Validation

Before writing anything to the crontab, aias validates every scheduled prompt. This prevents broken cron entries from silently failing at runtime.

Validation Rules

1. Schedule Syntax

The schedule: value must be parseable as either a cron expression or a whenever DSL string.

aias validates this by evaluating a minimal whenever DSL fragment:

every '0 8 * * *' do
  command 'true'
end

Valid examples:

schedule: "0 8 * * *"
schedule: "@daily"
schedule: "every 1.day at 8:00am"
schedule: "every :monday at 9:00am"
schedule: "every 6.hours"

Invalid examples (fail with an error):

schedule: "every banana"     # not valid whenever DSL
schedule: "0 8 *"            # too few cron fields
schedule: ""                 # empty

2. Parameter Completeness

All parameters: keys must have non-nil, non-empty default values. Cron jobs run unattended — there is no interactive session to supply missing values.

# VALID — all parameters have defaults
parameters:
  topic: "Ruby news"
  format: "bullet points"

# INVALID — missing default
parameters:
  topic:           # nil value — rejected
  format: ""       # empty string — rejected

3. AIA Binary

The aia binary must be locatable. Two checks are performed in order; if either succeeds, the prompt passes:

1. Login-shell which — spawns a login shell and runs which aia. This is the normal path when the shell profile initialises the version manager (rbenv, rvm, asdf, etc.).

2. Fallback directory scan — if the login-shell check fails (common when rbenv init is not in the bash login profile), aias scans these directories for an executable named aia:

Directory	Manager
~/.rbenv/shims	rbenv
~/.rbenv/bin	rbenv
~/.rvm/bin	rvm
~/.asdf/shims	asdf
/usr/local/bin	Homebrew / manual
/usr/bin	system
/opt/homebrew/bin	Homebrew (Apple Silicon)

Only an executable file satisfies the check — a non-executable file at the path is ignored.

If aia is not found by either method, all prompts fail this check — no jobs are installed.

The check result is cached per Validator instance (shell spawn is expensive).

4. Prompts Directory

$AIA_PROMPTS_DIR must be set, exist, and be readable. This check happens before scanning, not per-prompt. If it fails, aias exits immediately with an error.

Validation Flow

For each prompt file with schedule: in frontmatter:
  1. Check schedule syntax        → error if invalid
  2. Check parameter defaults     → error per missing default
  3. Check aia binary             → error if not found (cached)

  If all checks pass  → prompt is included in install
  If any check fails  → prompt is skipped, warning to stderr

The crontab write happens only after all valid prompts have been collected. A mix of valid and invalid prompts is handled gracefully — valid ones are installed, invalid ones are skipped.

Seeing Validation Results

Use aias check to see validation results without modifying the crontab:

aias check

INVALID (would be skipped by update):
  bad_prompt: Schedule 'every banana': undefined method 'banana' for Integer

  bad_params: Parameter 'topic' has no default value (required for unattended cron execution)

Use aias dry-run to see what the valid prompts would generate:

aias dry-run