safari-browser

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name: safari-browser description: General-purpose browser automation via the safari-mcp-stp MCP server (Safari Technology Preview) — navigate URLs, read page content, click/type/fill forms, take screenshots, and debug page loads via network requests and console messages. Reach for this any time an actual browser would settle the question, not just when the user says "browser": checking whether a URL or link is reachable/valid, verifying a UI or frontend change actually renders and works before reporting it done, reproducing a bug the user describes seeing on a page, reading/scraping a live webpage, filling out or submitting a form, or debugging a blank page, failed request, redirect loop, or JS console error.

Safari Browser Skill

Drives Safari (via the safari-mcp-stp MCP server / WebKit Inspector) for general browser automation and for debugging why a page isn't loading or behaving right. Every claim and code path below was exercised directly against live pages (example.com, httpbin.org, a nonexistent domain) in this session — not inferred from docs.

Tool inventory

Tool	Purpose
list_tabs / create_tab / switch_tab / close_tab	Tab lifecycle
navigate_to_url	Load a URL in a tab (auto-creates one if none open)
page_info	Current URL, title, load state — the fast way to sanity-check where you are
get_page_content	Preferred way to read a page — WebKit text extraction, returns uid=N node references
page_interactions	Batched click/type/scroll/hover/selectMenuItem/keyPress, by node uid or text find-in-page
evaluate_javascript	Run JS; use $uid(N) to reference nodes from get_page_content. Last resort for reading — prefer get_page_content
screenshot	PNG saved to disk (path returned, never inline base64)
set_viewport_size / set_emulated_media	Window size / CSS media emulation
list_network_requests / get_network_request	Request list (filterable by method/status/URL substring) and full detail (headers, body, timing) for one request
browser_console_messages	Buffered console logs (debug/info/warn/error), drains the buffer by default
browser_dialogs	List/accept/dismiss JS alert/confirm/prompt
wait_for_navigation	Block until in-flight navigation finishes

If the MCP tools aren't responding

safari-mcp-stp needs Safari Technology Preview actually running to have anything to attach to. If a call to one of the tools above errors out or times out as if the server were offline, launch the app with the Bash tool, then retry the same MCP call:

open "/Applications/Safari Technology Preview.app"

The path contains a space, so it must be double-quoted (not backslash-escaped) — this is a plain open invocation, not an MCP tool call. Give the app a moment to finish launching before retrying; if the first retry still fails, the MCP server itself (not just the app) may need attention — say so rather than silently giving up.

Standard workflow

create_tab()                         # bare — don't pass url yet
set_viewport_size(1440, 2200)        # ALWAYS, even for a one-shot page read — see "Viewport" below
navigate_to_url(url)                 # now load the page
get_page_content()                   # read; note the uid=N on elements you need
page_interactions([...])             # click/type using those uids, batched
get_page_content()                   # re-read if the diff wasn't enough context
close_tab(handle)                    # clean up when done

Reach for evaluate_javascript or screenshot only when text extraction can't express what you need (a computed value, visual layout, a chart). get_page_content is cheaper and more reliable for reading.

Viewport — always set it, even for a quick one-off lookup

The default viewport is cramped (measured 1024×641 via window.innerWidth/innerHeight on a fresh tab) — small enough that responsive layouts render in a mobile/tablet breakpoint you probably don't want. This is not an optional step for "complex" tasks — set it on every session, including a single-page read like "check the weather at this URL." Skipping it for a "basic" request is exactly how it gets skipped. Call set_viewport_size right after opening the first tab, before navigating anywhere:

set_viewport_size(width: 1440, height: 2200)

1440×2200 is the preferred size for this project — tall enough to capture most pages (including long dashboards and stat pages) without scrolling. This is a browser-window-level setting, not per-tab — verified by creating a second tab after setting it and finding the new tab already at the wider size. Set it once per session, before your first navigate_to_url or create_tab(url: ...). Note the effective innerHeight will be somewhat less than what you request (browser chrome eats ~130–200px in testing at this size) — that's normal, not a bug.

Debugging a URL that won't load

This is the part that isn't obvious from the tool descriptions: navigate_to_url does not error or throw on a failed load. DNS failures, unreachable hosts, etc. all "succeed" as a tool call and silently return Safari's own error page as content. Confirmed by navigating to a nonexistent domain:

navigate_to_url("https://this-domain-does-not-exist-abc123xyz.invalid")
→ {"content": "root\n\t'Safari Can't Find the Server'\n\t...", "url": "safari-resource:/ErrorPage.html", "title": ""}

Detect a failed load with page_info, not the navigation result. page_info after a failed navigation reliably reports:

{"title": "Failed to open page", "url": "https://this-domain-does-not-exist-abc123xyz.invalid/"}

page_info.title === "Failed to open page" is the check. Don't match on URL — get_page_content's reported url flips to the internal safari-resource:/ErrorPage.html, but page_info's url field usefully keeps the original requested address.

For loads that "succeed" but render wrong (blank page, error banner, wrong content), work through these in order:

1. page_info — confirm you're actually on the URL/title you expect.
2. list_network_requests (optionally filter: {status_min: 400}) — find failed/redirected requests. Each entry has method, status, mime type, timing.
3. get_network_request(request_id) — full headers + response body for one request from that list. This is how you see an API's actual error payload, not just its status code.
4. browser_console_messages — JS errors and browser-logged resource failures (e.g. resource 404s auto-log as "Failed to load resource: the server responded with a status of 404 ()" at level: "error", no explicit console.error call needed).
5. screenshot — only once the above hasn't explained it; confirms what it looks like, not why.

Saving a page as clean markdown

get_page_content(format: "markdown", savePath: ...) looks like it writes ready-to-use markdown to disk. It doesn't, out of the box — verified against guide.macports.org and code.claude.com/docs:

• savePath writes the whole JSON response envelope, not just the extracted text. The file ends up as {"url": "...", "content": "...", "format": "markdown", "title": "..."} with the real newlines escaped as \n and slashes as \/. Always post-process: parse the file as JSON and write out just the content field.

  import json
  with open(path) as f:
      data = json.load(f)
  with open(path, 'w') as f:
      f.write(data['content'])
  

• maxWordsPerParagraph defaults to 15 and silently truncates almost every paragraph with …. This is the single biggest cause of "the markdown looks broken" — full sentences get chopped mid-clause. For a save-to-file task (as opposed to a quick skim), set it high (300–500+) so paragraphs come through intact.

• The extraction is not scoped to the article body. It includes the full page chrome — sidebar nav, header, footer, cookie/legal links, "was this helpful" widgets, chat-assistant boilerplate. Expect to manually strip this after fetching; there's no tool option to exclude it.

• HTML <table>s do not become markdown pipe tables. They flatten into a loose sequence of cell text with no | or row structure. If the page has a real table you want preserved, reconstruct it by hand from the flattened cells — don't expect the raw output to be usable as-is.

• Don't trust a site's visible nav links to predict real page URLs. On guide.macports.org, the left-nav <a> tags pointed at paths like /2, /3 that 404'd — the actual per-section pages lived under /chunked/<slug>.html, discoverable only by loading /chunked/index.html and reading its link list. Separately, the bare root URL (/) rendered as the entire multi-hundred-KB guide in one long scroll (contentSize height in the 100,000px+ range), not just its first visual section — check the reported contentSize before assuming a page is scoped to what its title suggests.

• Don't use this to bulk-mirror an entire multi-page work (a whole docs site, a whole book/guide) into a pile of local files. Fetching and saving one bounded page (or a couple, for a demo) is a normal dev-reference task; mechanically walking every section of something like a full project guide and writing out the complete text is reproducing the whole copyrighted work and should be avoided even when the source is free to read online. If a user wants a full local copy of a multi-page guide, point them at the site's own bulk-download option (single-page view, EPUB/PDF export) instead of reconstructing it page-by-page.

PDFs specifically

Tested against a .pdf URL loaded directly in Safari's built-in PDF viewer (a slide-deck-style investor presentation):

• navigate_to_url alone returns empty content for a PDF. Unlike HTML pages, the initial navigation result doesn't carry extracted text. Always follow up with an explicit get_page_content call.
• Once called explicitly, extraction worked well and pulled the complete document text with no truncation — PDF text tends to come as short fragments (slide bullets, captions) that don't hit the maxWordsPerParagraph ceiling the way HTML prose does. Still worth setting it high defensively if the PDF has dense paragraphs (e.g. a contract or report rather than slides).
• format: "markdown" and format: "text" return the same thing for a PDF — no # headers, no **bold**, no real structure. WebKit's PDF text layer has no DOM/semantic tags for a markdown formatter to hang structure on, so a PDF "converted to markdown" is really just plain text saved with a .md extension. Don't expect heading/table reconstruction the way you might manually do for an HTML page.
• No page chrome to strip (no nav/footer/sidebar) — that HTML-specific gotcha doesn't apply here.
• The savePath JSON-envelope issue above applies the same way to PDFs.

Gotchas

• browser_console_messages clears on read by default. clear defaults to true, so a call drains the buffer — a second call (even with a different level_filter) right after will come back empty. If you need to inspect the same batch multiple ways, pass clear: false on the read(s) you don't want to be final, and let the last one clear.
• list_network_requests misses the navigation triggered by create_tab's url argument. Requests only start accumulating partway through that first load — tested empty (count: 0) immediately after create_tab(url: ...) even though the page rendered fully. If you need the full request list for a page's initial load, create_tab() bare, then navigate_to_url() to it — the buffer captures navigations that happen after the tab exists.
• get_page_content's node uids are call-scoped — they come from the most recent get_page_content/page_interactions response. Re-fetch content before reusing a uid from an older read.
• Screenshots are files, not inline data. The tool returns a path; Read that path to actually view it.
• page_interactions batches — pass the whole sequence of clicks/types in one call rather than one call per step; it runs them with a 400ms settle between each and returns a single diff (or full text if >50% of the page changed).