Short version: if your firm needs broad, general-purpose legal AI that many people use across many matter types, buy a platform like Harvey, Spellbook, or CoCounsel. If you have one or two specific, high-volume workflows quietly eating hours every week — and you would rather own the fix than rent a seat for every user forever — build a bespoke agent. Brightline Labs builds that agent in about two weeks, for a fixed fee, and hands you the source code. The rest of this piece is just how to tell which one you are.
The two models, in one breath
A legal-AI platform is a general-purpose product that thousands of firms share. You license access, you pay per seat per year, and you adapt your process to fit the tool. A bespoke agent is the opposite: one narrow module built around your exact workflow, your templates, and your review standards — paid for once, delivered to your GitHub, and yours to keep. Neither is inherently better. They are different shapes for different jobs.
And the platforms are genuinely good. Harvey and Legora have raised at multibillion-dollar valuations, and Thomson Reuters’ CoCounsel is mature and widely deployed. This is not a “platforms are bad” argument. It is a “platforms are the wrong shape for some jobs” argument.
When buying the platform is the right call
Reach for Harvey, Spellbook, CoCounsel, or a similar product when:
- You need broad coverage. Research, review, summarization, and drafting across many practice areas, rather than one deep workflow.
- You have many general users. Lots of people each need day-to-day AI assistance, and per-seat pricing pencils out.
- You want it live this week. Zero build effort, and you are comfortable adapting your process to the product.
- Ownership is not a requirement. You do not need the source code or deployment inside your own perimeter.
When a bespoke agent wins
Build instead when:
- One workflow dominates the pain. Deposition transcripts into issue outlines, intake into drafted matters, billable-time reconstruction, document intake into workpapers.
- It has to follow your firm. Your clause library, your templates, your review checklist — not a generic default.
- You are done renting seats. You would rather pay once and own the asset than renew a per-seat license every year.
- Client-data control matters. You want firm-local deployment, explicit allowlists, and no data used for training.
- You want it maintainable. Software any competent developer can extend, with no vendor holding your workflow hostage.
The ownership math
A per-seat platform is a permanent line item: every paralegal, associate, and partner who touches it is a recurring cost, every year, and at the end of any year you own nothing. A bespoke build inverts that. You pay a fixed fee once, the source code lands in your GitHub, and your seat license is a repository. Inference runs pay-as-you-go on your own keys. For a firm doing the same costly workflow hundreds of times a year, the bespoke build usually costs less over three years than the subscription — and you end with an asset instead of a cancelled contract.
How Brightline fits
We do not compete with Harvey or CoCounsel head-on; we build the narrow, owned agent a platform handles only generically. Plenty of firms run both. Every engagement starts the same way: a 30-minute call where we work out, honestly, whether custom AI is even the right tool — and if an off-the-shelf platform would serve you better, we say so. If it is the right tool, we scope it, fix the price, build it in about two weeks, and hand over the code. Book a 30-minute bottleneck audit if you want to find out which side of this line your firm is on.
