Email Classifier Skill | Agent Skills

Email Classifier

Dependency: This skill produces LLM-facing classification output. Load /mnt/skills/user/prompt-engineering/SKILL.md and apply all rules before writing any prompt, instruction, or directive below.

Taxonomy reference: Load references/taxonomy.md before classifying any email. All domain, descriptor, and type registries, locale rules, and worked examples live there. MUST NOT classify from memory alone.

Task

Assign the minimum accurate set of tags from the closed taxonomy to classify the provided email. Output a single comma-separated tag string.

Input

Email data is provided at runtime wrapped in XML:

<email>
  <subject>{{SUBJECT}}</subject>
  <sender>{{SENDER}}</sender>
  <body>{{BODY}}</body>
</email>

{{BODY}} MAY be omitted; classify from {{SUBJECT}} and {{SENDER}} alone if so
{{SENDER}} includes display name and/or email address — both are useful signals

Constraints

MUST load references/taxonomy.md before every classification run; MUST NOT rely on memorised tag lists
MUST assign at least one domain tag per email; MUST NOT emit type or descriptor tags without a domain tag
MUST only use tags from the closed registries in references/taxonomy.md; MUST NOT synthesise, extrapolate, or invent tags — use the nearest standalone domain tag instead
MUST NOT use American terminology; use British English throughout as defined in Section 1.2 of the taxonomy
SHOULD assign the minimum number of tags that accurately describe the email; MUST NOT pad classifications with speculative or loosely applicable tags
IF no type tag precisely matches THEN omit it; MUST NOT approximate with a near-miss type tag

Process

flowchart TD
    A[Receive email] --> B[Load references/taxonomy.md]
    B --> C[Identify domain tags\nWhat is this email about?]
    C --> D{Spans multiple\nsubject areas?}
    D -->|Yes| E[Assign all applicable\ndomain tags]
    D -->|No| F[Assign one\ndomain tag]
    E & F --> G[Identify descriptor tags\nDoes the domain need narrowing?]
    G --> H{Descriptor adds\ndiscriminating value?}
    H -->|Yes| I[Assign descriptor\nfrom taxonomy]
    H -->|No| J[Omit descriptor]
    I & J --> K[Identify type tags\nWhat kind of email is this?]
    K --> L{Precise type tag\nexists in taxonomy?}
    L -->|Yes| M[Assign type tag]
    L -->|No| N[Omit type tag]
    M & N --> O[Apply lifecycle\nrouting rules below]
    O --> P[Output tag string]

Lifecycle Routing

Apply AFTER assigning classification tags, BEFORE outputting:

IF tags include ANY OF [invoice, appointment, contract, mot, prescription]
THEN append status/todo

IF tags include ANY OF [alert, fine]
THEN append priority/urgent

Output Format

A single line of comma-separated lowercase tags:

domain[, domain...][, descriptor...][, type...][, status/todo][, priority/urgent]

IF classification is uncertain THEN append a warning on the next line:

⚠ <reason for uncertainty> — verify manually

MUST NOT output explanatory prose alongside the tag string unless explicitly asked.

Examples

| Email | Output | |---|---| | Tradesperson quote for boiler replacement | property, utilities, gas, quotation | | Admiral car insurance renewal | automotive, insurance, renewal, status/todo | | Pet insurance claim and invoice | pet, insurance, claim, invoice, status/todo | | MOT certificate from garage | automotive, mot, certificate, status/todo | | HMRC self-assessment reminder | finance, government, tax, reminder, status/todo | | New Claude model release announcement | ai, llm, model, release | | GitHub Actions pipeline failure | engineering, pipeline, alert, priority/urgent | | New device sign-in notification | security, signin, alert, priority/urgent | | Speeding penalty charge notice | automotive, government, fine, invoice, priority/urgent | | Node.js end of life notice | engineering, tech, eol | | Weekly TLDR tech newsletter | tech, newsletter | | Home Assistant beta release notes | smarthome, tech, beta, changelog |

Edge Cases

| Scenario | Rule | |---|---| | Email spans home and car insurance renewal | Assign both property and automotive | | Invoice with no identifiable domain | Fall back to finance, invoice | | Tech newsletter referencing AI models | tech, newsletter — MUST NOT apply ai unless the email is specifically about an AI model, platform, or framework rather than tech news generally | | AI model release affecting your own stack | ai, engineering, platform, deprecation — apply engineering only when your own code or infrastructure is directly impacted | | MFA code email | security, mfa — MUST NOT append priority/urgent; MFA codes are transient and expected, not security incidents | | Body unavailable, subject ambiguous | Classify from sender domain and subject only; append ⚠ warning if genuinely uncertain | | Combined home and contents insurance | property, insurance, renewal — single domain, no need for automotive unless vehicle cover is bundled |

Agent Skills: Email Classifier

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