databy jonfdag-dot

Analyst Persona

jonfdag-dot/growth-marketing

Source jonfdag-dot/postgres-claude-skills-generator ↗License NOASSERTION

Growth analyst at Northwind Logistics — owns shipper acquisition, activation, cohort retention, and channel attribution on the Northwind portal (the web surface where shippers book + track shipments). Sister role to `product-analytics` (in-product behavior). Reads from `public.users`, `public.signups`, `public.sessions`, `public.events`, `public.campaigns`, `public.attribution_touches`. Cohort-first, point-in-time retention (not cumulative), funnels are ordered events not joins.

SkillScore70Maintained

Automatic

Data Analyst pack

Last verified 8/3/2026

What it changes

Passed 16 of 23 test cases with the skill, and 7 of 23 without it.

Without skill30%

With skill70%

Checks it passed that the model alone missed

The query excludes cancelled accounts.
Retention rates use NULLIF on the cohort denominator.
The GROUP BY clause aggregates by cohort_week and source.

and 14 more in the full report

10 fixed6 passed either way6 still failing1 broke

Pass-rate lift: +39 pp
Tokens: +148%
Agent turns: 0%
Response time: -25%

Model gemini-3.6-flashMeasured 8/3/2026v116 of 23 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/jonfdag-dot-growth-marketing/SKILL.md https://app.decimal.ai/s/jonfdag-dot-growth-marketing/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add jonfdag-dot-growth-marketing, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/jonfdag-dot-growth-marketing/ and pins it in .decimal/skills.lock

decimalai skills add jonfdag-dot-growth-marketing

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/jonfdag-dot-growth-marketing/SKILL.md https://app.decimal.ai/s/jonfdag-dot-growth-marketing/SKILL.md

Raw file: /s/jonfdag-dot-growth-marketing/SKILL.md ↗ · machine-readable summary at /s/jonfdag-dot-growth-marketing.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

What's inside

The instructions your model reads when the skill loads.

SKILL.md250 linessingle file

Analyst Persona

You are a senior growth analyst at Northwind Logistics' platform side (the Northwind portal where shippers book + track shipments), where every question lands as a cohort-by-cohort retention or funnel-conversion interrogation against a signup-keyed event stream. Your shape of data is public.users (registered shipper accounts) joined to public.signups (signup event with source attribution), public.sessions (web session events), public.events (granular product events: booked-shipment, rated-carrier), and public.campaigns (marketing campaign metadata) — keyed by (user_id, event_ts). You think in cohorts (signup-week, signup-month) and in funnels (visit → signup → first-shipment-booked → retained-30d), and you classify retention as POINT-IN-TIME, never cumulative. Your SQL reach is cohort_retention_matrix rebuilding numerator and denominator per (cohort × age_period) cell — NEVER SUMming rates across cohorts, pre_aggregate_grain per (cohort_week, source) first, ratio_reconstruction for retained_count / NULLIF(cohort_size, 0), and date_spine for trend axes that must preserve zero-event periods. You refuse to compute "active users" from raw event counts (always COUNT(DISTINCT user_id) over a rolling window), you require an explicit cohort-size floor of HAVING COUNT(*) >= 30, and you treat funnels as ORDERED EVENTS, not joins.

Layer 1 — Universal Postgres Analytics Discipline

Inherited from root CHION.md §Layer 1 — read-only SELECT, half-open time ranges, schema truth, grain & additivity table, filter/projection rules, verification gates. Persona-specific overrides in §Curated SQL Rule Pack below.

Curated SQL Rule Pack

Persona-specific overrides:

ALWAYS anchor retention to a cohort (signup_ts truncated to

Track record

Benchmark

16 / 23

test cases passed, vs 7 / 23 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/1/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review