Feature Request: Opt-out directive for AGENTS.md auto-loading

[john-taylor-ssi]

Problem

In multi-folder workspaces with many library dependencies (e.g., 27+ folders), all AGENTS.md files from workspace roots are automatically loaded into every thread context. This consumes tokens unnecessarily when only working in a subset of the codebase.

Current Behavior

• AGENTS.md files in workspace roots and parent directories are always included
• Subtree AGENTS.md files load when reading files in that subtree (this is good)
• No way to opt-out specific AGENTS.md files from auto-loading

Proposed Solution

Support a frontmatter directive that prevents auto-loading:

---
autoload: false
---
# Library-specific guidance
This file is only included when explicitly @-mentioned

Use Case

• Large workspaces with main project + multiple dependency libraries
• Each library has its own AGENTS.md but most threads only touch the main project
• Current workarounds (renaming files, reducing workspace folders) are cumbersome

Alternatives Considered

• Renaming AGENTS.md files to prevent auto-inclusion (breaks intended functionality)
• Reducing workspace folders (loses multi-project benefits)
• Using glob frontmatter in a single AGENTS.md (doesn't address root-level auto-loading)