Impact Radius

Impact Radius shows the blast radius of a change: for a given symbol, everything across the symbol graph that a change to it would affect — what breaks if you change this.

This is the hero of Code Cartography. The question you ask before every non-trivial edit — "what does this touch?" — usually gets answered by grep, hope, and a broken build later. Impact Radius answers it from the graph, up front.

See what a change would touch

Pick a symbol

Select the function, type, or class you're about to change — from the symbol browser or from anywhere it appears.

Read the radius

Altretta traces its cross-file relationships and shows the reach of a change: everything that references or depends on it across the whole codebase.

Change with confidence

Now you know the surface area before you edit — no surprise callers, no forgotten dependents, no build-and-pray.

Why this only works on a real graph

Impact Radius is possible because Altretta resolved your code into an actual symbol graph with cross-file references. A text tool can list the places a name appears; it can't tell you which of those are real dependents, and it can't follow a chain of relationships. Impact Radius follows the graph, so the blast radius is structural, not lexical.

This is why no notes app does this. Obsidian and Logseq can find the string; only a tool that understands source code as a graph can tell you what actually breaks.

When to reach for it

Before a refactor — scope the work honestly instead of discovering callers one failing test at a time.
Before a rename or signature change — see every site that has to move with it.
During review — understand the true reach of someone else's change, not just the diff.
When estimating — "small change, big radius" is exactly the trap this surfaces early.

Pair Impact Radius with Code Q&A: ask your AI why a dependent relies on the symbol, and get an answer cited to the real source.

Code Cartography

The overview of Altretta reading your repository as a structural graph.

The symbol graph

Where the relationships behind the radius come from.

Doc & decision drift

Catch the docs and decisions a change leaves behind.

Code Q&A

Ask your AI why a dependent relies on a symbol, cited to real source.

Glossary

Impact radius, symbol graph, and cross-file reference, defined.