crate-development

name	crate-development
description	Use when adding features, fixing bugs, or refactoring code in any Auto-Tundra crate. Covers build, test, lint, and validation workflows.
allowed_tools	["Bash","Read","Edit","Write"]
references	["/Users/studio/rust-harness/AGENTS.md","/Users/studio/rust-harness/CONTRIBUTING.md","/Users/studio/rust-harness/Cargo.toml"]

Crate Development

Trigger

Use this skill when modifying Rust source code in any crates/at-* directory, app/tauri, or app/leptos-ui.

Workspace Layout

crates/
  at-core/          # Types, config, context engine (foundation — minimal deps)
  at-agents/        # Agent roles, executor, registry, prompts
  at-intelligence/  # LLM providers, router, cost tracking, api_profiles
  at-harness/       # Rate limiting, circuit breaker, MCP, security
  at-daemon/        # Orchestrator, event bus, task pipeline
  at-bridge/        # HTTP/WS API (axum), the main handler file is http_api.rs
  at-session/       # PTY terminal pool
  at-integrations/  # GitHub, GitLab, Linear clients
  at-telemetry/     # Metrics, tracing, Datadog
  at-cli/           # CLI binary (clap)
  at-tui/           # TUI binary (ratatui)
app/
  tauri/            # Desktop shell
  leptos-ui/        # WASM frontend

Non-Negotiable Workflow

1. Before editing: understand the dependency direction

at-core ← at-session, at-integrations, at-telemetry
       ← at-harness ← at-intelligence ← at-agents
                                        ← at-daemon ← at-bridge
                                                     ← at-cli, at-tui

Never add a dependency from a lower-layer crate to a higher one.

2. After every edit: validate

# Check the touched crate compiles
cargo check -p at-<crate>

# Run tests for the touched crate
cargo nextest run -p at-<crate>

# If touching at-core or at-harness, also check downstream:
cargo check -p at-agents -p at-intelligence -p at-bridge

3. Before claiming completion

# Lint
cargo clippy -p at-<crate> -- -D warnings

# Format
cargo fmt -- --check

# If touching API endpoints, verify with curl:
curl -s http://localhost:9090/api/<endpoint> | jq .

Adding a New Feature

New agent role

1. Add variant to at-core/src/types.rs → AgentRole
2. Implement RoleConfig in at-agents/src/roles/<name>.rs
3. Register in at-agents/src/registry.rs
4. Add tests

New API endpoint

1. Add handler function in at-bridge/src/http_api.rs
2. Add route in api_router_with_auth()
3. Add request/response types
4. Add test in crates/at-bridge/tests/http_api_test.rs

New CLI command

1. Add variant to Commands enum in at-cli/src/main.rs
2. Create handler in at-cli/src/commands/<name>.rs
3. Export from at-cli/src/commands/mod.rs
4. Wire in main() match arm
5. Add test

Common Pitfalls

• http_api.rs is 4000+ lines — search carefully before adding duplicate routes.
• at-core is depended on by everything — breaking changes cascade.
• Always use #[cfg(test)] for test modules, not standalone test files in src/.
• Integration tests that hit the network should be gated behind #[ignore] or env vars.
• The Leptos frontend is WASM — #[cfg(target_arch = "wasm32")] guards apply.