Dev MCP

my-extension/deployment/src/main/resources/META-INF/quarkus-skill.md

name: "My Extension"
description: "A concise description of what this extension does"
artifact: ${project.groupId}:${project.artifactId}:${project.version}
metadata:
  guide: "https://quarkus.io/guides/my-extension"
  categories:
  - "web"

### Data Access

- Inject `MyClient` with `@Inject` — it is an `@ApplicationScoped` CDI bean.
- Use `client.query("...")` for read operations.
- Always wrap write operations in `@Transactional`.

### Testing

- Use `@QuarkusTest` — Dev Services starts a backing service automatically.
- Inject `MyClient` in tests for direct assertions.

### Common Pitfalls

- Do NOT create `MyClient` manually with `new` — always let CDI inject it.
- Do NOT set the connection URL without a `%prod.` profile prefix — this disables Dev Services.

---
name: quarkus-my-extension
description: "A brief description of the extension from quarkus-extension.yaml"
license: Apache-2.0
metadata:
  guide: https://quarkus.io/guides/my-extension
  categories: "web, data"
---

### Data Access
...

### Available Dev MCP Tools

| Tool | Description | Parameters |
|------|-------------|------------|
| `quarkus-my-extension_getData` | Get current status | — |
| `quarkus-my-extension_updateValue` | Update a value | `name` (required): The name, `value` (required): The new value |

@DevMcpBuildTimeTool(name = "updateProperty", (1)
    description = "Update a configuration property", (2)
    params = {
        @DevMcpParam(name = "name", description = "The property name"), (3)
        @DevMcpParam(name = "value", description = "The new value")
    })
public class ConfigurationProcessor {
    // ...
}

public class MyExtensionRPCService {

    @JsonRpcDescription("Update a specific logger's level in this Quarkus application") (1)
    public JsonObject updateLogLevel(
            @JsonRpcDescription("The logger name as defined in the logging implementation") String loggerName,
            @JsonRpcDescription("The new log level") String levelValue) { (2)
        // implementation…
    }
}

@BuildStep
JsonRPCProvidersBuildItem registerRpcService() { (1)
    return new JsonRPCProvidersBuildItem(MyExtensionRPCService.class); (2)
}

@BuildStep(onlyIf = IsLocalDevelopment.class)
BuildTimeActionBuildItem createBuildTimeActions() {
    BuildTimeActionBuildItem actions = new BuildTimeActionBuildItem();
    actions.actionBuilder()
            .methodName("updateProperty")
            .description("Update a configuration/property in the Quarkus application")   (1)
            .parameter("name", "The name of the configuration/property to update")       (2)
            .parameter("value", "The new value for the configuration/property")
            .function(map -> {
                Map<String, String> values = Collections.singletonMap(
                        map.get("name"), map.get("value"));
                updateConfig(values);
                return true;
            })
            .build();
    return actions;
}

footerPageBuildItem.addBuildTimeData(
    "jokes",
    jokesBuildItem.getJokes(),
    "Some funny jokes that the user might enjoy"
);

footerPageBuildItem.addBuildTimeData(
    "jokes",
    jokesBuildItem.getJokes(),
    "Some funny jokes that the user might enjoy",
    true
);

@BuildStep(onlyIf = IsLocalDevelopment.class)
BuildTimeActionBuildItem createBuildTimeActions() {
    BuildTimeActionBuildItem item = new BuildTimeActionBuildItem(); (1)
    item.actionBuilder() (2)
            .methodName("getMyRecordedValue")
            .description("A well‑thought‑out description") (3)
            .runtime(runtimeValue) (4)
            .build();
    return item;
}