cli-logging-ux

CLI Logging UX expert persona

CLI Logging & Developer Experience

Decision framework

Apply these three tests to every piece of user-facing output. If a message fails any test, redesign it.

1. The "So What?" Test

Every warning must answer: what should the user do about this?

# Fails — not actionable, user can't do anything
Sub-skill 'my-skill' from 'my-package' overwrites existing skill

# Passes — tells the user exactly what to do
Skipping my-skill — local file exists (not managed by APM). Use 'apm install --force' to overwrite.

If the user can't act on it, it's not a warning — it's noise. Demote to --verbose or remove.

2. The Traffic Light Rule

Use color semantics consistently. Never use a warning color for an informational state.

Color	Helper	Meaning	When to use
Green	_rich_success()	Success / completed	Operation finished as expected
Yellow	_rich_warning()	User action needed	Something requires user decision
Red	_rich_error()	Error / failure	Operation failed, cannot continue
Blue	_rich_info()	Informational	Status updates, progress, summaries
Dim	_rich_echo(color="dim")	Secondary detail	Verbose-mode details, grouping headers

3. The Newspaper Test

Can the user scan output like headlines? Top-level = what happened. Details = drill down.

# Bad — warnings break the visual flow between status and summary
[checkmark] package-name
[warning] something happened
[warning] something else happened
  [tree] 3 skill(s) integrated

# Good — clean tree, diagnostics at the end
[checkmark] package-name
  [tree] 3 skill(s) integrated

── Diagnostics ──
  [warning] 2 skills replaced by a different package (last installed wins)
    Run with --verbose to see details

Inline output vs deferred diagnostics

Use inline output for:

• Success confirmations (_rich_success)
• Progress updates (_rich_info with indented └─ prefix)
• Errors that halt the current operation (_rich_error)

Use DiagnosticCollector for:

• Warnings that apply across multiple packages (collisions, overwrites)
• Issues the user should know about but that don't stop the operation
• Anything that would repeat N times in a loop

# Bad — inline warning repeated per file, clutters output
for file in files:
    if collision:
        _rich_warning(f"Skipping {file}...")

# Good — collect during loop, render grouped summary at the end
for file in files:
    if collision:
        diagnostics.skip(file, package=pkg_name)

# Later, after the loop:
if diagnostics.has_diagnostics:
    diagnostics.render_summary()

DiagnosticCollector categories: skip() for collisions, overwrite() for cross-package replacements, warn() for general warnings, error() for failures.

Console helper conventions

Always use the helpers from apm_cli.utils.console — never raw print() or bare click.echo().

Emojis are banned. Never use emoji characters anywhere in CLI output — not in messages, symbols, help text, or status indicators. Use ASCII text symbols exclusively via STATUS_SYMBOLS.

from apm_cli.utils.console import (
    _rich_success, _rich_error, _rich_warning, _rich_info, _rich_echo
)

_rich_success("Installed 3 APM dependencies")        # green, bold
_rich_info("  └─ 2 prompts integrated → .github/prompts/")  # blue
_rich_warning("Config drift detected — re-run apm install")  # yellow
_rich_error("Failed to download package")              # red
_rich_echo("    [pkg-name]", color="dim")              # dim, for verbose details

Use STATUS_SYMBOLS dict with symbol= parameter for consistent ASCII prefixes:

_rich_info("Starting operation...", symbol="gear")     # renders as "[*] Starting operation..."

Output structure pattern

Follow this visual hierarchy for multi-package operations:

[checkmark] package-name-1                      # _rich_success — download/copy ok
  [tree] 2 prompts integrated → .github/prompts/     # _rich_info — indented summary
  [tree] 1 skill(s) integrated → .github/skills/
[checkmark] package-name-2
  [tree] 1 instruction(s) integrated → .github/instructions/

── Diagnostics ──                         # Only if diagnostics.has_diagnostics
  [warning] N files skipped — ...                   # Grouped by category
    Run with --verbose to see details

Installed 2 APM dependencies              # _rich_success — final summary

Content-awareness principle

Before reporting changes, check if anything actually changed. Don't report no-ops.

# Bad — always copies and reports, even when content is identical
shutil.rmtree(target)
shutil.copytree(source, target)
_rich_info(f"  └─ Skill updated")

# Good — skip when content matches
if SkillIntegrator._dirs_equal(source, target):
    continue  # Nothing changed, nothing to report

CommandLogger Architecture

APM is a large and growing CLI with 10+ commands, 8+ integrators, and dozens of output sites. The logging architecture enforces Separation of Concerns: commands declare what happened; the logger decides how to render it. This keeps output consistent, testable, and evolvable without shotgun surgery across command files.

The three layers

┌─────────────────────────────────────────────────────┐
│  Command layer  (install.py, pack.py, audit.py …)   │
│  Calls: logger.success(), logger.tree_item(), …      │
│  NEVER calls: _rich_*, click.echo(), print()         │
├─────────────────────────────────────────────────────┤
│  Logger layer   (command_logger.py)                  │
│  CommandLogger ← InstallLogger, future subclasses    │
│  Owns: verbose gating, symbol choice, indentation    │
│  Delegates to: _rich_* helpers                       │
├─────────────────────────────────────────────────────┤
│  Rendering layer (console.py)                        │
│  _rich_echo, _rich_success, _rich_error, …           │
│  Owns: Rich/colorama fallback, color, STATUS_SYMBOLS │
└─────────────────────────────────────────────────────┘

Changes to output style (colors, symbols, indentation) happen in the logger or rendering layer only — command code is untouched. New output patterns (e.g. a tree sub-item, a package metadata line) become new logger methods, not ad-hoc format strings in commands.

Base class: CommandLogger

src/apm_cli/core/command_logger.py — base for all commands.

Method	Purpose	When to use
start(msg, symbol=)	Operation start	Beginning of a command
progress(msg, symbol=)	Status update with [i] prefix	Mid-operation phase changes
success(msg, symbol=)	Green success	Operation completed
warning(msg, symbol=)	Yellow warning	User action needed
error(msg, symbol=)	Red error	Operation failed
verbose_detail(msg)	Dim text, verbose-only	Internal details (paths, hashes)
tree_item(msg)	Green text, no symbol prefix	└─ sub-items under a package
package_inline_warning(msg)	Yellow text, verbose-only	Per-package diagnostic hints
dry_run_notice(msg)	[dry-run] prefix	Dry-run explanation
auth_step(step, success, detail)	Auth resolution step	Verbose auth tracing
render_summary()	Render DiagnosticCollector	End of command

Subclass: InstallLogger(CommandLogger)

Install-specific phases. Commands that don't need these use CommandLogger directly.

Method	Purpose	Output
validation_start(count)	Start validation	[*] Validating N package(s)...
validation_pass(name, present)	Package OK	[+] name or name (already in apm.yml)
validation_fail(name, reason)	Package bad	[x] name -- reason
resolution_start(count, lockfile)	Start resolution	Context-aware install/update message
download_complete(name, ref=, sha=, cached=)	Package installed	[+] name #tag @sha or (cached)
download_failed(name, error)	Download error	[x] name -- error
lockfile_entry(key, ref=, sha=)	Lockfile verbose line	key: locked at sha / pinned to ref / omitted
package_auth(source, token_type=)	Auth source verbose	Auth: source (type)
package_type_info(label)	Package type verbose	Package type: label
install_summary(apm, mcp, errors)	Final summary	Installed N APM dependencies.

When to add a new logger method

If a command needs a new output pattern (new indentation level, new semantic meaning, new verbose gate), add a method to CommandLogger or a subclass. Signs you need a new method:

• You're writing _rich_echo(f" Something: {value}", color="dim") in a command file
• You're checking if logger.verbose: before calling _rich_echo in a command
• You're formatting a string with specific indentation that other commands might reuse
• Multiple commands emit the same kind of line (e.g., file lists, auth info)

Rule: No direct _rich_* in commands

Command functions must NOT call _rich_info(), _rich_error(), etc. directly. Use logger.progress(), logger.error(), etc. instead. The _rich_* helpers are internal to the logger and rendering layers.

Exception: Rich tables and panels for display (not lifecycle logging) may use console.print() directly — these are data presentation, not status reporting.

Rule: Every command gets a CommandLogger

Every Click command function must instantiate a CommandLogger (or subclass) and pass it to helpers:

@cli.command()
@click.option("--verbose", "-v", is_flag=True)
@click.option("--dry-run", is_flag=True)
def my_command(verbose, dry_run):
    logger = CommandLogger("my-command", verbose=verbose, dry_run=dry_run)
    logger.start("Starting operation...")
    _do_work(logger=logger)
    logger.render_summary()

Rule: Verbose gating lives in the logger

Never check if verbose: in command code. Use methods that gate internally:

# Bad — manual verbose check in command
if verbose:
    _rich_echo(f"    Auth: {source}", color="dim")

# Good — logger handles the gate
logger.package_auth(source, token_type)  # No-ops when not verbose
logger.verbose_detail(f"    Path: {path}")  # No-ops when not verbose

DiagnosticCollector integration

Access via logger.diagnostics (lazy-initialized). The collector owns the collect-then-render lifecycle:

# During operation — collect
diagnostics.skip(file, package=pkg_name)          # Collision
diagnostics.overwrite(file, package=pkg_name)     # Cross-package replacement
diagnostics.error(msg, package=pkg_name)          # Failure
diagnostics.auth(msg, package=pkg_name)           # Auth issue

# Query during operation (e.g., for inline verbose hints)
count = diagnostics.count_for_package(pkg_name, category="collision")
if count > 0:
    logger.package_inline_warning(f"    [!] {count} files skipped")

# After operation — render grouped summary
logger.render_summary()  # Delegates to diagnostics.render_summary()

Visual hierarchy contract

Multi-package operations follow this tree structure:

  [+] package-name #v1.0 @b0cbd3df                    # download_complete
      Auth: git-credential-fill (oauth)                # package_auth (verbose)
      Package type: Skill (SKILL.md detected)          # package_type_info (verbose)
    └─ 3 skill(s) integrated -> .github/skills/        # tree_item
    └─ 1 prompt integrated -> .github/prompts/         # tree_item
      [!] 2 files skipped (local files exist)          # package_inline_warning (verbose)
  [+] another-package (cached)                         # download_complete

── Diagnostics ──                                      # render_summary
  [!] 2 files skipped -- local files exist             # Grouped by category
    Use 'apm install --force' to overwrite

[*] Installed 2 APM dependencies.                      # install_summary

Key rules:

• [+] package lines are the top-level anchors (green, no indent beyond 2-space)
• Verbose metadata (Auth, Package type) uses 4-space indent, dim color
• Tree items (└─) use 4-space indent, green color, no symbol prefix
• Inline warnings use 4-space indent, yellow color, verbose-only
• Diagnostics summary appears AFTER all packages, not inline (except verbose hints)

Scaling guidance

As the CLI grows, this architecture scales by:

• New commands: Instantiate CommandLogger, use existing methods. Add subclass only if the command has distinct phases (like InstallLogger).
• New output patterns: Add methods to CommandLogger. Every command benefits.
• New integrators: Accept diagnostics= param, push to collector. No direct output.
• Theme changes: Modify rendering layer (console.py). Zero command changes.
• Testing: Mock CommandLogger in tests to assert semantic calls without parsing output strings.

Anti-patterns

1. Warning for non-actionable state — If the user can't do anything about it, use _rich_info or defer to --verbose, not _rich_warning.

2. Inline warnings in loops — Use DiagnosticCollector to collect, then render a grouped summary after the loop.

3. Missing diagnostics parameter — When calling integrators, always pass diagnostics=diagnostics so warnings route to the deferred summary.

4. No emojis, ever — Emojis are completely banned from all CLI output. Use ASCII text symbols from STATUS_SYMBOLS exclusively. This applies to messages, help text, status indicators, and table titles.

5. Inconsistent symbols — Always use STATUS_SYMBOLS dict with symbol= param, not inline characters.

6. Walls of text — Use Rich tables for structured data, panels for grouped content. Break up long output with visual hierarchy (indentation, └─ tree connectors).

7. Direct _rich_* calls in commands — Use logger.start(), logger.progress(), logger.tree_item() etc. The _rich_* helpers are internal to CommandLogger and console.py. Adding a _rich_echo call in a command file is a SoC violation.

8. Manual if verbose: checks — Use logger.verbose_detail(), logger.package_auth(), or other verbose-gated methods. The logger owns the gate.

9. Manual if dry_run: checks — Use logger.should_execute or logger.dry_run_notice().

10. Format strings for indentation in commands — Don't write f" Auth: {source}" in command code. Use logger.package_auth(source) which owns the indent level. When a new indentation pattern is needed, add a method to CommandLogger.

11. Re-creating shared objects per iteration — Expensive objects like AuthResolver should be created once before loops and reused per-package. The logger and diagnostics collector are already singletons per command invocation.

12. Using logger.progress() for tree sub-items — progress() adds a [i] symbol prefix. Tree continuation lines (└─) should use logger.tree_item() which renders with no symbol.