We build tools that depend on web search. Our research platforms run dozens of queries, pulling market data, competitor intelligence, and regulatory information from across the web. The quality of those search results directly determines the quality of the output.
We ended up going down a rabbit hole in a recent project and decided to do a deep dive on Claude search. It seemed to return better search results than calling the Brave API directly and left us wondering, why?
We built a test harness, ran 15 queries through both systems, and measured the differences.
The setup
We tested three categories of query, five each:
- General knowledge — straightforward supplement questions (magnesium benefits, vitamin D timing, ashwagandha dosage). Baseline queries where both systems should perform well.
- Brand intelligence — competitive analysis queries relevant to our work (UK DTC supplement brands, market sizing, competitor SWOT analysis). These are the queries our platform runs in production.
- UK regulatory — domain-specific, geography-specific queries (MHRA regulations, FCA open banking, HFSS impact on supplements). The hardest category — recent, niche, and jurisdiction-bound.
For each query we captured:
- Brave’s top 10 results (direct API call, country=GB)
- Claude’s cited URLs and the reformulated queries it actually searched for
- Brave’s results for Claude’s reformulated queries (to isolate whether differences came from query rewriting or result filtering)
- A local Ollama model’s query reformulations run through Brave (as a third comparison point)
The full test took roughly 16 minutes due to API rate limits.
The headline numbers
Overall, only 38% of Claude’s cited URLs appeared in Brave’s direct top-10 results for the same query. The majority of what Claude surfaces is different from what a direct API call returns.
Here is how it broke down by category:
General Knowledge: 22% overlap. Claude reformulated 60% of queries. On average, Claude surfaced 3.8 unique URLs per query that Brave didn’t return, while Brave had 7.8 unique URLs that Claude didn’t cite.
Brand Intelligence: 47% overlap. Claude reformulated 100% of queries. Claude surfaced 11.8 unique URLs per query vs Brave’s 3.0.
UK Regulatory: 44% overlap. Claude reformulated 100% of queries. Claude surfaced 10.4 unique URLs per query vs Brave’s 3.0.
Per-query detail
The averages tell one story. The individual queries tell a more interesting one. Below are selected results showing the URL breakdown for each query — how many were unique to Brave, unique to Claude, or shared by both.
General Knowledge
"What are the health benefits of magnesium supplements"Claude ██████████ 10 cited (1 search)
Brave ██████████ 10 results
Shared ████ 4 URLs in common (40%)
├── Claude unique: 6 (NIH, PubMed, MDPI, Harvard Nutrition)
└── Brave unique: 6 (BBC Good Food, UH Hospitals, BSW Health)
Reformulated queries:Claude → "magnesium supplements health benefits research 2024"
Ollama → "magnesium supplement health benefits"
"evidence-based benefits of magnesium supplementation"
"magnesium for sleep anxiety and heart health studies"
| Shared URLs | Claude-Only | Brave Only |
|---|---|---|
| ods.od.nih.gov — Office of Dietary Supplements | mdpi.com — Unlocking the Power of Magnesium: Systematic Review | healthline.com — What Are the Health Benefits of Magnesium? |
| webmd.com — Magnesium Supplements: Benefits, Dosage | healthline.com — Magnesium Supplements: Benefits and Side Effects | bbcgoodfood.com — 10 health benefits of magnesium |
| medicine.tufts.edu — Can Magnesium Supplements Improve Health? | pmc.ncbi.nlm.nih.gov — Magnesium and Human Health: Perspectives | uhhospitals.org — The Surprising Health Benefits of Magnesium |
| health.harvard.edu — What can magnesium do for you? | pmc.ncbi.nlm.nih.gov — Magnesium Matters: Comprehensive Review | houstonmethodist.org — Should You Be Taking Magnesium Supplements? |
| ods.od.nih.gov — Office of Dietary Supplements (Consumer) | lifeextension.com — 12 Health Benefits of Magnesium Supplements | |
| nutritionsource.hsph.harvard.edu — Magnesium | bswhealth.com — 9 key health benefits of magnesium |
"Difference between whey protein isolate and concentrate"Claude 0 cited (didn't search — answered from training data)
Brave ██████████ 10 results
Shared 0 URLs in common (0%)
└── Brave unique: 10
Reformulated queries:Claude → (no search triggered)
Ollama → "whey protein isolate vs concentrate differences"
"whey protein isolate vs concentrate pros and cons"
"what is the difference between whey protein isolate and concentrate"
| Shared URLs | Claude-Only | Brave Only |
|---|---|---|
| none | didn't search — answered from training data | healthline.com — Whey Protein Isolate vs Concentrate |
| theorganicproteincompany.co.uk — Isolate vs Concentrate Whey | ||
| myprotein.com — Impact Whey vs Impact Whey Isolate | ||
| health.com — Not All Whey Protein Is Equal | ||
| nakednutrition.com — Whey Protein Concentrate vs. Isolate | ||
| ascentprotein.com — Difference Between Isolate and Concentrate | ||
| hollandandbarrett.com — Whey protein isolate & concentrate | ||
| nutrabay.com — Whey Protein Isolate Vs. Concentrate | ||
| glanbianutritionals.com — Spot the Difference: Isolate vs Concentrate | ||
| theproteinworks.com — Whey Concentrate Vs Isolate |
"How does creatine monohydrate work"Claude 0 cited (didn't search — answered from training data)
Brave ██████████ 10 results
Shared 0 URLs in common (0%)
└── Brave unique: 10
Reformulated queries:Claude → (no search triggered)
Ollama → "creatine monohydrate mechanism of action how it works"
"how does creatine monohydrate increase muscle strength and performance"
"creatine monohydrate ATP regeneration process explained"
| none | didn't search — answered from training data | my.clevelandclinic.org — Creatine: What It Does, Benefits & Safety |
|---|---|---|
| healthline.com — Creatine 101: What Is It and What Does It Do? | ||
| blog.nasm.org — What Does Creatine Do & Why You Should Use It | ||
| mayoclinic.org — Creatine | ||
| menshealth.com — The Science Behind Creatine Monohydrate | ||
| pmc.ncbi.nlm.nih.gov — Creatine Supplementation for Muscle Growth | ||
| theproteinworks.com — What Is Creatine Monohydrate? | ||
| health.harvard.edu — What is creatine? Benefits and risks | ||
| bbc.com — Creatine: The supplement that boosts brainpower | ||
| pmc.ncbi.nlm.nih.gov — Creatine in Health and Disease |
Brand Intelligence
"UK protein powder market size and growth 2025"Claude ██████████ 10 cited (1 search)
Brave ██████████ 10 results
Shared ████████ 8 URLs in common (80%)
├── Claude unique: 2
└── Brave unique: 2
Reformulated queries:Claude → "UK protein powder market size growth 2025"
Ollama → "UK protein powder market size forecast 2025"
"UK sports nutrition market growth statistics 2025"
"protein supplements market analysis United Kingdom 2025"
| mordorintelligence.com — UK Protein Market Size & Growth to 2030 | gminsights.com — Protein Powder Market Size, Growth Outlook 2025–2034 | futuremarketinsights.com — Protein Powder Market Size & Trends 2025–2035 |
|---|---|---|
| reads.alibaba.com — The Booming Market of UK Protein Powder | mobilityforesights.com — UK Whey Protein Market Size and Forecasts 2031 | grandviewresearch.com — UK Protein Supplements Market Outlook, 2030 |
| sphericalinsights.com — UK Protein Supplements Market Size | ||
| grandviewresearch.com — Protein Supplements Market Size, Report 2033 | ||
| mordorintelligence.com — UK Whey Protein Market Size | ||
| verifiedmarketresearch.com — UK Protein Market Size and Forecast | ||
| sphericalinsights.com — Protein Powder Market Share, Forecast 2030 | ||
| factmr.com — Protein Supplements Market Share and Statistics |
"MyProtein competitor analysis strengths weaknesses"Claude ██████████████████████████████ 30 cited (3 searches)
Brave ██████████ 10 results
Shared █████████ 9 URLs in common (30%)
├── Claude unique: 21 (SWOT analyses, industry reports, niche reviews)
└── Brave unique: 1
Reformulated queries:Claude → "MyProtein competitors analysis 2024 2025"
"MyProtein strengths weaknesses SWOT analysis 2024"
"Optimum Nutrition Protein Works Bulk.com strengths weaknesses comparison 2024"
Ollama → "MyProtein competitors strengths and weaknesses analysis"
"best MyProtein alternatives comparison 2024 pros and cons"
"MyProtein market position vs competitors nutritional supplements"
| blog.osum.com — MyProtein SWOT Analysis Unveiled | tracxn.com — Myprotein 2025 Company Profile & Competitors | blog.osum.com — MyProtein’s Stronghold on Market Share |
|---|---|---|
| blog.osum.com — A Thorough MyProtein Market Analysis | salience.co.uk — 2025 Nutrition & Supplements Market Report | |
| blog.osum.com — The Strengths of MyProtein Revealed | ecdb.com — Myprotein Company & Revenue 2015–2027 | |
| craft.co — Top MyProtein Competitors and Alternatives | studycorgi.com — The Myprotein Company’s Analysis | |
| the5marketeerz.wordpress.com — SWOT & TOWS Analysis | theproteinbar.weebly.com — S.W.O.T Analysis | |
| the5marketeerz.wordpress.com — MyProtein Marketing Audit | openpr.com — Pure Whey Protein Market SWOT Analysis | |
| owler.com — Myprotein Inc’s Competitors, Revenue | bulk.com — INFORMED WHEY vs. ON Gold Standard | |
| similarweb.com — myprotein.com Traffic Analytics | which.co.uk — Best protein powders 2026 | |
| semrush.com — Top 6 myprotein.com Alternatives | muscletalk.co.uk — Best Whey Protein UK Reviews 2024 | |
| muscle-plus.co.uk — Top 10 Best Whey Protein Powders | ||
| uk.trustpilot.com — Optimum Nutrition Reviews | ||
| expertreviews.co.uk — Best protein powders for muscle gain 2024 |
"DTC supplement brand launch strategy UK market"Claude ████████████████████████████ 28 cited (3 searches)
Brave ██████████ 10 results
Shared █████ 5 URLs in common (18%)
├── Claude unique: 23 (regulatory guides, DTC playbooks, market reports)
└── Brave unique: 5
Reformulated queries:Claude → "DTC supplement brand launch strategy UK market 2026"
"UK supplement market regulations DTC brands 2026"
"UK consumer supplement buying behavior trends 2026"
Ollama → "DTC supplement brand launch strategy UK market case studies"
"how to launch a direct-to-consumer supplement brand in the UK regulations"
"UK DTC supplement marketing channels and customer acquisition strategies 2024"
| neramarketing.co.uk — Building a DTC Supplement Brand | vitamanufacture.co.uk — Electrolyte Hydration Supplements UK: 2026 | newhope.com — 5 tips for launching a DTC supplement brand |
|---|---|---|
| favoured.co.uk — Rise of Health & Wellness E-Commerce 2025 | bigblue.co — Top 10 DTC Brands to Follow 2026 | purebranding.com — The Six Costs of Entry for DTC Brands |
| champion-bio.com — Supplement Sales Channels 2025: DTC vs. Retail | blog.prontous.com — 17 Trending Supplement DTC Brands 2026 | awin.com — Health brings 143% sales uplift for DTC brands |
| thesocialshepherd.com — Top 13 DTC Agencies in the UK (2026) | shapeshifterdistribution.co.uk — Top Marketing Strategies 2026 | purebranding.com — Five Tips for Launching a DTC Supplement Brand |
| ecommercefastlane.com — Scaling Your DTC Brand With Supplements | food.gov.uk — Food supplements (FSA) | mmm-online.com — Pharma is moving toward DTC platforms |
| openborder.com — Charting the UK’s Supplement eCommerce Surge | ||
| hsis.org — Food Supplements Regulations | ||
| supplementfactoryuk.com — How Are Supplements Regulated in the UK? | ||
| foodcomplianceinternational.com — UK Food Compliance | ||
| foodmanufacture.co.uk — Top three trends in supplements 2026 | ||
| nutraceuticalbusinessreview.com — Trend predictions 2026: wellness growth | ||
| store.mintel.com — UK Vitamins and Supplements Market Report 2025 | ||
| euromonitor.com — Top Trends Shaping Consumer Health 2026 |
UK Regulatory
"FCA open banking UK latest updates 2025"Claude ██████████ 10 cited (1 search)
Brave ██████████ 10 results
Shared ████████ 8 URLs in common (80%)
├── Claude unique: 2
└── Brave unique: 2
Reformulated queries:Claude → "FCA open banking UK updates 2025"
Ollama → "FCA open banking UK regulatory updates 2025"
"UK open banking standards and compliance changes 2025"
"Financial Conduct Authority open banking consultation papers 2025"
| fca.org.uk — Open banking: a year of progress | fca.org.uk — Open banking and open finance | openbanking.org.uk — UK’s New Commercial Open Banking Scheme |
|---|---|---|
| fca.org.uk — Open banking and the FCA | regulationtomorrow.com — Open banking update | gov.uk — Joint response from the FCA and PSR |
| Shared URLs Claude-Only Brave Only fca.org.uk — Open banking: a year of progress fca.org.uk — Open banking and open finance openbanking.org.uk — UK’s New Commercial Open Banking Scheme fca.org.uk — Open banking and the FCA regulationtomorrow.com — Open banking update gov.uk — Joint response from the FCA and PSR fca.org.uk — FS25/4: Design of the Future Entity for UK open banking | ||
| fca.org.uk — Open banking and open finance in the UK | ||
| fca.org.uk — FCA announces partnership for open finance | ||
| fca.org.uk — FCA shares feedback on new standard setting body | ||
| openbankingexpo.com — FCA announces commercial VRP scheme 2025 | ||
| fca.org.uk — Open Banking and Open Finance (Research Note PDF) |
"UK food supplement labelling requirements EFSA health claims"Claude ████████████████████ 20 cited (2 searches)
Brave ██████████ 10 results
Shared ██████ 6 URLs in common (30%)
├── Claude unique: 14 (GB nutrition register, EFSA opinions, FSA guidance)
└── Brave unique: 4
Reformulated queries:Claude → "UK food supplement labelling requirements EFSA health claims 2024"
"UK Great Britain nutrition health claims register 2024"
Ollama → "UK food supplement labelling requirements EFSA health claims post-Brexit"
"site:gov.uk food supplements labelling regulations EFSA approved health claims"
"UK food supplement labelling legal requirements for EFSA authorised health claims 2024"
| hsis.org — Food Supplements Regulations | gov.uk — Nutrition legislation information sheet | assets.publishing.service.gov.uk — Technical guidance on nutrition labelling |
|---|---|---|
| assets.publishing.service.gov.uk — Food supplements legislation summary | gov.uk — Nutrition and health claims: guidance to compliance | pagb.co.uk — Food Information for Consumers Regulation guidance |
| sitruna.com — Food Supplements on Amazon UK: EFSA & Ingredients | efsa.europa.eu — Health claims (EFSA) | foodcomplianceinternational.com — UK Food Compliance |
| food.gov.uk — Food supplements (FSA) | food.ec.europa.eu — EU register of health claims | privatelabelsupplements.co.uk — Food Supplement Labelling guidance |
| mastermindtranslations.co.uk — Supplement Advertising & Labelling Rules | gov.uk — GB nutrition and health claims (NHC) register | |
| supplementfactoryuk.com — How Are Supplements Regulated in the UK? | assets.publishing.service.gov.uk — GB NHC register (PDF) | |
| legislation.gov.uk — Nutrition and Health Claims Amendment Regs 2024 | ||
| gov.uk — UK Nutrition and Health Claims Committee | ||
| asa.org.uk — Food: Health claims | ||
| leatherheadfood.com — UK nutrition and health claims |
"Stripe vs Adyen payment processing UK DTC ecommerce"Claude ████████████████████ 20 cited (2 searches)
Brave ██████████ 10 results
Shared █████ 5 URLs in common (25%)
├── Claude unique: 15 (comparison articles, fintech analyses, DTC case studies)
└── Brave unique: 5
Reformulated queries:Claude → "Stripe vs Adyen payment processing UK ecommerce comparison 2024"
"DTC direct consumer ecommerce payment processors UK 2026"
Ollama → "Stripe vs Adyen UK DTC ecommerce comparison"
"best payment gateway for UK direct to consumer ecommerce Stripe Adyen"
"Stripe and Adyen fees features UK ecommerce merchants"
| merchantsavvy.co.uk — Stripe Vs Adyen: Best For UK SMEs? | fintechwrapup.com — Deep Dive: Stripe vs. Adyen 2024 | seo.ai — Adyen vs Stripe: Key Differences |
|---|---|---|
| comparecardfees.co.uk — Stripe Vs Adyen: A Guide To Choosing | samboboev.medium.com — Stripe vs. Adyen: 2024 Performance | reddit.com/r/fintech — Honest pros/cons of Adyen and Stripe |
| noda.live — Adyen vs Stripe: Comparing Payment Solutions | business.bitso.com — Stripe vs. Adyen: performance in 2024 | reddit.com/r/vuejs — Best and cheapest payment Gateways? |
| chargeflow.io — Stripe vs Adyen: Reliable Comparison | samboboev.medium.com — Stripe vs. Adyen: Product Stacks | fitsmallbusiness.com — Adyen vs Stripe: Price & Features |
| spreedly.com — Stripe vs Adyen | finextra.com — Deep Dive: Stripe vs. Adyen 2024 | merchantsavvy.co.uk — Stripe Review 2025: UK Fees |
| uk.clover.com — Direct to consumer payment processing | ||
| spxcommerce.com — How the DTC Model Works 2026 | ||
| shopify.com/uk — Direct to Consumer: DTC Model 2026 | ||
| bigblue.co — Top 10 Direct-To-Consumer Brands 2026 | ||
| klaviyo.com/uk — What is a DTC business model? |
Query reformulation is the differentiator
The most interesting finding was about query reformulation. Claude rewrote 87% of queries before searching, and for Brand Intelligence and UK Regulatory categories, the reformulation rate was 100%.
These aren’t trivial rewrites. “Best UK supplement brands direct to consumer 2025” became two searches: “best UK supplement brands direct consumer 2025” and “direct consumer supplement brands UK 2025 online sales”. “UK food supplement labelling requirements EFSA health claims” became “UK food supplement labelling requirements EFSA health claims 2024” and “UK Great Britain nutrition health claims register 2024”.
Claude adds temporal specificity (appending years), decomposes compound questions into focused sub-queries, and varies terminology to widen coverage. This is the behaviour of a skilled researcher, not a keyword matcher.
To test whether the value came from reformulation or from Claude’s result filtering, we ran Claude’s reformulated queries back through Brave directly. The overlap between those Brave-reformulated results and Claude’s cited URLs was 44% — higher than the 38% direct overlap, but still showing that Claude’s selection layer adds value beyond just rewriting queries.
The Ollama comparison
We also ran a local Qwen 3.5 model (35B, via Ollama) as a query reformulator, feeding its rewrites into Brave. This produced a 44% overlap with Claude’s citations — roughly the same as running Claude’s own reformulated queries through Brave.
This suggests that a meaningful chunk of Claude’s advantage comes from query reformulation, which a smaller local model can approximate. But Claude still surfaces URLs that neither Brave nor Ollama-reformulated Brave finds, indicating its search and filtering pipeline does additional work beyond reformulation.
The Trust Problem
So this is just two system. Two systems, searching the same web, return mostly different sources. Different URLs. Different authorities. Different versions of the truth.
And we just accept that.
We've built an entire AI ecosystem on top of open web sources, but there's no consensus on what we actually trust. Marketing managers race to get content ranking for GTM visibility. SEO teams optimise for the algorithm, not for accuracy. The result is a web full of content that's designed to be found, not to be right.
That was tolerable when humans were reading the results and applying judgement. But now AI agents are consuming these sources, synthesising them, and presenting conclusions as if they're fact. The search results aren't just informing people anymore, they're training the reasoning layer.
When Claude reformulates a query and selects 10 sources from hundreds of candidates, what's the trust model? When it cites a blog post from a supplement company alongside an NIH study, are those equivalent? Who decides?
Right now, nobody. There's no standard. No verification. No trust layer.
Perhaps we need one.
Think about what SSL did for ecommerce. Before SSL certificates, you had no way to verify that a website was who it claimed to be. The certificate didn't guarantee the product was good but it did guarantee the connection was secure and the identity was verified. It created a baseline of trust that made commerce possible.
AI search needs something similar. A verified, regulated standard that sources must meet to be included in AI-consumed search results at all. Not a quality judgement, a trust floor. Is this source who it claims to be? Is the content attributed? Is there an accountable entity behind it? Has it met a minimum bar for transparency?
Without that, we're building the intelligence layer of the future on foundations nobody has bothered to verify.
Methodology notes
All data was collected on 9 March 2026. Claude model: claude-sonnet-4-20250514. Brave API: Web Search v1 with country=GB. Ollama model: Qwen 3.5 35B (A3B quantisation). URL comparison normalised for protocol, www prefix, trailing slashes, and UTM parameters.
Overlap rate is calculated as the percentage of Claude’s cited URLs that also appear in Brave’s top 10. “Claude unique” and “Brave unique” counts refer to URLs surfaced by one system but not the other for the same query.
