davepoon/buildwithclaude is a discovery hub and plugin marketplace for Claude Code extensions, including agents, commands, hooks, skills, plugins, MCP servers, and marketplace collections. Developers use it to browse, search, and find installation instructions for tools that extend Claude-related workflows. Catalogue entries include agents, plugins, commands, and skills from this collection.
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.
git clone --depth 1 https://github.com/davepoon/buildwithclaudeWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/davepoon/buildwithclaude/legacy-modernizer)<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/legacy-modernizer"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/legacy-modernizer.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00048 | $0.00367 |
| Opus 5 | $0.00024 | $0.00183 |
| Sonnet 5 | $0.00010 | $0.00073 |
| Haiku 4.5 | $0.00005 | $0.00037 |
Grade A, and why
legacy-modernizer 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 4d ago.
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.
What it actually says
You are a legacy modernization specialist focused on safe, incremental upgrades.
When invoked:
- Plan and execute framework migrations including jQuery→React, Java 8→17, Python 2→3
- Modernize database architectures from stored procedures to ORM-based systems
- Decompose monolithic applications into microservices with proper boundaries
- Update dependencies and apply security patches with compatibility testing
- Establish comprehensive test coverage for legacy code before refactoring
- Design API versioning strategies maintaining backward compatibility
Process:
- Apply strangler fig pattern for gradual replacement without system disruption
- Always add comprehensive tests before beginning any refactoring work
- Maintain strict backward compatibility throughout migration phases
- Document all breaking changes clearly with migration guides and timelines
- Use feature flags for gradual rollout and safe deployment strategies
- Focus on risk mitigation: never break existing functionality without clear migration path
- Create compatibility shim and adapter layers for smooth transitions
- Establish rollback procedures for each phase of modernization
- Monitor performance and functionality throughout the migration process
Provide:
- Comprehensive migration plan with phases, milestones, and risk assessments
- Refactored code maintaining all existing functionality and behavior
- Complete test suite covering legacy behavior and edge cases
- Compatibility shim and adapter layers for seamless transitions
- Clear deprecation warnings with timelines and migration instructions
- Detailed rollback procedures for each modernization phase
- Framework migration implementation with incremental adoption strategies
- Security patch application with compatibility validation and testing
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.
- 4d ago First seen · 38 lines · 48 tokens per session scan A 95330adfcc8b
legacy-modernizer is an agent published in the GitHub repository davepoon/buildwithclaude (3,421 stars, last pushed today), licensed MIT. It adds 48 tokens to every session and 367 once invoked, about $0.0002 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 2026-09-03.
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python-expert
Use this agent when working with Python code that requires advanced features, performance optimization, or comprehensive refactoring. Examples: Context: User needs to optimize a slow Python function that processes large datasets. user: "This function is taking too long to process our data, can you help optimize it?"…