# Extend .mdc rule frontmatter with a model: field for cost-efficient agentic workflows

**URL:** <https://forum.cursor.com/t/extend-mdc-rule-frontmatter-with-a-model-field-for-cost-efficient-agentic-workflows/156812>\
**Category:** Feature Requests\
**Tags:** rules, anthropic\
**Created:** [April 6, 2026, 11:40am UTC](https://forum.cursor.com/t/extend-mdc-rule-frontmatter-with-a-model-field-for-cost-efficient-agentic-workflows/156812 "2026-04-06T11:40:29Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![user544](https://avatars.discourse-cdn.com/v4/letter/u/7993a0/32.png) [@user544](https://forum.cursor.com/u/user544)\
**Post date:** [April 6, 2026, 11:40am UTC](https://forum.cursor.com/t/extend-mdc-rule-frontmatter-with-a-model-field-for-cost-efficient-agentic-workflows/156812/1 "2026-04-06T11:40:30Z")

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### Feature request for product/service

Cursor IDE

### Describe the request

Add a `model:` field to `.cursor/rules` .mdc frontmatter so that **individual rules can declare which model should be used when executing the tasks they govern:**

```auto
---
description: Summarise notes files and write index entries
alwaysApply: false
model: claude-3-5-haiku-20241022
---

```

Cursor’s own fast / default aliases would work equally well as values, keeping it model-agnostic.

**Use case: note vault indexing**

I use Cursor to manage a ~650-file Obsidian markdown vault. A set of .mdc rules tell the AI how to index notes — reading each file and writing 2-3 sentence summaries to index files. This is pure summarisation: read → summarise → write. No architectural reasoning required.

When the agent runs a re-index pass it uses the default (full) model. Haiku is entirely sufficient for this and costs ~20× less. The only current workaround is manually switching models in the UI before starting - friction that’s easy to forget and impossible to enforce in a shared or automated context.

**Why it matters beyond this use case**

Most agentic workflows have a natural split between tasks that need deep reasoning and tasks that are bulk, low-complexity work (summarisation, formatting, extraction, boilerplate generation). Rules are already the mechanism for scoping behaviour - letting a rule declare its preferred model would make it possible to build cost-efficient, self-documenting agent workflows without manual model switching.

A `max_tokens:` field would be a natural companion for the same reason.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/colin/32/90452_2.png) [@Colin](https://forum.cursor.com/u/Colin)\
**Post date:** [April 7, 2026, 11:08am UTC](https://forum.cursor.com/t/extend-mdc-rule-frontmatter-with-a-model-field-for-cost-efficient-agentic-workflows/156812/4 "2026-04-07T11:08:50Z")

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Hey @user544!

Curious if [subagents](https://cursor.com/docs/subagents) would be the right fit for this! Have you tried them out?