Diff Analyze

Documentation Index

Fetch the complete documentation index at: https://docs.nogic.dev/llms.txt

Use this file to discover all available pages before exploring further.

Diff Analyze turns a diff into a guided reading tool. Instead of summarizing the diff for you, it shows the actual code, reordered intelligently, classified by change type, with visible connections to the rest of the codebase and a blast-radius score for every file. The philosophy: show the code with superpowers, don’t replace it.

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Opening Diff Analyze

When AI agents (Claude Code, Codex, or any client connected to the Nogic MCP server) generate a diff analysis, it loads automatically (no manual step). You can also open the surface anytime from the toolbar’s Diff button, which shows the most recent change set and how many files it touches.

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What you see

Smart ordering. Files are sorted by the dependency graph, not alphabetically. New foundations appear first, then their callers, then unrelated changes, so the diff reads in the order that makes it make sense. Change classification. Every change is tagged: [NEW CODE], [MODIFICATION], [REFACTOR], [DELETION]. Filter to only the kinds that need careful reading. Connection arrows. Each modified function shows its callers and callees inline, with click-through navigation. You can trace impact without grepping. Blast radius. Every changed file gets a LOW / MEDIUM / HIGH impact score computed from the dependency graph. Auth middleware called by every API route lights up; an isolated utility doesn’t. Change groups. When a single session touches multiple unrelated areas, Nogic groups them. You read coherent slices rather than 15 random files. Convention checks. Test gaps and naming-convention violations surface as findings with risk levels (safe / warning / critical).

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Diff map

The Diff map view visualizes which files changed and which files are impacted (callers, callees, transitive blast radius). Use it to scope your read: zoom into the high-risk subgraph first, leave low-risk leaves for last.

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Sharing

Use Copy as Markdown to dump the full analysis into a PR description, Slack thread, or email. The export preserves grouping, classifications, blast radius, and findings.

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Language support

Diff Analyze builds on the same parsed graph as the visualizer, so smart ordering, blast radius, change groups, and connection arrows light up for JS / TS / Python. Files in other languages still show up in the diff with classification tags, but they don’t get graph-based scoring.

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How it stays fast

All analysis runs locally:

• Smart ordering, classification, connections, blast radius, grouping are pure graph + AST analysis on the same index that powers the visualizer
• AI is used only for naming change groups and explaining why a change matters

About 80% of the value lands without an AI roundtrip. Diff Analyze opens instantly even on large branches.

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Tuning cost & speed

Two settings control the AI authoring trade-offs. Defaults are tuned for Claude Pro/Max and Codex Plus/Pro — most users won’t need to touch them.

• nogic.diffAnalyze.modelTier (cheap | medium, default medium) — quality vs cost. medium uses Sonnet / codex-grade for reliable diagrams; cheap cuts cost ~3-5× by using Haiku / mini at the expense of multi-file diagram quality.
• nogic.diffAnalyze.concurrency (1-16, default 8) — how many groups author in parallel. Higher values finish faster but multiply peak in-flight API calls. Lower if you’re on Anthropic API tier 1.

See the Reference page for when to flip each. Both take effect on the next authoring run — no restart needed.

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Stale canvases

When your code changes after a canvas was authored, Diff Analyze doesn’t auto-regenerate it (that would burn tokens on every keystroke). Instead, the system tracks whether your edits fall outside the regions the canvas already described:

• Inside scope — your edit modifies code the canvas already covers. The canvas stays valid; no badge.
• Outside scope — you added new code in a region the canvas hadn’t seen. A small STALE badge appears on the affected group, and a banner appears in the Context card.

When you see one or more STALE badges, the toolbar surfaces a Refresh N stale button — click it to re-author all stale groups in parallel. Per-group refresh is also available from the badge itself. Edits that don’t change a group’s structure (member files + change types stay the same) reuse cached artifacts indefinitely. Reverting an edit hits the cache instantly.

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