feat(api-nodes): add Gemini 3.1 Flash-Lite model to LLM node

[bigcat88]

API Node PR Checklist

Scope

• Is API Node Change

Pricing & Billing

• Need pricing update
• No pricing update

If Need pricing update:

• Metronome rate cards updated
• Auto‑billing tests updated and passing

QA

• QA done
• QA not required

Comms

• Informed Kosinkadink

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR modifies the Gemini model configuration in comfy_api_nodes/nodes_gemini.py. The GeminiModel enum is removed and replaced with an explicit list of supported model strings in the UI schema. The default model is updated to gemini-3-1-pro. Model normalization mappings are added to handle aliases that map to canonical model names. Price calculation is expanded to include new model variants gemini-3-pro-preview, gemini-3.1-pro-preview, and gemini-3.1-flash-lite-preview. The price badge expression is updated to account for the expanded set of models.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding Gemini 3.1 Flash-Lite model support to the LLM node, which is the primary focus of the changeset.
Description check	✅ Passed	The description provides relevant context through an API Node PR checklist covering scope, pricing updates, QA status, and communications, which relates to the changeset's goals and requirements.

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Actionable comments posted: 1

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

comfy_api_nodes/nodes_gemini.py (1)

433-451: ⚠️ Potential issue | 🟠 Major

Re-add local prompt validation before building the request.

This method now goes straight from model normalization to GeminiPart(text=prompt), so empty or whitespace-only prompts reach the remote API instead of failing fast in-node. That is a behavior regression unrelated to the model addition and makes API failures harder to diagnose.

Suggested change

     ) -> IO.NodeOutput:
+        validate_string(prompt, strip_whitespace=True, min_length=1)
         if model == "gemini-3-pro-preview":
             model = "gemini-3.1-pro-preview"  # model "gemini-3-pro-preview" will be soon deprecated by Google
         elif model == "gemini-3-1-pro":
             model = "gemini-3.1-pro-preview"
         elif model == "gemini-3-1-flash-lite":
             model = "gemini-3.1-flash-lite-preview"

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@comfy_api_nodes/nodes_gemini.py` around lines 433 - 451, In execute, re-add
local validation for the prompt before constructing parts/GeminiPart: trim
prompt (and optionally system_prompt) and if it's empty or only whitespace, fail
fast by raising a clear exception or returning an error NodeOutput instead of
calling the remote API; insert this check immediately before the line that
creates parts: list[GeminiPart] = [GeminiPart(text=prompt)] so empty/whitespace
prompts are caught in-node.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@comfy_api_nodes/nodes_gemini.py`:
- Around line 287-295: The dropdown options list should not advertise
"gemini-3-pro-preview" since execute() always remaps that value to
"gemini-3.1-pro-preview"; remove "gemini-3-pro-preview" from the options array
metadata so users can't select it, and keep the legacy ID only in the
compatibility/remapping logic inside the execute() method (where you detect and
upgrade the old ID) to preserve backwards compatibility.

---

Outside diff comments:
In `@comfy_api_nodes/nodes_gemini.py`:
- Around line 433-451: In execute, re-add local validation for the prompt before
constructing parts/GeminiPart: trim prompt (and optionally system_prompt) and if
it's empty or only whitespace, fail fast by raising a clear exception or
returning an error NodeOutput instead of calling the remote API; insert this
check immediately before the line that creates parts: list[GeminiPart] =
[GeminiPart(text=prompt)] so empty/whitespace prompts are caught in-node.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 14defb14-050c-4baa-abc5-bf17ab4f8074

📥 Commits

Reviewing files that changed from the base of the PR and between 3b93d5d and df8a8a7.

📒 Files selected for processing (1)

• comfy_api_nodes/nodes_gemini.py