cli-standards

A set of rules for designing command-line tools: programs operated by typing commands, flags, and parameters in a terminal.

In plain words
What is it for?
Use it when designing, implementing, or reviewing a command-line interface.
Why use it?
It helps keep command names, options, messages, colours, tables, and verbosity consistent and understandable.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/canonical/charm-tech/cli-standards
Any agent
npx skills add canonical/charm-tech --skill cli-standards
Clone the repo
git clone --depth 1 https://github.com/canonical/charm-tech

Made for: Claude Code, Codex.

Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,609 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00044 $0.01609
Opus 5 $0.00022 $0.00805
Sonnet 5 $0.00009 $0.00322
Haiku 4.5 $0.00004 $0.00161

Measured 2d ago against content hash ece6028854d3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cli-standards scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/engineering/cli-standards/SKILL.md · 209 lines

How it starts

The opening of the file, as written. The whole thing — 209 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Canonical CLI Standards

These standards define how Canonical CLI tools should look and behave. They originate from discussions with Canonical's senior tech leads and define best practice. All points must be strongly considered before contributing CLI code at Canonical.

For full do/don't examples of every rule, see examples.md.


Grammar + Vocabulary

Commands are verbs

Every command that acts on a primary object must be a verb (for example: install, refresh, login). Choose verbs that imply the object type they act on.

Commands are logically grouped

Group commands that act on the same object type or domain (for example: build lifecycle vs. store management).

Verb-noun form

When verbs alone are insufficient to distinguish objects, use verb-noun form:

snap set-quota

Listing secondary objects

Use the plural noun as shorthand instead of list-foobar:

snap services        # not: snap list-services
snap list            # for listing primary objects (snaps)

Showing state

  • Use status over show-status
  • Use foobar-status over show-foobar-status
  • Use foobar over show-foobar

Standard commands

Command Purpose
tool init Local initialisation
tool bootstrap Distributed initialisation (cluster, VM, cloud)
tool list Overview of all primary type instances
tool foobars Overview of all secondary type instances
tool show <id> Details for one primary instance
tool status Current tool state
tool start/stop Services, long-running processes
tool enable/disable Primary type, feature
tool get/set/unset Configuration
tool create-foo <id> Create secondary object
tool delete-foo <id> Delete secondary object
tool help Show help
tool version Show release version

Sublevels

At most one sublevel may be used. Alternatively, split into separate tools with associated names:

cmd cluster config --secret "$(cat secret.txt)"
# OR
cmd-cluster config --secret "$(cat secret.txt)"

Read the full file on GitHub · 209 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 209 lines · 44 tokens per session scan A ece6028854d3

Subscribe to this mod's changes

cli-standards is a skill published in the GitHub repository canonical/charm-tech (2 stars, last pushed 16d ago), licensed Apache-2.0. It adds 44 tokens to every session and 1,609 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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