SEO · AGENT SKILLS · 6 MIN
Claude SEO vs Semrush: what a free audit replaces, and what it does not
One is a command you type in a terminal and get a prioritized audit from. The other is the closest thing the industry has to an SEO operating system: keyword databases, rank tracking, backlinks, competitive intelligence, and reporting, all in one subscription. Comparing Claude SEO and Semrush as if they were the same product class is the mistake almost everyone makes before they look at the actual jobs. The useful question is which jobs each one finishes, and which of those jobs you are paying for.
The cost gap makes the comparison feel lopsided: a free MIT skill against a platform that starts at $117 per month billed annually. But the free tool is not a smaller version of the paid one. It does a different thing, and knowing where the line falls saves you either a wasted subscription or a technical audit your platform will not run.
Most readers should pick Semrush. Day-to-day SEO work is mostly recurring: tracking rankings, watching backlinks, researching keywords, and reporting to someone who does not open a terminal. Claude SEO does none of that. It wins the one job it was built for, a deep technical and AI-search audit of a site, and it does that job for the cost of API tokens. Buy Semrush for the platform work and keep Claude SEO for the audit, or defer the subscription until you need the data layer.
The comparison at a glance
| Decision factor | Claude SEO | Semrush |
|---|---|---|
| Cost | Free MIT skill; you pay API tokens per audit, roughly $6 per site in our runs | From $117/mo billed annually (Pro); Guru $250/mo; Business $500/mo; Semrush One $199/mo |
| Data it owns | None; it reads public sources and crawls on demand | A keyword database of 25 billion keywords across more than 140 countries, plus a backlink index and a site crawler with 140-plus checks |
| Ongoing monitoring | Point-in-time audits; no UI and no stored history | Daily position tracking, historical data on higher tiers, and scheduled crawls |
| Audit depth | Evidence-linked findings with dependencies and an explicit check for whether a fix worked | A technical crawler that flags issues across a large rule set, aimed at monitoring rather than a written action plan |
| AI search readiness | Scores pages for citability by AI answer engines, checks llms.txt and the structured data LLMs cite | Tracks AI visibility alongside traditional search, from a dashboard angle |
| Who can use it | Developers and SEO practitioners already in Claude Code | Any marketer, with dashboards, integrations, and client-ready reporting |
| Integrations | Claude Code, Google Search Console, DataForSEO, Firecrawl, Lighthouse | Google Analytics, Google Search Console, WordPress, Zapier, Slack, HubSpot, Salesforce, Looker Studio |
Neither tool is a complete answer, and the table shows why. Claude SEO has no database to stand on. Semrush has no terminal command that hands you a written, falsifiable fix list. The overlap is the site crawler, and even there the output shapes differ.
Factor by factor: who wins and why
Upfront cost: Claude SEO. The skill is free and MIT licensed, and our full-site audits on sites of 90 to 170 pages ran about five minutes and roughly six dollars each in API tokens. Semrush starts at $117 per month billed annually. For a one-off audit on a developer's machine, there is no contest.
Data breadth: Semrush. This is not close, and it is the reason the subscription exists. Semrush spans keyword research, competitive analysis, link building, and paid-ad intelligence on a database of 25 billion keywords across more than 140 countries, founded in 2008 and used by more than 10 million people. Claude SEO has no proprietary dataset; it reads what is public and crawls the site in front of it.
Ongoing monitoring and history: Semrush. Position tracking runs daily, and historical data and scheduled audits sit on the higher tiers. Claude SEO produces a point-in-time report with no UI and no storage beyond what you keep. If your question is "how did we move this month," Claude SEO cannot answer it, because it did not record last month.
Audit depth per run: Claude SEO. Our Claude SEO teardown found real defects the deploy pipeline had shipped for weeks, and every finding carried the evidence behind it, its dependencies, and a check for whether the fix worked. Semrush's site audit covers a large rule set and is built for monitoring many sites, but it reports issues rather than arguing a priority order.
AI search readiness: Claude SEO. The skill scores content for citability by AI answer engines, checks for self-contained answer blocks and llms.txt, and grades the structured data that makes a model cite you rather than a competitor. Semrush tracks AI visibility across a market, which is a measurement job. The two are complementary, and the skill is the more useful of them when the question is "what do I change on this page."
Team access and reporting: Semrush. Dashboards, eight listed integrations including Google Analytics and WordPress, and white-label reporting on the Business tier. Claude SEO is terminal-only, which is a feature for a developer and a wall for a marketing team that needs something presentable on a Friday.
Which should you pick
An in-house SEO lead with a site to grow and people to report to. Buy Semrush. Rank tracking, backlink monitoring, and keyword research are recurring needs, and the platform covers all three plus the reporting that keeps the budget approved.
A developer team already working in Claude Code that needs a technical audit. Use Claude SEO. Install the skill, run it against your own domain, and work the fix list. You will learn more about your site in one run than a month of dashboard-watching, and it costs token money rather than a seat.
An agency running several client sites. Use both, and be deliberate about which one touches a client. Run Claude SEO for the deep technical and AI-search audit, and Semrush for the monthly tracking and client-facing report. One caveat we found the hard way: the skill appends its author's community links to major deliverables, so strip that footer before anything client-facing leaves the building.
One thing neither tool does is tell you whether a fix moved the needle. Claude SEO gives you a falsifiability check and a leading indicator to watch; Semrush gives you the trend line after the fact. Pair the audit with the tracking and you have both halves, which is the honest answer for most teams paying for one.
The Semrush side of this comparison draws on the vendor's published documentation, its pricing page, and our directory assessment; we have not run it inside this comparison. The Claude SEO numbers come from audits we ran on our own production site.
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