modify skill and plugin

plugins/agents-md-management/skills/agents-md-improver/references/update-guidelines.md

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+# AGENTS.md Update Guidelines
+
+## Core Principle
+
+Only add information that will genuinely help future Codex sessions. The context window is precious; every line must earn its place.
+
+## What To Add
+
+### Commands and Workflows Discovered
+
+```markdown
+## Commands
+
+`npm run build` - Production build.
+`npm run lint` - ESLint check required before handoff.
+```
+
+Why: saves future sessions from rediscovering commands.
+
+### Gotchas and Non-Obvious Patterns
+
+```markdown
+## Gotchas
+
+- Tests must run sequentially because they share a local database.
+- Regenerate API clients with `npm run codegen` after editing OpenAPI files.
+```
+
+Why: prevents repeated debugging.
+
+### Package Relationships
+
+```markdown
+## Architecture
+
+- `packages/api` owns route handlers; `packages/ui` must call it through the shared client.
+```
+
+Why: captures relationships that are not obvious from filenames.
+
+### Testing Approaches That Worked
+
+```markdown
+## Testing
+
+- API endpoint tests use `tests/helpers/request.ts`; avoid ad hoc server setup.
+```
+
+Why: establishes known-good patterns.
+
+### Configuration Quirks
+
+```markdown
+## Environment
+
+- `NEXT_PUBLIC_*` variables must be set at build time.
+```
+
+Why: environment details often waste time when omitted.
+
+## What Not To Add
+
+### Obvious Code Info
+
+Bad:
+
+```markdown
+The `UserService` class handles user operations.
+```
+
+The class name already says that.
+
+### Generic Best Practices
+
+Bad:
+
+```markdown
+Always write tests for new features.
+Use meaningful variable names.
+```
+
+Add only project-specific rules.
+
+### One-Off Fixes
+
+Bad:
+
+```markdown
+We fixed a bug where the login button did not work.
+```
+
+Unless the lesson is durable, leave it out.
+
+### Verbose Explanations
+
+Bad:
+
+```markdown
+The authentication system uses JWT tokens. JWT means JSON Web Token...
+```
+
+Good:
+
+```markdown
+Auth: JWT HS256 tokens in `Authorization: Bearer <token>`.
+```
+
+## Diff Format
+
+For each suggested change:
+
+```markdown
+### Update: ./AGENTS.md
+
+**Why:** The build command exists but was missing from project instructions.
+
+```diff
++## Commands
++
++`npm run build` - Production build.
+```
+```
+
+## Validation Checklist
+
+- Each addition is project-specific.
+- No generic advice or obvious info.
+- Commands are verified against the repo.
+- File paths are accurate.
+- The wording is concise.
+- A new Codex session would benefit from the line.