Browser4 Dev

What it does

When your agent uses it

• The user asks to add a new browser4-cli command
• New tool domain
• Modify Browser4s own Kotlin/Rust code
• Check which modules a change affects

Example prompts

• “/browser4-dev”

Requirements

• Pre-approved tools (allowed-tools): coding.scaffoldFlow, coding.scaffoldFromExample, coding.mvnBuild, coding.devTask, coding.impact, coding.moduleGraph, coding.trapCheck, coding.protect, coding.scaffold, coding.write, coding.read, coding.readLines, coding.replace, coding.replaceRegex, coding.editLines, coding.insertAfter, coding.revert, coding.validate, coding.shell, coding.ktSymbols, coding.ktReferences, coding.ktInheritance, coding.diagnostics, coding.references, coding.symbols, coding.tokenStats, coding.estimateTokens

Workflow steps

10 steps, taken from the step headings in SKILL.md.

1. 1Add a new CLI command
2. 2Add a REST endpoint
3. 3Modify browser driver code
4. 4Before changing anything — know the blast radius
5. 5Add a new CLI command
6. 6Add a new agent tool domain (plugin)
7. 7Add a REST endpoint
8. 8Add a test class / skill
9. 9Clone an existing implementation (anti-staleness)
10. 10Plan a whole dev task in one call

What it can do on your machine

Read from SKILL.md and the folder at commit 0fdba82. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • coding.scaffoldFlow
  • coding.scaffoldFromExample
  • coding.mvnBuild
  • coding.devTask
  • coding.impact
  • coding.moduleGraph
  • coding.trapCheck
  • coding.protect
  • coding.scaffold
  • coding.write

  …and 17 more on the same allowed-tools line.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • cargo

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Browser4 Dev loads about 2.2k tokens when it runs. Until then it costs about 96 tokens; SKILL.md has 486 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~96

When it runs · the whole SKILL.md, loaded when a task matches

~2.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from platonai/Browser4 at commit 0fdba82, republished under its Apache-2.0 licence (© platonai). 486 words, ~2,245 tokens.

name

browser4-dev

description

Develop features inside the Browser4 repository itself: add CLI commands, agent tool domains, REST endpoints, tests, and skills; analyze impact, plan dev tasks, check CDP pitfalls, and verify builds. Use when the user asks to add a new browser4-cli command, new tool domain, REST endpoint, modify Browser4's own Kotlin/Rust code, or check which modules a change affects.

allowed-tools

coding.scaffoldFlow, coding.scaffoldFromExample, coding.mvnBuild, coding.devTask, coding.impact, coding.moduleGraph, coding.trapCheck, coding.protect, coding.scaffold, coding.write, coding.read, coding.readLines, coding.replace, coding.replaceRegex, coding.editLines, coding.insertAfter, coding.revert, coding.validate, coding.shell, coding.ktSymbols, coding.ktReferences, coding.ktInheritance, coding.diagnostics, coding.references, coding.symbols, coding.tokenStats, coding.estimateTokens

title

browser4-dev

tier

procedure

coding.scaffoldFlow(type="b4-cli-command", name="my-command", verify=true)

coding.scaffoldFlow(type="b4-cli-command", name="my-command", verify=true)
coding.mvnBuild(module="browser4-rest")

coding.scaffoldFlow(type="rest-endpoint", name="my-resource", verify=true)

coding.trapCheck(path="browser4-core/browser4-browser/src/.../PulsarWebDriver.kt")
coding.impact(path=<file>)
coding.mvnBuild(module="browser4-core/browser4-browser")

coding.moduleGraph(module="browser4-core/browser4-browser")
  → LIVE module graph rebuilt from the real pom.xml files: direct deps,
    transitive dependents, and drift warnings vs the static snapshot

coding.impact(path="browser4-core/browser4-browser/src/.../PulsarWebDriver.kt")
  → owning module + affected modules (transitively) + suggested test commands

coding.trapCheck(path=<browser-driver file>)
  → CDP pitfall advisories (mouseWheel race, cursor positioning, insertText racing)

coding.scaffoldFlow(type="b4-cli-command", name="extract-prices",
     description="Extract product prices from a page", category="Extract")
  → 4 files: commands.rs CommandDef, MCPToolController alias, backend skeleton, test

coding.write(path="cli/browser4-cli/src/commands.rs", content=<CommandDef block>)
coding.write(path="browser4-rest/.../MCPToolController.kt", content=<alias snippet>)
... write each piece ...

# Verify both sides:
coding.shell(command="cargo test --bin browser4-cli")          # Rust side
coding.mvnBuild(module="browser4-rest", goals="compile")       # Kotlin side

coding.scaffoldFlow(type="agent-tool", name="browser4-weather", domain="weather",
     basePackage="ai.platon.pulsar.weather", toolMethod="fetchWeather",
     description="Fetch weather for the current page")
  → 2 files: ToolExecutor + ToolMount auto-config

coding.mvnBuild(module="browser4-plugins/browser4-weather", goals="compile")
coding.validate(type="plugin", path="browser4-plugins/browser4-weather")

coding.scaffoldFlow(type="rest-endpoint", name="analysis",
     description="Run an analysis task")
  → 3 files: AnalysisController + AnalysisService + AnalysisControllerTest

coding.scaffoldFlow(type="test-class", name="my-tool",
     basePackage="ai.platon.pulsar.agentic.tools")
coding.scaffoldFlow(type="skill", name="browser4-myflow",
     description="A custom Browser4 flow")

# Single file:
coding.scaffoldFromExample(path="browser4-plugins/browser4-seo/.../SeoToolExecutor.kt")
  → discovery: shows parameters (basePackage, className, domain, toolMethod)
coding.scaffoldFromExample(path=<same>, basePackage="ai.platon.pulsar.weather",
     className="WeatherToolExecutor", domain="weather", toolMethod="fetchWeather")

# Whole plugin directory (cross-file consistent + stem-derived siblings):
coding.scaffoldFromExample(path="browser4-plugins/browser4-seo",
     className="WeatherToolExecutor", basePackage="ai.platon.pulsar.weather",
     domain="weather", artifactId="browser4-weather")
  → renames the executor AND sibling classes sharing the stem
    (SeoAutoConfiguration→WeatherAutoConfiguration, SeoService→WeatherService, ...)

coding.devTask(task="fix the mouseWheel race in PulsarWebDriver.kt under
     browser4-core/browser4-browser/src/main/kotlin, add a regression test",
     verify=true)
  → AGENTS.md dev-flow plan (read → impact → mvnBuild → tests → trapCheck →
    repo-consistency → commit), with the fast checks already RUN:
    compile of the inferred module, CDP trap check, repo-consistency.
    Add runTests=true to also execute the module's test suite.

User: 给 browser4-cli 加一个 extract-prices 命令
Agent: 1. coding.scaffoldFlow(type="b4-cli-command", name="extract-prices", ...)
       2. 写 commands.rs CommandDef、MCPToolController alias、后端骨架、测试
       3. coding.shell(command="cargo test --bin browser4-cli")
       4. coding.mvnBuild(module="browser4-rest", goals="compile")
       5. 报告：6 处触点全部就位，双端编译通过

User: 克隆 browser4-seo 插件成天气插件
Agent: 1. coding.scaffoldFromExample(path="browser4-plugins/browser4-seo",
          className="WeatherToolExecutor", basePackage="ai.platon.pulsar.weather",
          domain="weather", artifactId="browser4-weather")
       2. 逐文件 coding.write
       3. coding.mvnBuild(module="browser4-plugins/browser4-weather")
       4. coding.validate(type="plugin", path="browser4-plugins/browser4-weather")

© platonai, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/browser4-dev of platonai/Browser4.

Open the folder on GitHubat commit 0fdba82