A development harness over the code of the project you are standing in.
Developer mode is OSPal working on a codebase, in the style of Claude Code, Codex or OpenCode. It has no subtypes and no target: what particularizes it is the project you launch it from and the material you keep under ~/.ospal/developer/. It reads before it writes, keeps changes small, follows the conventions already in the repository and leaves version control to you.
OSPal is not one assistant with four settings. Each mode loads its own system prompt, its own set of tools and its own folder of skills, so the run is shaped for the work you are actually doing.
The system prompt is per platform, like the Basic one, and it adds the working rules of a development harness: read a file before editing it, keep the change minimal, verify it with whatever the project already provides, and never commit, push or rewrite history on its own.
message.send, shell.exec, script.run and skill.use. The editing goes through the shell and the scripts, which means every change passes through an approval you can read before it happens.
~/.ospal/developer/RULES.md holds your personal directives and travels in the system prompt, so it holds for the whole conversation and survives an automatic compaction. The skills of the mode live in ~/.ospal/developer/skills/.
cd /path/to/your/project
ospal --developer
ospal -dev
ospal -dev --skills-list-dev is the short alias. At startup OSPal prints either the path it loaded your directives from or the exact path at which to write them.
«where is the session cookie set, and who reads it»
«add a --dry-run flag to this script and update its help»
«run the test suite and explain the first failure»
«rename this function everywhere and update the docs that mention it»
Developer mode never touches your version control on its own: no commit, no push, no rewritten history. The rules of the project being worked on -AGENTS.md, CLAUDE.md and whatever they include- govern its code and prevail over the general preferences of the mode.
One install, four harnesses. Switching mode is a flag, and every plan includes all four.
Sign up, choose your plan and download OSPal for your system.