Veyyon sun

Veyyon

A terminal coding agent whose harness is built for inspectable context, controlled mutation, and long-running work.

Veyyon opens a four-phase todo plan, audits a nine-module service tree, writes one validating owner, fans out three subagents, applies a hash-anchored edit, runs the suite, advances the plan, signs the result through a stored secret placeholder, and opens context and settings operator surfaces in one continuous session

Veyyon uses the same model weights available in other clients. The difference is the workbench around them: a prompt you can inspect, model-native effort controls, explicit state ownership, protected secret spending, typed workers, language-server refactors, durable sessions, and tools that fail before stale state becomes a bad write.

Veyyon is a source fork of oh-my-pi. It is not a clean-room rewrite. UPSTREAM.md records the inherited foundation and the contracts Veyyon changed.

Install

Linux and macOS

curl -fsSL https://get.veyyon.dev | sh

Windows

irm https://veyyon.dev/install.ps1 | iex

The installer verifies the release checksum and binary before replacing an existing installation. See Install Veyyon for supported platforms, pinned releases, source checkouts, updates, rollback, and uninstall.

What Veyyon changes

Inspectable context. Prompt statements, layered project context, and context moves are visible before they affect a run. Prompt customization · Context files
Deliberate model control. Effort, roles, provider routing, and compaction remain explicit operator choices. Models and effort · Roles and profiles
Protected secret spending. Models use named placeholders while credentials remain local, encrypted, scoped, and auditable. Secret workflow
Visible workers. Typed subagents, IRC, persistent transcripts, and the Agent Control Center keep parallel work inspectable. Subagents
State-aware edits. Language-server refactors and hash-anchored patches fail before stale state becomes a bad write. Editing and repair

The Veyyon handbook explains the complete runtime and its contracts.

Explore

Provenance

Inherited foundation

Veyyon retains the Bun and TypeScript agent loop, terminal UI, provider catalog, role routing, hashline edit engine, mnemopi memory, and the original native grep, PTY, and tree-sitter hot-path foundations from oh-my-pi. These remain important product capabilities. They are not presented as Veyyon inventions.

Veyyon-owned contracts

Veyyon owns the statement-based prompt architecture, transactional context moves, model-native effort and explicit effort precedence, current compaction strategy and chains, provider-bound secret protection, profile/session durability rules, LSP write-through, capability and tool registry, typed worker and IRC operations, Agent Control Center, internal agent URLs, and post-fork reusable Rust crate boundaries and their current contracts.

This boundary describes this repository. It does not claim that current upstream has stood still. Read UPSTREAM.md, the mechanisms chapter, and the intentional divergence ledger for the detailed record.

Contributing

See CONTRIBUTING.md and packages/coding-agent/DEVELOPMENT.md for source setup, development commands, verification gates, and runtime conventions.

License

Veyyon is licensed under MIT. See LICENSE.

Run veyyon licenses to print the complete notice bundle embedded in every
release binary. The same bundle is available as
THIRD_PARTY_LICENSES.txt in a source checkout.

The project is derived from oh-my-pi. Upstream copyright and license notices are preserved in UPSTREAM.md and the source tree.