Jakub Synowiec

Use this agent to analyze the blast radius of a dependency upgrade by scanning lockfiles, manifests, and import graphs. Maps direct and transitive dependency relationships, identifies version constraints and peer conflicts, and scores upgrade impact. <example> Context: User asks what would be affected by a specific package upgrade. user: "What would break if we upgrade React from v17 to v18?" assistant: "I'll use the dependency-impact-map agent to trace the full dependency tree and import graph and produce an impact report." <commentary> Direct blast radius question — this agent traces the full dependency tree and import graph to produce a quantified impact report. </commentary> </example> <example> Context: User is blocked by dependency conflicts during an upgrade. user: "Are there peer dependency conflicts blocking this upgrade?" assistant: "I'll use the dependency-impact-map agent to parse lockfiles and map peer dependency constraints." <commentary> Conflict detection requires parsing lockfiles and mapping peer dependency constraints — this agent's core capability. </commentary> </example> <example> Context: The modernization-engineer agent is planning an upgrade and needs a blast radius report before generating the migration plan. <commentary> Proactive trigger: before any major upgrade, this agent should be dispatched to quantify risk and surface conflicts. </commentary> </example> <example> Context: User asks which files depend on a specific package without naming the analysis method. user: "How widely is lodash used in this codebase?" assistant: "I'll use the dependency-impact-map agent to trace lodash usages across source files." <commentary> Implicit trigger: the user wants import graph data. This agent traces usages across source files and reports counts and paths. </commentary> </example>

Use this agent for runtime upgrades, framework migrations, dependency updates, and technical debt reduction. Use PROACTIVELY when legacy patterns, outdated dependencies, deprecated APIs, or end-of-life runtimes are detected. This agent REPLACES the generic Plan agent for upgrade/migration tasks in plan mode. When plan mode Phase 2 calls for a Plan agent and the task involves upgrades, migrations, or dependency modernization, use this agent instead. Use this agent when user asks to modernize/upgrade/migrate/change a runtime/dependency/framework/etc. <example> Context: User explicitly requests a runtime upgrade. user: "Upgrade our app from Node 16 to Node 22" assistant: "I'll use the modernization-engineer agent to plan and execute the Node 16 to 22 upgrade." <commentary> Direct request for a runtime migration — this agent owns the full assessment, planning, execution, and verification workflow. </commentary> </example> <example> Context: User asks for a framework migration. user: "Migrate our Express app to Fastify" assistant: "I'll use the modernization-engineer agent to analyze the breaking changes and orchestrate the Express to Fastify migration." <commentary> Framework migration requires analyzing breaking changes, updating dependencies, and adapting code patterns — exactly what this agent orchestrates. </commentary> </example> <example> Context: Claude notices an end-of-life runtime or deprecated API while reading the codebase. <commentary> Proactive trigger: outdated dependencies, EOL runtimes, or deprecated API usage warrant offering this agent without being asked. </commentary> </example> <example> Context: User describes a problem caused by an outdated dependency without naming the solution. user: "Our build keeps failing with a warning about a deprecated webpack plugin" assistant: "I'll use the modernization-engineer agent to diagnose and resolve the deprecated webpack plugin issue." <commentary> Implicit trigger: the user describes a symptom of technical debt. This agent can diagnose and resolve it. </commentary> </example>

Identifies removed, renamed, and behavior-changing APIs between major versions of frameworks, libraries, or runtimes. Use after fetching release notes to classify API surface changes and their risk.

Runs a repository's build pipeline (lint, typecheck, tests, build) in a standardized order and classifies failures. Use when establishing a baseline before changes or detecting regressions after upgrades.

Fetches upstream release notes, changelogs, deprecation notices, and migration guides for a library or runtime version range. Use before analyzing API changes or planning upgrades.

Identifies which upgrade-affected components lack test coverage and scores risk by crossing change severity with coverage level. Use when planning an upgrade to flag risky untested paths before making changes.

Identifies build, test, lint, type-check, and formatting tooling in a repository. Use before running verification steps or assessing a project's development setup.

Synthesizes analysis findings (version checks, API deltas, impact mapping, test gaps) into an ordered, step-by-step migration plan with verification at each step. Use when analysis is complete and an executable upgrade plan is needed.

Determines latest stable or LTS versions of runtimes (Node.js, Python) and packages (npm, PyPI), checks EOL status, identifies upgrade paths, and looks up the VS Code compatibility matrix. Use when checking if project versions are outdated, need upgrading, or determining minimum VS Code engine version after a runtime change.