feat: hierarchical nested AGENTS.md loading

[marius-kilocode]

Implements hierarchical/nested AGENTS.md loading (plus optional ~/.kilocode/AGENTS.md) with guardrails.

• Extension: root (cwd) → active file directory rules.
• CLI: cwd rules (no active editor).
• Global: ~/.kilocode/AGENTS.md if present.
• Limits: max 6 files + max 10k chars; deterministic truncation.
• Adds preloaded notice so the model knows AGENTS rules are already in-context.

Fixes:

• Avoid passing activePath: undefined under exactOptionalPropertyTypes.

Files:

• src/core/prompts/sections/agent-rules.ts
• src/core/fs/find-up.ts
• src/core/prompts/sections/custom-instructions.ts

Tests:

• cd src && pnpm test core/prompts/sections/__tests__/
• cd cli && pnpm check-types

[changeset-bot]

🦋 Changeset detected

Latest commit: fb8d596

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
kilo-code	Patch

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[kiloconnect]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Overview

This PR introduces hierarchical loading of AGENTS.md files from nested directories, with proper size and file-count limits to prevent prompt overflow. The implementation is clean and well-structured.

Key observations:

• ✅ Proper error handling with try/catch blocks and null checks
• ✅ Size limits enforced (MAX_AGENT_RULE_FILES = 6, MAX_AGENT_RULE_CHARS = 10000)
• ✅ Symlink resolution with proper fallbacks
• ✅ Deduplication via seenPaths Set prevents duplicate content
• ✅ Global ~/.kilocode/AGENTS.md support with correct ordering
• ✅ Tests cover main scenarios (nesting, truncation, limits, fallback)
• ✅ Documentation updated to reflect removal of AGENT.md (singular) support

Files Reviewed (6 files)

• .changeset/nested-agents-md-rules.md - Changeset for the feature
• apps/kilocode-docs/docs/advanced-usage/migrating-from-cursor-windsurf.md - Documentation updates
• src/core/fs/find-up.ts - New utility for directory chain traversal
• src/core/prompts/sections/agent-rules.ts - Main implementation for nested AGENTS.md loading
• src/core/prompts/sections/custom-instructions.ts - Integration with existing custom instructions
• src/core/prompts/sections/__tests__/agent-rules.spec.ts - Test coverage
• src/core/prompts/sections/__tests__/custom-instructions.spec.ts - Removed obsolete tests for AGENT.md