focus

An LLM agent framework in Rust, structured as a Cargo workspace. Built to learn the architecture of pi by reimplementing its core layers with a minimal dependency surface (tokio + rustls only).

This milestone focuses on calling Z.ai / 智谱 GLM coding models (glm-5.2, domestic endpoint) end-to-end.

Quick start

1. Create a config file

Copy the example (it lists providers but no API keys — those go in auth.json via /login):

mkdir -p ~/.focus
cp examples/config.example.json ~/.focus/config.json

The config (~/.focus/config.json) selects a default provider and lists available ones (host, model). Override the config dir with FOCUS_CONFIG_DIR.

2. Log in (save your API key)

Run focus with no arguments to enter the interactive REPL, then use the /login slash command:

./target/debug/focus
> /login zai-coding-cn
Enter API key for zai-coding-cn: <paste your 智谱 API key>
Credentials saved to ~/.focus/auth.json
> /quit

Your key is stored in ~/.focus/auth.json (mode 0600). Log out with /logout [provider].

3. Run

cargo build --workspace
# Interactive REPL (multi-turn conversation):
./target/debug/focus
> 你好
你好！有什么可以帮你的？
> /quit
# Single prompt (one-shot):
./target/debug/focus "用一句话解释什么是 Rust"
# Or pipe via stdin:
echo "写一个快排" | ./target/debug/focus
# Override the model:
./target/debug/focus --model glm-5.2 "hello"
# One-off API key (in-memory only, not saved):
./target/debug/focus --api-key YOUR_KEY "hello"
# Print the resolved config:
./target/debug/focus --config

focus --help shows all options.

REPL slash commands

Inside the REPL (focus with no prompt, on a TTY):

Command	Action
/login [provider]	store an API key in ~/.focus/auth.json
/logout [provider]	remove a stored credential
/provider [name]	show or switch the active provider
/model [name]	show or switch the active model
/system [text]	show or set the system prompt
/clear / /new	clear the conversation transcript
/config	print the resolved provider config
/help	list commands
/quit	exit focus

Plain text is sent to the model as a prompt; the conversation is multi-turn (the transcript persists across prompts).

Credential resolution order

When running a prompt, the API key is resolved in this order (highest first):

1. --api-key CLI flag (in-memory only, never persisted)
2. ~/.focus/auth.json entry (written by focus login)
3. config.json provider apiKey field (if present)

3. Run the real-call smoke test (optional)

ZAI_API_KEY=<key> cargo test -p focus-providers --test zai_smoke -- --ignored --nocapture

Architecture

See docs/architecture/ for the pi reference analysis. The workspace mirrors pi's layering:

focus-json       minimal JSON parser/serializer (zero deps)
focus-core       domain types, agent loop, Tool/StreamProvider traits
focus-transport  HTTP/1.1, TLS (rustls), SSE parser
focus-providers  Z.ai / OpenAI-compat + Anthropic providers
focus-cli        config loading + single-prompt runner
focus-tools      (placeholder) file/shell tools
focus-harness    (placeholder) session persistence + compaction

Dependency flow is strictly one-way: core never depends on transport, providers, or tools. All I/O crosses trait boundaries.

Verification

cargo fmt --all --check
cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspace

All 95 unit/integration tests pass with zero clippy warnings. See AGENTS.md for the full engineering spec.