| name | composing-emails |
| description | General styling and tone guidelines for composing HTML emails. Use when writing email copy that will be rendered as HTML — covers the paragraph/heading/link block model, tone, subject lines, and how to handle data, URLs, and emphasis without markdown. |
Composing emails
The block model
Emit content as an array of { tag, content } blocks. Only three tags exist:
- paragraph →
<p> body copy
- heading →
<h2> section header
- link →
<a> for URLs
No lists, tables, images, bold/italic, blockquotes, or code blocks. If you need emphasis, use a heading + paragraph. If you need a list, write each item as its own paragraph. All strings are HTML-escaped, so don't try to inject tags.
Formatting rules
- No markdown. No
# headings, no **bold**, no - bullets — they render literally.
- No newlines inside a block's
content — break into separate blocks instead.
- Preserve URLs from source data as
link blocks, not inline in paragraph text.
- Format numbers, prices, and dates clearly inside paragraph copy (e.g.
$1,234.56, April 28, 2026).
Tone
- Professional but friendly
- Descriptive subject line — not "Update" or "FYI"
- Lead with the point; don't bury it under context
- One idea per paragraph
Recipient sourcing
Always read the recipient address from a typed signal-payload field interpolated into the action prompt — never from upstream agent output. LLM agents will confabulate plausible-looking addresses when the field is absent rather than failing.
Wire it end-to-end:
-
Signal schema declares the recipient as a required field — caller can't trigger the job without it.
signals:
send-alert:
schema:
type: object
properties:
notify_email: { type: string, format: email }
required: [notify_email]
-
Action prompt interpolates from the signal payload (works in any step, including ones with inputFrom — see writing-workspace-jobs → "Signal payload threading"):
- type: agent
agentId: emailer
prompt: "Send the alert to {{inputs.notify_email}}"
-
Email-sender agent system prompt should refuse rather than guess: "If the recipient address contains an unresolved {{...}} placeholder or is missing, call failStep with a reason. Never invent a recipient."
The literal-placeholder check is the important part — the FSM engine intentionally leaves unresolved placeholders verbatim so authoring bugs stay visible. A guarded agent treats that as a hard stop.
