arbor

Question

Arbor answer

If I change this symbol, what breaks?

Blast radius with depth, confidence, and risk level

Who calls this — directly and transitively?

Caller/callee traversal on the call graph

What's the shortest path between A and B?

A* path through real dependencies

Is this PR too risky to merge?

CI gate on blast-radius thresholds

Fix

Why it mattered

Colliding symbols are kept

SymbolTable used HashMap::insert, so a second handler, new, or process replaced the first. The loser had zero callers and was invisible to blast radius.

Resolution is deterministic

Same-directory locality was decided by iterating a HashMap. Rust seeds RandomState per process, so the same binary on the same input could build different edges between runs. Now asserted across eight fresh processes.

Edges carry confidence

A proven same-file call and a same-directory guess were identical evidence. Each edge now scores [0,1] by how it resolved.

Exported TS symbols indexed once

export_statement recursed into its children, then the generic loop recursed again — every exported symbol became two vertices sharing one node id. 133 phantom nodes on a 149-file app, 25% of the graph.

Method calls on untyped receivers resolve

obj.method() was dropped outright, leaving the graph nearly edgeless on TS/JS — and an empty graph reports a blast radius of zero, which reads as "safe" rather than "unknown".

Centrality is a percentile rank

Scores were divided by the graph maximum, so the top node was 1.0 by construction and a 0.6 threshold meant nothing consistent between repos. Adding one hub rescaled every other node.

Resolution is O(1), not O(refs × nodes × files)

Unresolvable references — stdlib and third-party calls, most call sites in real code — paid the worst case. Suffixes are now indexed.

Codebase

Before

After

TypeScript (149 files)

172 edges

196 (+14%)

Rust (arbor-graph)

116 edges

167 (+44%)

Change

Measured

PageRank rewrite — flat call-graph adjacency replaces per-iteration traversal

149.8ms → 6.6ms on a 10k-node graph (23x), verified side-by-side vs the old implementation

Parallel indexing — parse fans out across all cores, deterministic assembly

Arbor: 253ms → 95ms · tokio (178k LOC): 2.7s → 1.6s

Warm-start centrality — watcher recomputes seed from previous scores

Converges in ~2 rounds after a one-file patch instead of the full 20-iteration budget

Convergence early-exit

Iteration stops at 1e-9 max delta — the budget is a ceiling, not a sentence

Feature

What it does

MCP 2026-07-28

Stateless server/discover, response caching (ttlMs/cacheScope), dual-version fallback for 2025-03-26 clients

Tasks extension

tasks/get · tasks/update · tasks/cancel — cold-start indexing returns task handles, not errors

MCP Apps

Interactive blast-radius graph (ui://arbor/blast-radius) and architecture map (ui://arbor/architecture-map) inside agent hosts

HTTP transport

arbor bridge --http --port 3333 — stateless MCP behind load balancers

Real get_blast_radius

Git-diff-aware impact analysis via shared arbor-graph::compute_blast_radius

Pagination

offset / limit / hasMore on search_symbols and get_map

Benchmarks

Criterion suite + CI regression gate — see BENCHMARKS.md

Tier

Tools

Use when

Orientation

get_map

First call — token-budgeted project skeleton ranked by PageRank

Surgical

list_entry_points · get_callers · get_callees · search_symbols · get_file_graph · get_node_detail

Navigate to a specific symbol or file

Broad

get_logic_path · analyze_impact · find_path · get_knowledge_path

Trace dependencies, blast radius, paths

Agent-native

get_blast_radius · explain_symbol · audit_security · get_architecture_overview · batch_query

PR impact, onboarding, security audit, bulk lookup

Command

Description

arbor setup

One-shot init + index

arbor map

Ranked, token-budgeted project skeleton

arbor query <term>

Fuzzy symbol search (supports | OR)

arbor callers / callees <sym>

One-hop graph traversal

arbor entry-points

HTTP handlers, main, jobs, webhooks

arbor file-graph <path>

Symbols + edges in one file

arbor inspect <sym>

Full symbol detail

arbor path <a> <b>

Shortest call-graph path

arbor refactor <sym>

Blast radius before refactoring

arbor diff

Git-change impact report

arbor check

CI safety gate (--max-blast-radius N)

arbor summary

Auto-generate PR description

arbor agent review

Autonomous PR architecture review

arbor agent onboard

Codebase onboarding guide

arbor agent guard

Real-time architectural safety gate

arbor bridge

MCP server (add --http for HTTP transport)

arbor watch

Live re-index on file changes

arbor gui

Native desktop UI