Invention Assignment Agreements: What Engineers Need to Know

Almost every tech company employment agreement includes an invention assignment provision. It's so standard that most engineers sign it without a second thought. That's a mistake, especially if you have side projects, open-source work, or ideas you're developing outside of work. Here's how invention assignment actually works and where the limits are.

What Invention Assignment Captures

Invention assignment provisions transfer ownership of intellectual property from you to your employer. The scope of what gets transferred is typically defined broadly in the agreement — covering inventions, discoveries, improvements, processes, formulas, designs, trade secrets, and often copyrightable works.

The word "inventions" in this context is broader than the common understanding. You don't need to have filed a patent for something to be an "invention" under these agreements. An invention is typically defined to include anything you conceive, develop, discover, or work on — whether or not it's patentable, whether or not it's ever disclosed, and whether or not it becomes commercially valuable.

This is different from copyright, which applies to creative expression. Copyright in work created within the scope of employment is typically a "work made for hire" owned by the employer under copyright law. Invention assignment captures the patent rights. Together, these provisions give employers broad ownership of both creative and functional intellectual property developed during employment.

Conceived or Reduced to Practice

The standard trigger for invention assignment is "conceived or reduced to practice during the term of employment." Understanding both parts matters:

Conception happens when you have the complete idea for an invention — you've thought it through sufficiently to enable someone skilled in the field to build it. You don't need to have written any code or built a prototype. If you sketch out a detailed technical approach in a notebook while sitting on your couch on a Sunday evening, conception may have occurred — and the question of assignment turns on whether that idea falls within the scope of the assignment clause.

Reduction to practice means you've actually implemented the invention — you've built a working prototype, written the functional code, or otherwise demonstrated that the concept works. This can happen long after conception.

Both are captured. The assignment clause typically doesn't require that you've reduced anything to practice — conception alone, within the scope of the employer's business, is often sufficient.

The Prior Inventions Schedule: Use It

Every invention assignment agreement includes an exhibit — sometimes called the Prior Inventions Schedule, Exhibit A, or similar — where you list any inventions, works, or projects you want to exclude from the assignment. Before you sign anything, this is the single most important action you can take.

List every personal project, open-source contribution, software tool, creative work, app, or intellectual property concept you own and want to retain. Include the name, approximate date, and a brief description. You don't need to reveal implementation details — just enough to identify the item and put the employer on notice.

What you don't list, and that later becomes relevant to the employer's business, is at serious risk of being treated as assigned property. The prior inventions schedule is not optional, even though it's presented as a blank page that most people leave empty.

If you have significant prior IP — a startup project, a side business, a patent application — consult an attorney before you sign to make sure the exclusion is properly structured.

State Law Protections for Personal Projects

Several states have enacted statutes that limit invention assignment. These laws typically prevent employers from requiring assignment of inventions that employees developed entirely on their own time, without using employer resources, and that don't relate to the employer's current or reasonably anticipated business.

The states with these protections include California (Labor Code § 2870), Delaware, Illinois (765 ILCS 1060/2), Minnesota (Minn. Stat. § 181.78), Washington (RCW 49.44.140), and North Carolina. The specifics vary by state, but the core principle is consistent: your time, your resources, unrelated to the employer's business = your invention.

The challenge is the "relates to the employer's business" carve-out. If you work at a cloud infrastructure company and you're building a database tool on the weekends, there's a colorable argument that your project relates to the employer's business. The statutory protections are real but don't cover everything.

Copyright and Work-for-Hire

Invention assignment handles patents. Copyright raises a separate but related issue.

Under copyright law, a "work made for hire" — a creative work made by an employee within the scope of their employment — is automatically owned by the employer. This applies to software you write at work, in many cases.

Employment agreements typically reinforce this by explicitly assigning all copyrightable works created during employment and relating to the employer's business. The combination of invention assignment (for patents) and copyright assignment or work-for-hire provisions (for creative works) gives the employer comprehensive IP ownership of your work during employment.

What they can't own: your general skills, knowledge, and professional expertise. The rule of thumb is "you own your brain." An employer can own the specific code you write at work; they cannot prevent you from being a skilled software engineer who knows how to build similar systems using your general knowledge.

Protecting Your Side Project

If you have a side project you want to protect:

1. Fill out the prior inventions schedule before signing. List the project specifically.
2. Use your own equipment and time exclusively. Never use a work laptop, work phone, or work hours to work on personal projects.
3. Don't use work resources — no work email, no work accounts, no work infrastructure.
4. Make it clearly distinct from your employer's business area if possible.
5. Document the timeline — show conception and development dates that precede employment if the project predates your job.

If there's overlap between your project and your employer's business, consider having an attorney review whether the state law protection applies before signing the assignment agreement.

The Bottom Line

Invention assignment agreements can capture more than most engineers realize — including weekend projects that happen to relate to your employer's technology area. Before signing, paste your invention assignment agreement into dott.legal for a free AI risk analysis that evaluates the assignment scope and flags any clauses that might affect your personal IP. For situations involving valuable prior IP or a startup project, attorney-validated review is $349 with 24-hour turnaround.