browser4-experience

browser4-experience is a skill for Claude Code from platonai/Browser4. It costs 42 tokens per session (2,942 once invoked), scanned A, original, Apache-2.0.

A Browser4 skill for saving and recalling knowledge from earlier browser tasks, such as selectors, steps, and known blockers.

In plain words
What is it for?
Use it to look up prior browser-task experience before acting, save what worked afterward, or inspect stored knowledge.
Why use it?
It reduces repeated work when the same or a similar website task is performed again.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions CLAUDE.md.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is **Where the knowledge lives:** the store root is the `knowledge.dir` JVM system property, defaulting to a `knowledge/` directory relative to the backend process.

Good fit Use it to look up prior browser-task experience before acting, save what worked afterward, or inspect stored knowledge.

Compare 6 skills from other repositories ↓
About the project

Browser4 is an AI-native browser engine that lets autonomous agents and people control real browsers, extract information from web pages, and automate tasks at scale. It combines browser interaction through a Rust CLI and MCP with deterministic selectors, machine-learning clustering, and language-model extraction. The catalogue entries provide skills and instructions for using Browser4.

platonai/Browser4 · 1,161 stars · on GitHub · browser4.io

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/platonai/Browser4
agentmods
npx agentmods add skills/platonai/browser4/browser4-experience

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for browser4-experience

README.md
[![agentmods](https://agentmods.dev/badge/skills/platonai/browser4/browser4-experience/github.svg)](https://agentmods.dev/skills/platonai/browser4/browser4-experience)
Your own site
<a href="https://agentmods.dev/skills/platonai/browser4/browser4-experience"><img src="https://agentmods.dev/badge/skills/platonai/browser4/browser4-experience/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for browser4-experience

Your own site · 80×15
<a href="https://agentmods.dev/skills/platonai/browser4/browser4-experience"><img src="https://agentmods.dev/badge/skills/platonai/browser4/browser4-experience.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,942 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 109
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00042 $0.02942
Opus 5.5 $0.00017 $0.01177
Sonnet 5.5 $0.00008 $0.00588
Haiku 4.5 $0.00004 $0.00294

Measured 15d ago against content hash 757b71349aec, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

browser4-experience scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 15d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/browser4-experience/SKILL.md · 238 lines

How it starts

The opening of the file, as written. The whole thing — 238 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Progressive Experience Memory (PEM)

The PEM system makes Browser4 progressively smarter: each successfully completed task deposits reusable knowledge so that future tasks — identical, similar, or on similar sites — complete faster with fewer steps.

1. Core Loop

Before task ──▶ experience_query ──▶ Get stored selectors, steps, blockers
    │                                      │
    ▼                                      ▼
Execute task                        P1: Replay directly
    │                               P2: Verify then replay
    ▼                               P3: Hint mode (verify all)
After task  ──▶ experience_save ──▶ P4: Advisory only
                                      P5: Cold start (no knowledge)

Copy-Paste Template

The experience tools are MCP tools called by the agent during browser4-cli agent run. The agent should call them as part of its tool set:

# Before starting a task — the agent calls experience_query to check prior knowledge
# After completing a task — the agent calls experience_save to persist what it learned
browser4-cli agent run "Go to https://amazon.com/dp/test and extract product details"

# To inspect stored knowledge, the agent calls experience_list
browser4-cli agent run "List experience knowledge entries for amazon"

2. Key Concepts

  • Knowledge store — a local directory tree of memory artifacts (tasks, traces, index); the store layout is described in section 8.
  • experience_save — persist a completed task's trace (selectors, steps, blockers) into the store.
  • experience_query — retrieve relevant past traces before starting a new task; returns a replay tier P1-P5.
  • experience_list — inspect what is stored, filtered by domain or intent.
  • Replay tiers — P1 (replay directly) → P5 (cold start), the confidence ladder used by the Decision Tree in section 4.

3. Command Map

experience_save

Persists a task execution trace to the knowledge store.

Argument Required Description
url Yes The URL the task operated on
trace Yes JSON-encoded ExecutionTrace (steps, selectors, extraction results)
outcome No "success" (default) or "failure"
task_type No Canonical task type (e.g., extract_product_list, publish_post)
intent No Free-text description of what the task was trying to do
facts No Retrospective knowledge patch (inline JSON, or @file.json through the CLI): selectors / interaction_hints / known_blockers / anti_patterns (camelCase and snake_case keys both accepted), merged into the (domain, intent) facts entry — the writer path for lessons learned. Refused when the entry is VERIFIED (immutable); the response then reports facts_rejected

Read the full file on GitHub · 238 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 15d ago Changed · +2 lines 757b71349aec
  2. 1mo ago Changed · +72 lines 3f954cb03242
  3. 1mo ago First seen · 164 lines · 42 tokens per session scan A fe50c286bc9f

Subscribe to this mod's changes

browser4-experience is a skill published in the GitHub repository platonai/Browser4 (1,161 stars, last pushed yesterday), licensed Apache-2.0. It adds 42 tokens to every session and 2,942 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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