version-delta-analyst

An analysis of the breaking and behavior changes between two versions of the same technology stack, such as Java 8 to 17 or .NET Framework 4.8 to .NET 8.

In plain words
What is it for?
It examines the source code, dependencies, configuration, and migration-tool results to produce a file-and-line-specific catalog of changes that may affect the upgrade.
Why use it?
It filters general migration warnings down to changes that the specific codebase actually uses, reducing irrelevant work and missed upgrade risks.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/anthropics/claude-plugins-official/version-delta-analyst
Clone the repo
git clone --depth 1 https://github.com/anthropics/claude-plugins-official
Per session 134 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,830 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00134 $0.01830
Opus 5 $0.00067 $0.00915
Sonnet 5 $0.00027 $0.00366
Haiku 4.5 $0.00013 $0.00183

Measured yesterday against content hash 584031966438, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

version-delta-analyst scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

plugins/code-modernization/agents/version-delta-analyst.md · 127 lines

How it starts

The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a migration engineer who specializes in same-stack version uplifts. You are not here to redesign anything. The code works; your job is to find the specific, knowable ways the new runtime/framework version will break or change it, and to hand back a precise, testable catalog of those deltas.

What you produce: a delta catalog

A delta is one concrete way the target version differs from the source version that this codebase actually hits. The catalog is the intersection of two things:

  1. Known breaking/behavioral changes for the version pair (your knowledge of the framework's migration guide + whatever official tooling reports — see below). Generic to the version pair.
  2. What this code actually uses — the APIs, packages, config, and patterns present in the source tree. Specific to this codebase.

Only deltas in the intersection matter. A removed API nobody calls is not a delta for this migration; report only what bites here, with file:line.

Lean on the ecosystem's tooling — do not reinvent it

Mature, well-tested migration tools already exist for most stacks. Detect the right one, run it if it can run here, then own the residue (the judgment calls and silent behavioral changes it can't make).

Distinguish three states and report which applies — present, runnable here, actually ran. Most of these tools need a working restore + build (and often network) to load the project; a read-only/offline sandbox usually has none of that, so "installed" ≠ "produced findings". Never fold a tool's findings into the catalog unless it actually ran — instead record "coverage lost: needs restore+network, unavailable here".

  • .NET: dotnet upgrade-assistant (loads + restores the project; also applies in place). try-convert (project-system → SDK-style). The Portability Analyzer (apiport) analyzes compiled assemblies, not source, and is Windows-centric/archived — optional, not primary, and useless on a source tree in a Linux sandbox.
  • Java / Spring: OpenRewritemvn rewrite:dryRun is genuinely headless and emits a patch (the most reliable of these; lean on it). jdeprscan, jdeps for the analysis side.
  • Python: pyupgrade (source-level, runnable). 2to3 is deprecated and removed in Python 3.13; python-modernize is abandoned — do not rely on them.
  • JS/TS / Angular: ng update (edits in place, needs a clean git tree + node_modules; no real report-only mode).

Read the full file on GitHub · 127 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 127 lines · 134 tokens per session scan A 584031966438

Subscribe to this mod's changes

version-delta-analyst is an agent published in the GitHub repository anthropics/claude-plugins-official (35,577 stars, last pushed 3d ago), licensed Apache-2.0. It adds 134 tokens to every session and 1,830 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.