feat(google-vertex): update model YAMLs [bot]

[models-bot]

Auto-generated by poc-agent for provider google-vertex.

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Note

Low Risk
Single metadata flag in a provider model YAML; no runtime or API behavior changes in this diff.

Overview
Adds prompt_caching to the features list for Vertex openai/gpt-oss-20b-maas, aligning capability metadata with the model’s existing cache_read_input_token_cost pricing entry.

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[github-actions]

/test-models

[harshiv-26]

Gateway test results

• Total: 8
• Passed: 6
• Failed: 0
• Validation failed: 0
• Errored: 0
• Skipped: 2
• Success rate: 100.0%

Provider	Model	Scenarios
google-vertex	openai/gpt-oss-20b-maas	success: params, structured-output:stream, params:stream, structured-output, reasoning:stream, reasoning skipped: tool-call, tool-call:stream

Successes (6)

google-vertex/openai/gpt-oss-20b-maas — params (success)

Output

The capital of France is Paris.

google-vertex/openai/gpt-oss-20b-maas — structured-output:stream (success)

Output

{"date":"Friday","name":"Science Fair","participants":["Alice","Bob"]}
VALIDATION: structured-output stream SUCCESS

google-vertex/openai/gpt-oss-20b-maas — params:stream (success)

Output

The capital of France is **Paris**.

google-vertex/openai/gpt-oss-20b-maas — structured-output (success)

Output

{"date":"Friday","name":"Science Fair","participants":["Alice","Bob"]}
VALIDATION: structured-output SUCCESS

google-vertex/openai/gpt-oss-20b-maas — reasoning:stream (success)

Output

**Step‑by‑step evaluation of**

\[
3^{3^{3^3}}
\]

---

## 1.  Clarify the order of operations  
Exponentiation is *right‑associative*.  
That means


... (truncated, 2497 chars omitted)

google-vertex/openai/gpt-oss-20b-maas — reasoning (success)

Output

**Step 1 – Understand the syntax**

Exponentiation is *right‑associative*.  
That means

a ^ b ^ c ≡ a ^ ( b ^ c )

So

3 ^ 3 ^ 3 ^ 3
≡
... (truncated, 2177 chars omitted)

</details>

</details>

<details>
<summary>Skipped (2)</summary>

**`google-vertex/openai/gpt-oss-20b-maas` — tool-call (skipped)**

<details><summary>Skip reason</summary>

Function calling fails in some regions with upstream error 'structure_info not used with HarmonyParser'

</details>

**`google-vertex/openai/gpt-oss-20b-maas` — tool-call:stream (skipped)**

<details><summary>Skip reason</summary>

Function calling fails in some regions with upstream error 'structure_info not used with HarmonyParser'

</details>

</details>