Arbor is a pull request review companion. It walks changed code paths and tells solo devs, small teams, and AI agents what might break before merge.

Can AI coding agents use Arbor?

Yes. Arbor produces a compact PR brief with risky paths, likely side effects, unknown edges, and the first test to write so agents can keep edits scoped.

Does Arbor work with GitHub pull requests?

Yes. Arbor installs as a GitHub App, analyzes pull requests, and comments with the breakage path reviewers should inspect.

Back to Arbor

Changelog

We ship the graph, then we polish the operator loop around it.

This is the public record of what changed in Arbor Cloud: engine work, product shifts, dashboard fixes, launch polish, and the hardening that makes the PR walk usable by real teams.

PR breakage mapdashboard UXagent handoffruntime hardening

0.9.0Polish

April 2026

Operator polish and mobile-first launch pass

Arbor now feels like one connected product instead of a stack of promising parts. This release focused on mobile hero quality, dashboard cohesion, auth smoothing, and public pages that finally match the shipped experience.

Rebuilt the landing hero around PR breakage maps instead of a decorative desktop graph.
Improved mobile layouts so the landing page reads clearly on phone-sized screens without losing the product story.
Normalized dashboard lifecycle states so completed analyses stop rendering as in progress across views.
Smoothed first-time GitHub sign-in recovery when a valid session exists after OAuth redirect.

0.8.5Fix

April 2026

Runtime hardening and status quality

Launch reliability work across the API and GitHub integration paths so teams can trust the operator loop around the analysis engine.

Added readiness checks, request IDs, request timeouts, and structured tracing around webhook and worker flows.
Improved commit-status target URLs so failing checks land on the right Arbor run page.
Made status-post failures non-fatal to analysis completion where appropriate.
Improved rate-limit feedback and retry metadata for better operational debugging.

0.8.0Major

April 2026

Breakage analysis pipeline

Breakage analysis is now a first-class stage in Arbor. The engine classifies changed code, walks reachable paths, and emits structured PR notes instead of vague reviewer prose.

Added classifier heuristics across 10 surface categories.
Added upstream and downstream call-path tracing through the graph.
Added framework-aware entrypoint detection for common web stacks.
Added repo rule loading from .arbor/security.yml and .arbor/security.json.

0.7.0Major

March 2026

PR breakage product pivot

Arbor moved from generic blast-radius language to concrete PR breakage paths. The product is now positioned around context for AI-generated pull requests.

Reframed the dashboard around reachable paths, likely side effects, and next checks.
Introduced frontend run contracts to safely consume backend-native path output.
Added controls for monitor, review, block, owner handles, tests, and unknown path handling.
Removed overclaiming language around certainty and universal vulnerability detection.

0.6.0Engine

February 2026

Private engine expansion

The private engine gained multidimensional scoring, weighted signal fusion, and stronger calibration plumbing for richer PR decisions.

Added four-dimensional scoring across correctness, risk, reliability, and maintainability.
Added 21 signals with reliability weighting and freshness decay.
Added conditional verdicts and stronger scenario regression coverage.
Expanded calibration and property-based testing in the private engine path.

0.5.0Major

December 2025

GitHub App and cloud dashboard

Arbor Cloud launched with GitHub installation flow, PR analysis history, billing, and the first production dashboard.

Shipped GitHub OAuth and repository-aware dashboard flows.
Added webhook verification and durable queued analysis processing.
Added billing and subscription wiring for the hosted product.
Deployed API on Render and frontend on Vercel.

0.4.0Archive

November 2025

Blast-radius foundations

The original Arbor graph engine shipped with tree-sitter parsing, petgraph topology, and the first generation of upstream and downstream impact analysis.

Built tree-sitter parsing across 14 languages.
Built graph construction with caller and callee traversal.
Shipped the first PR comment with structural dependency impact.

Back to Arbor

Changelog

We ship the graph, then we polish the operator loop around it.

This is the public record of what changed in Arbor Cloud: engine work, product shifts, dashboard fixes, launch polish, and the hardening that makes the PR walk usable by real teams.

PR breakage mapdashboard UXagent handoffruntime hardening

0.9.0Polish

April 2026

Operator polish and mobile-first launch pass

Rebuilt the landing hero around PR breakage maps instead of a decorative desktop graph.
Improved mobile layouts so the landing page reads clearly on phone-sized screens without losing the product story.
Normalized dashboard lifecycle states so completed analyses stop rendering as in progress across views.
Smoothed first-time GitHub sign-in recovery when a valid session exists after OAuth redirect.

0.8.5Fix

April 2026

Runtime hardening and status quality

Launch reliability work across the API and GitHub integration paths so teams can trust the operator loop around the analysis engine.

Added readiness checks, request IDs, request timeouts, and structured tracing around webhook and worker flows.
Improved commit-status target URLs so failing checks land on the right Arbor run page.
Made status-post failures non-fatal to analysis completion where appropriate.
Improved rate-limit feedback and retry metadata for better operational debugging.

0.8.0Major

April 2026

Breakage analysis pipeline

Breakage analysis is now a first-class stage in Arbor. The engine classifies changed code, walks reachable paths, and emits structured PR notes instead of vague reviewer prose.

Added classifier heuristics across 10 surface categories.
Added upstream and downstream call-path tracing through the graph.
Added framework-aware entrypoint detection for common web stacks.
Added repo rule loading from .arbor/security.yml and .arbor/security.json.

0.7.0Major

March 2026

PR breakage product pivot

Arbor moved from generic blast-radius language to concrete PR breakage paths. The product is now positioned around context for AI-generated pull requests.

Reframed the dashboard around reachable paths, likely side effects, and next checks.
Introduced frontend run contracts to safely consume backend-native path output.
Added controls for monitor, review, block, owner handles, tests, and unknown path handling.
Removed overclaiming language around certainty and universal vulnerability detection.

0.6.0Engine

February 2026

Private engine expansion

The private engine gained multidimensional scoring, weighted signal fusion, and stronger calibration plumbing for richer PR decisions.

Added four-dimensional scoring across correctness, risk, reliability, and maintainability.
Added 21 signals with reliability weighting and freshness decay.
Added conditional verdicts and stronger scenario regression coverage.
Expanded calibration and property-based testing in the private engine path.

0.5.0Major

December 2025

GitHub App and cloud dashboard

Arbor Cloud launched with GitHub installation flow, PR analysis history, billing, and the first production dashboard.

Shipped GitHub OAuth and repository-aware dashboard flows.
Added webhook verification and durable queued analysis processing.
Added billing and subscription wiring for the hosted product.
Deployed API on Render and frontend on Vercel.

0.4.0Archive

November 2025

Blast-radius foundations

The original Arbor graph engine shipped with tree-sitter parsing, petgraph topology, and the first generation of upstream and downstream impact analysis.

Built tree-sitter parsing across 14 languages.
Built graph construction with caller and callee traversal.
Shipped the first PR comment with structural dependency impact.