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Workflow Expressions

Use {{expr:...}} in step params to transform data between steps — extract JSON fields, format timestamps, manipulate strings.

Config

# .factorly/factorly.yaml
tools:
  daily.summary:
    type: workflow
    description: Fetch today's calendar events and post a summary to Slack
    parameters:
      - name: channel
        default: "#general"
    steps:
      - tool: google-calendar.list_events
        params:
          calendarId: primary
          timeMin: "{{expr:now()}}"
          timeMax: "{{expr:now('24h')}}"
          maxResults: "10"
        store: events

      - tool: slack.post_message
        if: "jsonpath(events, '$.items') != ''"
        params:
          channel: "{{channel}}"
          text: "{{expr:concat('You have ', len(events), ' events today')}}"

Run it

factorly call daily.summary
factorly call daily.summary --channel '#engineering'

More examples

Extract and transform JSON

steps:
  - tool: api.get_user
    params:
      id: "{{user_id}}"
    store: user

  - tool: notification.send
    params:
      # Extract nested JSON field
      email: "{{expr:jsonpath(user, '$.contact.email')}}"
      # Uppercase the name
      greeting: "{{expr:concat('Hello ', upper(jsonpath(user, '$.name')))}}"
      # Default if missing
      role: "{{expr:default(jsonpath(user, '$.role'), 'member')}}"

Date-based API calls

steps:
  - tool: analytics.query
    params:
      start_date: "{{expr:today('-7')}}"
      end_date: "{{expr:today()}}"
    store: metrics

  - tool: report.generate
    params:
      title: "{{expr:concat('Weekly Report: ', today('-7'), ' to ', today())}}"
      data: "{{metrics}}"

String manipulation

steps:
  - tool: git.log
    store: log_output

  - tool: slack.post
    params:
      # First 500 chars of output
      text: "{{expr:left(log_output, 500)}}"
      # Extract filename from path
      filename: "{{expr:cut('/home/user/docs/report.pdf', '/', '-1')}}"
      # Clean up whitespace
      summary: "{{expr:trim(log_output)}}"

Conditional with expressions

steps:
  - tool: api.health_check
    store: health

  - tool: pagerduty.alert
    # Only alert if status is not healthy
    if: "jsonpath(health, '$.status') != 'healthy'"
    params:
      severity: "critical"
      message: "{{expr:concat('Service down: ', jsonpath(health, '$.message'))}}"

Available functions

See the full expressions reference for all 20 functions: concat, cut, default, find, join, jsonpath, left, len, lower, now, replace, right, substr, today, trim, upper, and more.

How it works

  1. {{expr:...}} is a resolver backend — same system as {{vault:KEY}} and {{env:VAR}}
  2. In workflows, expressions have access to stored step outputs and input params
  3. In any tool call, stateless functions like now(), today(), upper() work
  4. Expressions that fail return empty string — no workflow crashes

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