The utilities Skill — Shell Recipes Without External Dependencies
How the utilities skill provides a library of native shell one-liners — from hashing to SSH remote execution — organized into fragments so only the relevant code loads.
An agent that reaches for an MCP server to generate a UUID or format a date is using a sledgehammer for a nail. The utilities skill addresses this by providing a library of shell recipes built entirely from tools available on macOS and Linux by default: bash, python3, openssl, and jq. No external MCP server required.
The skill covers more than a dozen utility domains: date/time operations, system information, cryptographic operations, encoding, text transformation, input validation, JSON manipulation, number and color formatting, Datarim file synchronization, Google Analytics 4 Admin API, SSH remote execution, session recovery, keyword linting, and git diff parsing. Each domain lives in its own fragment file.
Fragment routing
The entry file is intentionally short. An agent that needs to hash a string loads crypto.md. One that needs to convert a date to epoch loads datetime.md. One parsing a git diff for added and removed lines loads git-diff-parsing.md, which includes the canonical filter chain for separating real additions and removals from hunk-context noise. Loading the full 500-line library when only a single one-liner is needed wastes context tokens — the split keeps idle cost near zero.
What the fragments contain
The crypto.md fragment covers SHA-256, SHA-512, and MD5 hashing, UUID generation, random string production, and password generation — all via openssl or python3. The encoding.md fragment provides Base64 encode and decode plus URL encoding. The text-transform.md fragment handles camelCase, snake_case, kebab-case, PascalCase conversion, and slug generation from arbitrary strings.
The ssh-deploy.md fragment solves a specific practical problem: running scripts on remote servers via SSH without heredoc corruption. The canonical pattern encodes the script in Base64 locally, transfers it, and decodes on the remote end — a technique that survives quoting and escaping problems that heredoc approaches regularly encounter.
Recovery and synchronization
Two fragments address operational scenarios outside typical development work. recovery.md provides recipes for recovering lost runtime files from a compacted session context — a disaster recovery procedure when session history has been truncated. datarim-sync.md covers synchronizing framework files between the local $HOME/.claude/ installation and the Datarim repository, keeping both in alignment without manual copying.
The utilities skill sits in the background of most Datarim workflows. The systematic-debugging skill draws on its shell recipes for diagnostic instrumentation. The using-git-worktrees skill uses git-level shell commands from the same family. For the broader context, see what is Datarim.