Azure SDK for Java is a collection of Java libraries that let applications connect to and manage Azure services. Java developers use its client libraries to consume services and its management libraries to configure Azure resources. The catalogue add-ons support development with these libraries.
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.
npx agentmods add skills/azure/azure-sdk-for-java/union-type-wrappersnpx skills add Azure/azure-sdk-for-java --skill union-type-wrappersgit clone --depth 1 https://github.com/Azure/azure-sdk-for-javaWrote 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/skills/azure/azure-sdk-for-java/union-type-wrappers)<a href="https://agentmods.dev/skills/azure/azure-sdk-for-java/union-type-wrappers"><img src="https://agentmods.dev/badge/skills/azure/azure-sdk-for-java/union-type-wrappers.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 | $0.00049 | $0.03164 |
| Opus 5 | $0.00024 | $0.01582 |
| Sonnet 5 | $0.00010 | $0.00633 |
| Haiku 4.5 | $0.00005 | $0.00316 |
Grade A, and why
union-type-wrappers 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 337 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Union Type Wrappers for Generated Java Models
When the Java codegen encounters a TypeSpec union type (e.g. string | SomeModel), it emits the property as BinaryData. This skill replaces public BinaryData accessors with typed setters and getters for each union variant, following the same pattern established for PromptAgentDefinition.toolChoice.
Preconditions
- You must be in a Java SDK module directory containing
tsp-location.yamlandpom.xml. - TypeSpec sources must be available in
TempTypeSpecFiles/. If missing, runtsp-client syncfirst. - The project must compile before starting.
Important: BinaryData.writeTo(JsonWriter) semantics
Understanding how BinaryData writes to JSON is critical for choosing the correct factory method:
| Factory method | Content type | writeTo(JsonWriter) calls |
JSON output |
|---|---|---|---|
BinaryData.fromString("auto") |
StringContent |
jsonWriter.writeString("auto") |
"auto" (quoted) |
BinaryData.fromObject("auto") |
SerializableContent |
jsonWriter.writeRawValue(...) |
"auto" (quoted via Jackson) |
BinaryData.fromObject(42.0) |
SerializableContent |
jsonWriter.writeRawValue(...) |
42.0 (raw) |
BinaryData.fromObject(true) |
SerializableContent |
jsonWriter.writeRawValue(...) |
true (raw) |
BinaryData.fromObject(jsonSerializable) |
SerializableContent |
jsonWriter.writeRawValue(...) |
{...} (JSON object via JacksonAdapter) |
Key: JacksonAdapter has special handling for JsonSerializable types — BinaryData.fromObject() and BinaryData.toObject() both work correctly with Azure JsonSerializable models.
Setter factory method rules
| Union variant | Factory method | Reason |
|---|---|---|
| String value (ID, enum token) | BinaryData.fromString(value) |
Writes as JSON string via writeString() |
| Numeric / boolean primitive | BinaryData.fromObject(value) |
Writes as raw JSON value |
Azure JsonSerializable model |
BinaryData.fromObject(value) |
JacksonAdapter handles serialization |
| Stainless (openai-java) type | BinaryData.fromObject(value) |
Jackson handles serialization |
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.
- 5d ago First seen · 337 lines · 49 tokens per session scan A 7b00c978918d
union-type-wrappers is a skill published in the GitHub repository Azure/azure-sdk-for-java (2,566 stars, last pushed today), licensed MIT. It adds 49 tokens to every session and 3,164 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 2026-08-30.
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