Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add operasoftware/opera-devtools-mcp --skill chrome-devtoolsgit clone --depth 1 https://github.com/operasoftware/opera-devtools-mcpWrote 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.
[](https://agentmods.dev/skills/operasoftware/opera-devtools-mcp/chrome-devtools)<a href="https://agentmods.dev/skills/operasoftware/opera-devtools-mcp/chrome-devtools"><img src="https://agentmods.dev/badge/skills/operasoftware/opera-devtools-mcp/chrome-devtools/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.
<a href="https://agentmods.dev/skills/operasoftware/opera-devtools-mcp/chrome-devtools"><img src="https://agentmods.dev/badge/skills/operasoftware/opera-devtools-mcp/chrome-devtools.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00055 | $0.00945 |
| Opus 5.5 | $0.00022 | $0.00378 |
| Sonnet 5.5 | $0.00011 | $0.00189 |
| Haiku 4.5 | $0.00006 | $0.00094 |
Grade A, and why
chrome-devtools 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 1mo 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.
This is a copy
88% identical to chrome-devtools — 13 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Core Concepts
Browser lifecycle: Browser starts automatically on first tool call using a persistent Chrome profile. Configure via CLI args in the MCP server configuration: npx chrome-devtools-mcp@latest --help.
Addional tooling can be enabled by providing the following flags:
- For extension tooling, use the
--categoryExtensionsflag. - For memory tooling, use the
--memoryDebuggingflag.
Page targeting: Page-scoped tools require a pageId parameter to target a specific page. Use list_pages to see available pages and their IDs (e.g. pageId: 1), or use the ID returned when creating a page with new_page.
Note: For evaluate_script, pageId is required when targeting pages. However, when --categoryExtensions is enabled, pageId is optional so you can pass serviceWorkerId instead to evaluate inside an extension background service worker.
Element interaction: Use take_snapshot to get page structure with element uids. Each element has a unique uid for interaction. If an element isn't found, take a fresh snapshot - the element may have been removed or the page changed.
Workflow Patterns
Before interacting with a page
- Navigate:
navigate_pageornew_page - Wait:
wait_forto ensure content is loaded if you know what you look for. - Snapshot:
take_snapshotwithpageIdto understand page structure - Interact: Use element
uids from snapshot forclick,fill, etc., passing the correspondingpageId.
Efficient data retrieval
- Use
filePathparameter for large outputs (screenshots, snapshots, traces) - Use pagination (
pageIdx,pageSize) and filtering (types) to minimize data - Set
includeSnapshot: falseon input actions unless you need updated page state
Tool selection
- Automation/interaction:
take_snapshot(text-based, faster, better for automation) - Visual inspection:
take_screenshot(when user needs to see visual state) - Additional details:
evaluate_scriptfor data not in accessibility tree
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.
- 1mo ago Changed · +1 lines b27f4b6d68f7
- 2mo ago First seen · 73 lines · 55 tokens per session scan A 9878a3260c5d
chrome-devtools is a skill published in the GitHub repository operasoftware/opera-devtools-mcp (16 stars, last pushed yesterday), licensed Apache-2.0. It adds 55 tokens to every session and 945 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 88% identical to chrome-devtools, differing in 13 lines, and is treated as a copy.
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