| name | managing-cargo |
| description | Use when working with Cargo — cargo Rust build and package management. Covers
build configuration, workspace management, feature flags, build profiles,
cross-compilation, and build script analysis. Use when managing Cargo
workspaces, configuring build profiles, debugging compilation issues, or
optimizing build performance.
|
| connection_type | cargo |
| preload | false |
Cargo Build and Package Management Skill
Manage and analyze Cargo builds, workspaces, features, and build configurations.
MANDATORY: Discovery-First Pattern
Always check current Cargo.toml and workspace configuration before modifying builds.
Phase 1: Discovery
#!/bin/bash
echo "=== Cargo.toml ==="
cat Cargo.toml 2>/dev/null | head -25
echo ""
echo "=== Workspace Structure ==="
grep -A15 '\[workspace\]' Cargo.toml 2>/dev/null | head -15
echo ""
echo "=== Build Profiles ==="
grep -A5 '\[profile' Cargo.toml 2>/dev/null | head -15
echo ""
echo "=== Cargo Version ==="
cargo --version 2>/dev/null
rustc --version 2>/dev/null
Phase 2: Analysis
#!/bin/bash
echo "=== Feature Flags ==="
grep -A20 '\[features\]' Cargo.toml 2>/dev/null | head -15
echo ""
echo "=== Build Dependencies ==="
grep -A20 '\[build-dependencies\]' Cargo.toml 2>/dev/null | head -10
echo ""
echo "=== Target Configuration ==="
grep -A5 '\[\[bin\]\]\|\[lib\]' Cargo.toml 2>/dev/null | head -15
echo ""
echo "=== Build Timing ==="
cargo build --timings 2>/dev/null | tail -5
Output Rules
- TOKEN EFFICIENCY: Target <=50 lines per output
- Summarize workspace members and their types
- List feature flags with dependencies
- Report build profile optimizations
Common Operations
Build Analysis
#!/bin/bash
echo "=== Build Check ==="
cargo check 2>&1 | tail -10
echo ""
echo "=== Clippy Lints ==="
cargo clippy 2>&1 | tail -15
Cross-Compilation
#!/bin/bash
echo "=== Installed Targets ==="
rustup target list --installed 2>/dev/null
echo ""
echo "=== Available Targets ==="
rustup target list 2>/dev/null | grep -E 'linux|darwin|windows' | head -10
Safety Rules
- Run
cargo check before full builds to catch errors quickly
- Test with
--release profile before deploying -- debug and release can behave differently
- Review feature flag combinations for compile-time correctness
- Use
cargo clippy to catch common Rust anti-patterns before merging
Output Format
Present results as a structured report:
Managing Cargo Report
═════════════════════
Resources discovered: [count]
Resource Status Key Metric Issues
──────────────────────────────────────────────
[name] [ok/warn] [value] [findings]
Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]
Target ≤50 lines of output. Use tables for multi-resource comparisons.
Anti-Hallucination Rules
- NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
- NEVER fabricate metric names or dimensions — verify against the service documentation or
--help output.
- NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
- ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
- ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.
Counter-Rationalizations
| Shortcut | Counter | Why |
|---|
| "I'll skip discovery and check known resources" | Always run Phase 1 discovery first | Resource names change, new resources appear — assumed names cause errors |
| "The user only asked for a quick check" | Follow the full discovery → analysis flow | Quick checks miss critical issues; structured analysis catches silent failures |
| "Default configuration is probably fine" | Audit configuration explicitly | Defaults often leave logging, security, and optimization features disabled |
| "Metrics aren't needed for this" | Always check relevant metrics when available | API/CLI responses show current state; metrics reveal trends and intermittent issues |
| "I don't have access to that" | Try the command and report the actual error | Assumed permission failures prevent useful investigation; actual errors are informative |
