protogen

A Maven tool that generates safer builders for Protocol Buffers, a format used to define structured messages between programs. The generated code can catch some missing required fields while compiling.

In plain words
What is it for?
Use it when configuring the Maven plugin, generating protobuf builders, or working with required fields, optional-value presence, and one-of fields.
Why use it?
Regular protobuf builders may detect a missing required field only when the program runs. These builders can make that mistake fail earlier during compilation.

Skill for Claude CodeCodex

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 skills/adamw7/tools/protogen
Any agent
npx skills add adamw7/tools --skill protogen
Clone the repo
git clone --depth 1 https://github.com/adamw7/tools

Made for: Claude Code, Codex.

Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,363 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 $0.00072 $0.01363
Opus 5 $0.00036 $0.00681
Sonnet 5 $0.00014 $0.00273
Haiku 4.5 $0.00007 $0.00136

Measured 2d ago against content hash 0133eadbf50e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

protogen 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 2d 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.

.claude/skills/protogen/SKILL.md · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Protogen Skill

Generate and use the compile-time-safe protobuf builders produced by code/protogen-maven-plugin. The point of this module is shift-left: stock protobuf builders only detect a missing required field at runtime (an UninitializedMessageException from build()), while the generated builder chain makes the same mistake fail to compile.

How the plugin is wired

The plugin runs after protobuf classes exist, so it consumes the compiled *.proto output and emits builder sources. Bind its code-generator goal to a generate-sources phase, point it at the packages holding the generated protobuf messages, and name an output package for the builders:

<plugin>
    <groupId>io.github.adamw7</groupId>
    <artifactId>protogen-maven-plugin</artifactId>
    <!-- Use the latest release: https://github.com/adamw7/tools/releases/latest -->
    <configuration>
        <generatedSourcesDir>${project.basedir}/target/generated-sources/</generatedSourcesDir>
        <pkgs>
            <param>io.github.adamw7.tools.code.protos</param>
        </pkgs>
        <outputpackage>io.github.adamw7.tools.code.builders</outputpackage>
    </configuration>
    <executions>
        <execution>
            <phase>generate-sources</phase>
            <goals>
                <goal>code-generator</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Mojo goal / parameters (CodeMojo, defaultPhase = GENERATE_SOURCES):

Parameter Property Meaning
generatedSourcesDir generatedsourcesdir Where the builder sources are written
pkgs pkgs Packages to scan for compiled protobuf messages
outputpackage outputpackage Package the generated builders go into

Add the output directory as a source root (e.g. build-helper-maven-plugin's add-source / add-test-source) so the builders are compiled with the rest of the module.

How the goal talks to its user

This module is the one place in the repository whose production code does not log through log4j2, and ProtogenArchitectureTest.pluginLogsThroughTheMojoLog holds it to that:

Read the full file on GitHub · 111 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2d ago First seen · 111 lines · 72 tokens per session scan A 0133eadbf50e

Subscribe to this mod's changes

protogen is a skill published in the GitHub repository adamw7/tools (11 stars, last pushed 4d ago), licensed MIT. It adds 72 tokens to every session and 1,363 once invoked, about $0.0004 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.

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