Development record

.abcd/development/brief/05-internals/03-configuration.md:1553 says SHELL's injected block costs about 2k tokens for the bundled registry. `*SHELL` through `abcd hook prompt-router --json` in a repository with no `.abcd/guard.json` injects 33,320 bytes, about 8,000 tokens at four bytes a token, in 63 rules. internal/core/guard/defaults/guard.json holds 60 entries; the other three rules name entries defined in code.