": "LINUX_CLOCK_MONOTONIC"
  }
}

The metadata.clock-domain field is set based on the host platform (Linux or macOS). On Windows it is omitted.

Viewing Profiles

Load the output JSON file in any of these tools:

  • Chrome DevTools: Performance panel > Load profile (Ctrl+Shift+I > Performance)
  • Perfetto UI: https://ui.perfetto.dev/ -- drag and drop the JSON file
  • Trace Viewer: chrome://tracing in any Chromium browser

Limitations

  • Only works with Chromium-based browsers (Chrome, Edge). Not supported on Firefox or WebKit.
  • Trace data accumulates in memory while profiling is active (capped at 5 million events). Stop profiling promptly after the area of interest.
  • Data collection on stop has a 30-second timeout. If the browser is unresponsive, the stop command may fail.