Opinion Lens

AI that shows its work.

Opinion Lens is Annlex's primary verification layer. This set of tools allows you to efficiently interact with a single court opinion. Every summary, brief, and answer is drawn from that opinion's text and nothing else. With Opinion Lens, you can verify the accuracy of any AI-generated statement with ease.

Open any case and you'll find the Opinion Lens strip above the text. Four tools, two kinds.

Tools that locate

Entity index, Key Passages, and Ask AI open beside the opinion. The text never leaves the screen, and the passage an answer rests on lights up in place.

Tools that produce

Summary and Case Brief open in a full reading view and download as a formatted document. These are things you take away with you.

01Free · no account

Entity index

Before any AI touches the page, Opinion Lens reads the opinion in your browser and pulls out every case cited, judge named, statute invoked, and reporter citation.

Pick one and the opinion scrolls to it. This is the fastest way to answer what is this opinion arguing with? — and it costs nothing, because nothing leaves your machine.

Press Ctrl Shift F to open it anywhere.

Opinion of the Court

1This case presents the question whether the Government conducts a search under the Fourth Amendment when it accesses historical cell phone records that provide a comprehensive chronicle of the user's past movements.

2The Government contends that the third-party doctrine governs, because the records were held by the wireless carriers rather than by the defendant himself.

3We decline to extend the third-party doctrine to this novel context. There is a world of difference between the limited types of personal information addressed in our earlier cases and the exhaustive chronicle of location information casually collected by wireless carriers today.

4The Government's acquisition of the cell-site records was a search. The Government must generally obtain a warrant supported by probable cause before acquiring such records.

5Our decision today is a narrow one. We do not express a view on real-time cell-site location information, tower dumps, or conventional surveillance techniques.

02

Key Passages

Key Passages finds the question presented, the rule, the holding, the dispositive facts, and any express limitation — and tells you which paragraph each one lives in.

Hover a result and the paragraph highlights in the opinion beside it. Nothing is paraphrased away from its source. If the model says the holding is at ¶ 4, you can go look at ¶ 4.

Opinion of the Court

1This case presents the question whether the Government conducts a search under the Fourth Amendment when it accesses historical cell phone records that provide a comprehensive chronicle of the user's past movements.

2The Government contends that the third-party doctrine governs, because the records were held by the wireless carriers rather than by the defendant himself.

3We decline to extend the third-party doctrine to this novel context. There is a world of difference between the limited types of personal information addressed in our earlier cases and the exhaustive chronicle of location information casually collected by wireless carriers today.

4The Government's acquisition of the cell-site records was a search. The Government must generally obtain a warrant supported by probable cause before acquiring such records.

5Our decision today is a narrow one. We do not express a view on real-time cell-site location information, tower dumps, or conventional surveillance techniques.

Opinion LensKey Passages

Hover a passage to locate it.

03Summary saved · Brief on request

Summary and Case Brief

Summary is a plain-English account of what the court decided and why. It's generated once per opinion and stored, so it opens instantly.

Case Brief is the IRAC-format brief a law student or an associate would write, with quoted support. It's generated when you ask for it and streams as it's written. Both download as a formatted document.

Neither consults outside law. If a proposition isn't in this opinion, it isn't in the brief.

Opinion Lens
Summary
Carpenter v. United States, 585 U.S. 296 (2018)
Saved · instant Download

The Court held that acquiring historical cell-site location information is a Fourth Amendment search, and generally requires a warrant.

Roberts, C.J., declined to extend the third-party doctrine, reasoning that the breadth and retrospective reach of location data distinguish it from the business records in Smith and Miller.

The decision is expressly narrow. Real-time CSLI, tower dumps, and conventional surveillance were all reserved.

Generated from the full text of this opinion. Nothing outside it was consulted.

“The cornerstone of credibility is falsifiability.”

(h/t Karl Popper)
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Ask AI

Ask a question in your own words. The answer is grounded in this opinion's text alone, and every answer offers to show you the paragraph it rests on.

When the opinion doesn't answer your question, Annlex says so. That refusal is the feature. A model that always has an answer is a model that will eventually invent one.

Three questions per opinion without an account. A free account removes the limit.

Opinion of the Court

1This case presents the question whether the Government conducts a search under the Fourth Amendment when it accesses historical cell phone records that provide a comprehensive chronicle of the user's past movements.

2The Government contends that the third-party doctrine governs, because the records were held by the wireless carriers rather than by the defendant himself.

3We decline to extend the third-party doctrine to this novel context. There is a world of difference between the limited types of personal information addressed in our earlier cases and the exhaustive chronicle of location information casually collected by wireless carriers today.

4The Government's acquisition of the cell-site records was a search. The Government must generally obtain a warrant supported by probable cause before acquiring such records.

5Our decision today is a narrow one. We do not express a view on real-time cell-site location information, tower dumps, or conventional surveillance techniques.

Opinion LensAsk AI3 of 3 free

Answers come only from this opinion's text. If it isn't in the opinion, Annlex says so rather than guessing.

Why the text stays on screen

Most AI legal tools ask you to trust a summary. Opinion Lens is built on the opposite assumption: a claim about a case is only as good as the passage it came from, and that passage should be one glance away.

So the generative tools never cover the opinion. They sit beside it, and they point. You are always one hover from the sentence the machine read.