diff --git a/docs/docs.json b/docs/docs.json
index 21d22ae5..94dcdf0e 100644
--- a/docs/docs.json
+++ b/docs/docs.json
@@ -129,6 +129,7 @@
"rfds/next-edit-suggestions",
"rfds/additional-directories",
"rfds/custom-llm-endpoint",
+ "rfds/model-config-category",
{
"group": "v2 Draft",
"expanded": true,
diff --git a/docs/rfds/model-config-category.mdx b/docs/rfds/model-config-category.mdx
new file mode 100644
index 00000000..376b6c98
--- /dev/null
+++ b/docs/rfds/model-config-category.mdx
@@ -0,0 +1,83 @@
+---
+title: "Model Config Option Category"
+---
+
+- Author(s): [anna239](https://github.com/anna239)
+
+## Elevator pitch
+
+Add a new `model_config` category to session configuration options, so that agents can expose model-related parameters (context size, speed/quality trade-offs, etc) and clients can group them alongside the main model selector in the UI.
+
+## Status quo
+
+The `category` field on `SessionConfigOption` currently supports three values: `mode`, `model`, and `thought_level`. This works well when the model is a single selector, but some agents expose many model configurations — context window size, speed tier, and similar settings that logically belong next to the model picker.
+
+## What we propose to do about it
+
+Add a `model_config` variant to `SessionConfigOptionCategory`.
+
+Agents tag any model-related parameters with `"category": "model_config"`, and clients render them near the primary `model` selector — for example as secondary controls within a model-picker popover or panel.
+
+### Relationship to `thought_level`
+
+Once `model_config` exists, `thought_level` is semantically a special case of a model configuration parameter. We keep `thought_level` as-is for backward compatibility — existing clients already handle it — but new model-related options should use `model_config`.
+
+## Shiny future
+
+Agents expose rich, parameterized model configurations over ACP.
+
+## Implementation details and plan
+
+### JSON format
+
+An agent declares model-config options in `configOptions`:
+
+```json
+{
+ "configOptions": [
+ {
+ "id": "model",
+ "name": "Model",
+ "category": "model",
+ "type": "select",
+ "currentValue": "sonnet-4.5",
+ "options": [
+ { "value": "sonnet-4.5", "name": "Sonnet 4.5" },
+ { "value": "opus-4.6", "name": "Opus 4.6" }
+ ]
+ },
+ {
+ "id": "context_size",
+ "name": "Context Size",
+ "category": "model_config",
+ "type": "select",
+ "currentValue": "200k",
+ "options": [
+ { "value": "200k", "name": "200K" },
+ { "value": "1m", "name": "1M" }
+ ]
+ },
+ {
+ "id": "fast_mode",
+ "name": "Fast Mode",
+ "category": "model_config",
+ "type": "boolean",
+ "currentValue": false
+ }
+ ]
+}
+```
+
+### Client behavior
+
+- Clients SHOULD render `model_config` options near the `model` selector (e.g., in the same popover or panel).
+- Clients that do not recognize the category MUST handle it gracefully per the existing spec — the option still renders, just without special placement.
+- No new client capability negotiation is needed.
+
+### Should `thought_level` move under `model_config`?
+
+Not now. Existing clients already handle `thought_level`, so changing its semantics would be a breaking change. New model-related parameters should use `model_config`; `thought_level` remains for backward compatibility.
+
+## Revision history
+
+- 2026-04-08: Initial proposal
diff --git a/docs/rfds/updates.mdx b/docs/rfds/updates.mdx
index 4c9b9963..2ff11f82 100644
--- a/docs/rfds/updates.mdx
+++ b/docs/rfds/updates.mdx
@@ -6,6 +6,20 @@ rss: true
This page tracks lifecycle changes for ACP Requests for Dialog. For broader ACP announcements, see [Updates](/updates).
+
+## model_config Category RFD moves to Draft
+
+The RFD for the `model_config` category been moved to Draft stage. Please review the [RFD](/rfds/model-config-category) for more information on the current proposal and provide feedback before the feature is stabilized.
+
+
+
+
+## v2 Prompting RFD moves to Draft
+
+The RFD for how the prompt lifecycle will work in v2 of the protocol been moved to Draft stage. Please review the [RFD](/rfds/v2/prompt) for more information on the current proposal and provide feedback before the feature is stabilized.
+
+
+
## session/close RFD moves to Completed