docs(instructions): explain conditional custom instruction loading

docs/scripts.md

@@ -34,7 +34,7 @@ Run scripts from the repository root. PowerShell and Bash commands have equivale
 
 Prompt KPIs estimate tokens as UTF-8 bytes divided by four, using the larger shell package per client. Skill metadata counts `SKILL.md` frontmatter outside rule skills; the rule catalog counts all generated rule entry files but excludes references, so it measures the available catalog size rather than rules loaded in a typical session; agent metadata counts frontmatter for Claude and `name`/`description` for Codex. All metrics fail CI above baseline +10%; permanent context also warns above 10,000 tokens and fails above 15,000 tokens. The baseline covers the retained skill catalog. Project-specific instructions, external plugin prompt bodies, and live MCP/tool schemas are not measured.
 
-Custom instructions are read before generated rules, skills, and plugins. They remain under `~/.my-ai-configuration/instructions/`, so installation and update scripts never manage or reset them.
+Custom instructions remain under `~/.my-ai-configuration/instructions/`; installation and update scripts never reset their contents. Only clients with a nonempty instruction file receive a startup rule in their installed `AGENTS.md` or `CLAUDE.md`. That rule requires immediate loading before any response or task work and keeps the instructions active throughout the session, including after compaction. Adding or removing instructions refreshes the rule in an existing installation; empty or missing instruction files leave no rule. Generated packages contain no personal instruction rule. Changes apply when the client next loads its global instructions.
 To undo an added instruction, pass the same text to `remove-instruction` with `-Client`/`--client` and `-Instruction`/`--instruction`. It removes the last exact matching block per selected client and preserves other text. A missing match leaves the file unchanged.
 
 Credential commands currently require PowerShell and Windows Credential Manager, including their Bash wrappers. Use `~/.my-ai-configuration/bin/with-credential.ps1` or `.sh` to run a tool with a stored key available only in that child process. The key must be a valid environment-variable name; its value is never written to configuration.