fj-ai 0.1.0

fj — one-shot CLI coding agent powered by soothe-nano

fj

fj is a one-shot coding-agent CLI. Everything after the command is the query:

fj who is your name
fj 修改这个文件。
fj explain the auth flow in this repo

It embeds soothe-nano — a full coding CoreAgent (tools, skills, MCP, subagents, progressive loading) — with default SQLite persistence and config at ~/.soothe/config/nano.yml.

fj-ai is the Python package name; the agent runtime is soothe-nano. This README documents both the CLI and the agent capabilities you get underneath.

Quick start

1. Install

pip install fj-ai
# or
uv tool install fj-ai

Requires Python 3.11+.

2. Minimal config (no external SaaS)

Copy the example and point it at a local OpenAI-compatible server (Ollama, LM Studio, vLLM, …). No Tavily, Langfuse, Postgres, or browser stack required.

mkdir -p ~/.soothe/config
cp nano.yml ~/.soothe/config/nano.yml
# or run without installing into ~/.soothe:
#   fj -c ./nano.yml who are you

The repo-root nano.yml is a validated minimal profile: local OpenAI-compatible provider (Ollama), SQLite, search/research/browser subagents off.

Start Ollama (or your local server), pull a model, then:

fj who are you
fj list Python files in this directory

Zero-config alternative (cloud API, still no extra services):

export OPENAI_API_KEY=sk-...
# optional: export OPENAI_BASE_URL=https://api.openai.com/v1
fj summarize README.md

If ~/.soothe/config/nano.yml is missing, soothe-nano bootstraps from OPENAI_API_KEY or ANTHROPIC_API_KEY.

3. What fj sets up for you

Concern	Default
Config	~/.soothe/config/nano.yml (SOOTHE_HOME overrides home)
Checkpoints	SQLite at ~/.soothe/data/soothe_checkpoints.db
Workspace	Current working directory (SOOTHE_WORKSPACE)
Output	Ephemeral progress on stdout line 1; final answer only when done

Usage

fj [options] [--] <query...>

Flag	Meaning
-c PATH / --config	Alternate nano.yml
-t ID / --thread	Reuse a LangGraph thread id (multi-turn via sqlite)
-w DIR / --workspace	Workspace root for file/shell tools
--no-stream	Same final-only answer (progress still shown on a TTY)
-v / --verbose	Also mirror tool/custom events on stderr
-V / --version	Version
--	Force remaining argv into the query (including leading -)

Examples:

fj who is your name
fj 修改这个文件。
fj -v refactor the CLI parser to support Unicode
fj --thread demo-1 continue from last turn: what files did you touch?
fj -w ~/code/myapp find TODO comments

Add skills

Skills are folders with a SKILL.md (frontmatter + instructions). Point nano at them in nano.yml:

skills:
  - ~/.soothe/skills/my-reviewer
  - ./skills/deploy

Example skill layout:

~/.soothe/skills/my-reviewer/
  SKILL.md

---
name: my-reviewer
description: Review Python PRs for style and security
---

# Reviewer

When asked to review code, check for ...

Progressive skills (on by default): the agent keeps a compact catalog in context and loads full skill bodies on demand via search_skills / invoke_skill, with optional intent prefetch on cold threads. Tune under progressive_skills: in nano.yml (budget %, core skills, semantic search).

Add MCP servers

MCP is opt-in. Either enable builtins or declare servers:

# Builtin names (playwright, github, slack, postgres, gdrive, …)
mcp_builtins:
  - playwright

# Or explicit servers (stdio / SSE / HTTP / websocket)
mcp_servers:
  - name: filesystem
    transport: stdio
    command: npx
    args: ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"]
    defer: true          # progressive: tools listed, activated when needed
    enabled: true

Progressive MCP: with defer: true (default), MCP tools are not dumped into the full tool array; the agent discovers and activates them as needed within a listing budget (progressive_mcp:).

Agent features (soothe-nano / fj-ai)

fj is a thin CLI; the agent is soothe-nano, built on soothe-deepagents + soothe-sdk.

Progressive loading

Layer	Behavior
Tools	Core tools bound at startup; deferred tools discovered via search_tools (progressive_tools)
Skills	Compact listings + search_skills / invoke_skill; intent prefetch on turn 0
MCP	Servers deferred by default; tools activated on demand

This keeps the context window small on every turn while still exposing a large capability surface.

Coding product defaults (beyond raw deepagents)

• Builtin tool groups: shell/execution, file ops, HTTP, data, datetime, optional search
• Ready subagents: planner, explorer, deep/academic research, browser-use (disable what you do not need)
• Workspace scoping + path security policies
• YAML / env config factory (SootheConfig)
• SQLite-first persistence (Postgres optional in nano for larger deployments)
• Middleware: context limits, tool timeouts, rate-limit retries, edit coalescing, role routing

Optimizations inspired by / layered on deepagents

deepagents provides the harness (filesystem, shell, todos, subagents, context management). soothe-nano adds production-shaped defaults and progressive discovery so a coding agent can run in a repo without hand-wiring every tool and prompt. fj then packages that as a single argv → agent CLI with sqlite threads and cwd as workspace.

Compared to other agents

	fj / soothe-nano	deepagents	OpenCode	Pi / pi-agent style
Shape	Library + thin CLI	Python harness library	Full TUI product (JS/TS)	Minimal / research-oriented agent loops
Install surface	pip install fj-ai	pip install deepagents	Native/npm installer	Varies by project
Config	~/.soothe/config/nano.yml	Code-first	App/project config	Usually code or light config
Tools in context	Progressive (core + search)	Bring-your-own / harness set	Product tool surface	Often smaller fixed sets
Skills	Progressive SKILL.md catalog	Base / custom	Product skills/plugins	Optional / custom
MCP	First-class, deferred by default	Via adapters if you wire them	Product MCP support	Depends on fork
Persistence	SQLite default under ~/.soothe/data	Pluggable checkpointer	Product session store	Often ephemeral
Subagents	Planner / research / browser ready	You define task agents	Product multi-agent UX	Usually single loop
Best when	Scriptable coding agent in a repo	Custom harness control	Interactive daily coding IDE-in-terminal	Experiments, minimal loops

vs deepagents: use deepagents when you want the harness and full control; use fj/nano when you want coding defaults, progressive skills/tools/MCP, and a one-line CLI.

vs OpenCode: OpenCode is a rich interactive TUI product. fj is intentionally small — argv in, streamed answer out — while sharing the same class of capabilities (tools, MCP, skills) through soothe-nano.

vs Pi-agent-style agents: Pi-oriented agents emphasize lean loops and simplicity. fj trades a bit of that minimalism for progressive loading, workspace security, and sqlite threads so longer coding sessions stay practical.

Development

git clone https://github.com/caesar0301/fj-ai.git
cd fj-ai
make sync-dev
make test
make lint

# Run against a local soothe-nano checkout (optional):
#   uv add --editable ../soothe/packages/soothe-nano
uv run fj who is your name

Project layout

src/fj_ai/
  cli.py       # argv → query, asyncio entry
  config.py    # ~/.soothe/config/nano.yml loader
  agent.py     # create_nano_agent + sqlite checkpointer
  stream.py    # stdout streaming
nano.yml                 # minimal local config
.github/workflows/
  ci.yml
  release.yml

CI / release

• CI — format, lint, unit tests on Python 3.11–3.13; build + twine check
• Release — on GitHub Release publish (or workflow_dispatch), build and publish to PyPI (UV_PUBLISH_TOKEN or OIDC trusted publishing)

License

MIT