I Built a CLI to Answer One Question: What Will This Change Break?

Description and use

Serval is a local CLI that analyzes dependency graphs, Git history, CI configuration, and critical-path rules to produce a deterministic risk score for a file change, enabling developers to assess blast radius quickly and integrate risk checks into CI pipelines.

Problem

Developers struggle to understand the blast radius of a code change, leading to accidental failures in large or unfamiliar codebases.

Outcome

Serval enables developers to quickly assess the potential impact of a file change with a deterministic risk score, reducing accidental failures and making risk visible before merge.

Workflow

• 1. Install Serval via Homebrew or download binary
• 2. Run serval inspect <file> to analyze a target file
• 3. Review the structured output showing direct/indirect impacts, CI workflows, git history, and risk score
• 4. Optionally use --explain for AI-generated natural language explanations
• 5. Integrate serval diff --fail-on high into CI to gate merges based on risk

Evidence

Serval is a local-first CLI that tries to answer one simple question: If I change this file, what am I likely to affect?

Source

The core score produced by Serval is deterministic. The same repository state and configuration produce the same result.

Source

Serval does support AI explanations. The AI cannot change the score.

Source