May known (for both party) implicit limitations change the scope of a contract?
<p><a href="https://law.stackexchange.com/questions/17849/vague-clause-in-employment-contract">This question</a> has an employee with two different employers, each employer fully knowing the situation, and each contract has a clause telling that all the software produced by the employee (even outside work hours) belongs to each of the employer.</p>

<p>Now, the employee wondered if he had signed himself in a position were he could be forced to give one of his employers something that the employee did not own (the code he did working for the other employer).</p>

<p>Common sense would tell that each of the employers know that the employee does not own the code he is producing for the other employer, so they cannot ask him to give something that is not his to give. And since they knew about this limitation at the moment of signing/giving permission to get a second job, does that mind that they lose their right to pretend ownership of the other employer's code? Is this situation codified in some law term?</p>

<p>It is a principle of contract law that, where there <em>is</em> a written contract, that it is definitive as to the intent of the parties. If the plain English meaning is X and one party maintains that it means X while the other maintains it means Y then, absent evidence of fraud, coercion or statutory interference (e.g. consumer protection law), <strong>it means X!</strong></p>

<p>The employee may well have put themselves in a position where they cannot meet their obligations under both contracts and will be required to breach (at least) one of them. This can leave them liable for damages - a wise employee would therefore choose to breach the one that leaves them liable for the least amount of damages.</p>

<p>Alternatively, it could be argued that the second contract entered into was void for impossibility i.e. it is impossible to <em>legally</em> fulfill the contract. However, this does not get the employee off the hook as they are now liable for damages for the tort of misrepresentation i.e. they said they could do something they couldn't.</p>

<p>In both cases, the employee could argue that damages should be mitigated or nominal given that the principal(s) was aware of the conflict between the contracts. Who knows? Such an argument may even be successful.</p>

<p>Ultimately, it will turn on the specifics of each contract. For the example you have given, assuming that the clauses in each contract are the same, it is not actually a problem. The clause quoted says:</p>

<blockquote>
  <p>Any server development programming created by you during your employment by [redacted employer name] automatically belongs to [redacted employer name]</p>
</blockquote>

<p>There is nothing in this that requires <em>sole</em> ownership and the employee is able to comply by giving the principals joint ownership of the IP. This is possibly not what they wanted but it <em>is</em> what they said.</p>

contract-law