Percy is a fork of Shelley — an awesome foundation built by Bold Software — with a bunch of new features on top.
Percy is a mobile-friendly, web-based, multi-conversation, multi-modal, multi-model, single-user coding agent. It does not come with authorization or sandboxing: bring your own.
Mobile-friendly because ideas can come any time.
Web-based, because terminal-based scroll back is punishment for shoplifting in some countries.
Multi-modal because screenshots, charts, and graphs are necessary, not to mention delightful.
Multi-model to benefit from all the innovation going on.
Single-user because it makes sense to bring the agent to the compute.
Percy remembers past conversations. After each conversation ends, messages are automatically chunked and indexed into a separate memory database. The agent can recall earlier decisions, code changes, and context using the memory_search tool. Supports hybrid search combining FTS5 keyword matching with optional vector embeddings (Ollama, or FTS5-only with zero dependencies).
Compiler-accurate code navigation powered by Language Server Protocol. The code_intelligence tool gives the agent five operations: definition, references, hover, symbols, and diagnostics. Works with Go (gopls), TypeScript, Python (pyright), Rust (rust-analyzer), and other LSP-enabled languages.
14 workflow skills ship embedded in the binary, covering test-driven development, systematic debugging, brainstorming, plan writing and execution, code review, git worktrees, parallel agent dispatch, and more. Skills follow the Agent Skills specification and can be overridden by user or project-level skills.
Percy discovers skills from multiple sources: bundled skills, user config directories (~/.config/percy/, ~/.percy/), shared agent skills (~/.config/agents/skills/), project .skills/ directories, and SKILL.md files anywhere in the project tree. Use the /skills command to see what's available.
Proactive monitoring of LLM context usage with warnings at 80% capacity, automatic retry on response truncation (up to 2 retries), and increased max output tokens (16,384) for longer responses.
When a conversation gets long, Percy can distill it into an operational brief and continue in a fresh conversation. The distillation preserves files modified, decisions made, current state, and next steps — everything the agent needs to pick up where it left off.
Get notified when the agent finishes work. Supports Discord webhooks and email, with a test endpoint to verify connectivity. Channels are configurable via the API and persist in the database.
curl -Lo percy "https://github.com/tgruben-circuit/percy/releases/latest/download/percy_$(uname -s | tr '[:upper:]' '[:lower:]')_$(uname -m | sed 's/x86_64/amd64/;s/aarch64/arm64/')" && chmod +x percyThe binaries are on the releases page.
brew install --cask tgruben-circuit/tap/percyYou'll need Go and Node.
git clone https://github.com/tgruben-circuit/percy.git
cd percy
makeThe technical stack is Go for the backend, SQLite for storage, and TypeScript and React for the UI.
The data model is that Conversations have Messages, which might be from the user, the model, the tools, or the harness. All of that is stored in the database, and we use a SSE endpoint to keep the UI updated.
Percy stands on the shoulders of Shelley by Bold Software. Shelley provided the solid core — the agentic loop, multi-model LLM integration, tool execution, SSE-based UI, and the mobile-friendly web interface. We're grateful for that foundation.
Shelley was itself partially based on Sketch.
Percy is Apache licensed. We require a CLA for contributions.
Run make. Run make serve to start Percy locally.
If you want to see how mobile looks, and you're on your home network where you've got mDNS working fine, you can run
socat TCP-LISTEN:9001,fork TCP:localhost:9000