piscesA coding agent built for embedding

RPC-first · session trees · zero-cost rules · Rust-native core

RPC mode & SDK

Run as a headless subprocess over newline-delimited JSON-RPC on stdio, or embed directly via the TypeScript SDK. Both surfaces expose identical session control, event streaming, and tool wiring — no TUI required.

RPC reference

Session tree with branching

Every message is a node in an append-only tree. Branch at any point, navigate back through history, hand off to a new session with generated context — without rewriting or losing prior work. Compaction summarises only what you choose.

Session model

Time-Traveling Stream Rules (TTSR)

Rules inject themselves mid-stream the moment the model's output matches a trigger pattern, then the interrupted generation retries with the rule already in context. Zero upfront token cost — rules consume no context until they fire.

TTSR lifecycle

Parallel subagents with isolation

Dispatch typed task batches to named agents running in parallel. Pass isolated=true to run each agent in a git worktree; results come back as diff patches. Spawn depth is enforced — agents cannot recurse beyond the configured limit.

Task agents

Rust-native core

Grep, glob, fuzzy-find, PTY, syntax highlighting, ANSI-aware text operations, and clipboard all run through a Rust N-API module with a shared FS scan cache. No spawning external processes for search primitives.

Natives architecture

Persistent IPython kernel

Python cells run in a Jupyter kernel gateway — the kernel persists across calls so variables, imports, and state survive between turns. Rich output (dataframes, plots, Mermaid diagrams) renders inline.

Python runtime

Structured blob & artifact storage

Large outputs, images, and subagent results live outside the session JSONL in content-addressed blobs (global, deduplicated by SHA-256) or session-scoped artifact files. Context stays lean; full output is always retrievable via artifact:// URIs.

Storage architecture

Deep extension & plugin model

Register LLM-callable tools, slash commands, keyboard shortcuts, event interceptors, and custom renderers from a single TypeScript factory. Install plugins from any Git-hosted catalog compatible with the Claude plugin registry format.

Extensions guide