Category Monitor

Category Monitor

This skill tracks one Mercado Livre (Brasil) category's aggregate health over time — its estimated sales, number of products and catalog products, number of active sellers, the distribution of sellers across medal tiers, and how concentrated the market is (monopolization).

Each run builds today's snapshot table for the category and offers it as a downloadable table. To see what changed, the user supplies the table from a previous period (the one this skill produced before); the skill compares the two and shows the difference per metric. The baseline is whatever table the user provides — there is no hidden session memory and nothing is stored server-side. The default view is the whole category; the user may instead point it at a single listing or a catalog product (a catalog product rolls up its competing listings).

To track one named product over time, use the product-change-monitor skill. For a one-shot opportunity / market-size snapshot, use the category-opportunity-index skill.

Prerequisites

• JoomPulse MCP access is configured for the current agent environment.
• The user names a category (or, optionally, a single listing or catalog product).
• For a period comparison, the user supplies a previous table that this skill produced for the same

category (pasted or uploaded). Without it, the skill produces a standalone snapshot.

• The available JoomPulse tools can return a category's aggregate metrics and its seller-medal

distribution.

If JoomPulse MCP access is unavailable, stop and explain that the skill requires JoomPulse MCP setup before it can monitor a category.

Scope

• Mercado Livre (Brasil) only. Other marketplaces are out of scope.
• Sales and revenue are JoomPulse estimates derived from historical listing data — not real

transactions. Disclose this in every output.

• Read-only. The skill never writes or modifies anything; it does not store the snapshot — the

user keeps the downloadable table and brings it back next period.

• Language: detect the seller's language and respond in it. Default to pt-BR.
• The baseline is user-supplied. Never claim a change without a previous table to compare against,

and never infer or fabricate one from memory.

Workflow

Step 1 — Resolve what to monitor

Ask for a category if none was given, then use JoomPulse to match the free text to a category (disambiguate with the user when several plausible matches return). Optionally, the user can point the skill at a single listing or a catalog product instead.

Step 2 — Collect today's aggregates

Use JoomPulse to collect, for the target: estimated sales, number of products, number of catalog products, number of active sellers, the seller-medal distribution, and the monopolization level.

Step 3 — Present today's snapshot and offer it for download

Render the snapshot table for today (head it with the category name and the date). This table is the deliverable — and offer it as a downloadable file (.csv / .xlsx) so the user can save it and bring it back next period as the baseline. On a standalone snapshot there is no change column and no color-dot legend — just metric and current value.

Step 4 — Offer comparison, and compare if a previous table is supplied

Invite the user to send a previous table for the same category to compare periods. If they provide one, parse its metric values, align by metric to today's snapshot, and render a comparison table with the difference per metric. A difference requires both an old and a new value for the same metric — if a metric is missing or unreadable in the supplied table, show —, never a fabricated trend. If no previous table is supplied, the snapshot stands on its own and the user is told to save it for next time.

Output

Respond in the seller's language (default pt-BR).

Snapshot (always): a markdown table | Métrica | Valor atual | for Vendas (estimadas), Produtos, Produtos de catálogo, Vendedores, Distribuição de medalhas, Monopolização, plus a downloadable .csv / .xlsx of the same data.

Comparison (only when a previous table is supplied): a markdown table | Métrica | Anterior | Atual |. Put the change (figure or percentage point) inside the Atual cell, prefixed with a semantic color dot:

• Vendas ↑ = 🟢; Vendas ↓ = 🔴.
• Monopolização is inverted (like cancellation rate): down = 🟢 (easier to enter), up = 🔴.
• Produtos / Vendedores moving is neutral context — show the change without a strong good/bad dot.
• Distribuição de medalhas — show the tiers that moved (for example platina 4 → 5).

Column headers are words (Métrica | Anterior | Atual), never a bare "Δ" symbol. Show the color-dot legend (🟢/🔴) only in the comparison table, where the dots actually appear — never on a plain snapshot.

Close with a short Principais insights section: with a comparison, interpret what moved; on a standalone snapshot, frame it as the starting picture with no trend claims.

Disclaimer (every report):

> ⚠️ Vendas, vendedores, produtos e monopolização são estimativas do JoomPulse com base no histórico > de anúncios — não são transações reais. / Sales, sellers, products, and monopolization are JoomPulse > estimates based on historical listing data — not actual transactions.

Visualization

When the client can render inline visuals, present metric cards and a medal-distribution chart; otherwise fall back to the markdown tables plus text cards. Never block on visuals. The snapshot table (and the comparison table, when present) always render as markdown in the response text, and the downloadable file mirrors what is shown.

When inline visuals are available:

• Cards: estimated sales, number of products, number of catalog products, and number of active

sellers — plus the monopolization level as a value or small bar. With a comparison, you may annotate each card with its anterior → atual change.

• A medal-distribution bar: sellers (or listings) split across medal tiers, using the medal

palette — platina = purple, ouro = amber, prata = blue, sem medalha = white with a thin border (white needs the border to stay visible on a light background). With a previous table, note the shift.

• No synthesized trend line from a single run (there is no server-side history). Only if the user

supplies several past-period tables may you plot a simple line across those periods.

Presentation rules: column headers are words, never a bare "Δ" symbol; show the color-dot legend only when those dots appear (the comparison table); render a chart only when the data supports it.

Notes & Guardrails

The seller should never see a system or stack error — only a friendly next step.

• No previous table supplied: render today's snapshot only (no change column, no legend) and

invite the user to save it for next time.

• Supplied table is for a different category, malformed, or unreadable: say so plainly and fall

back to the snapshot only; do not force a misaligned comparison.

• Empty or failed data: say the data is temporarily unavailable and to try again. Never paste

internal error text, HTTP codes, or field names to the seller.

• Catalog product input: when monitoring a catalog product, note the buy-box competition (how many

sellers compete) rather than implying a single listing.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: joomcode
• Source: joomcode/joompulse-skills
• License: MIT
• Homepage: https://joompulse.com/mcp-connector

Install and usage instructions live in the source repository linked above.