chart-annotation

Chart Annotation Skill

When to use

You want to call out a technical level, a pattern, or an event on a stock's price chart. Drawing directly on the chart is almost always clearer than describing it in prose. Reach for draw_chart_annotation whenever you would otherwise say "look at the level around 205" or "notice the downtrend from October to December".

MarketView is the app's live, trading-chart style price chart page (pan, zoom, switch timeframes). You do not need the user to be on it to annotate. If they are, the drawing appears on their live chart immediately. Anywhere else in the app, the same drawing renders as a chart card in the chat that opens the live chart beside the conversation, so annotate freely whenever it helps, then mention the user can click the card to see it.

Both tools are always available; this guide is how to use them well:

• draw_chart_annotation — add a single annotation to a chart.
• manage_chart_annotations — list, remove, or clear annotations.

Interactive chart vs. a Python chart (deliverable)

There are two ways to show price information visually — pick by what the user needs:

• The annotation tools (interactive). Annotations land on a live, pannable chart: MarketView's, or the one a chart card in the chat opens. Best when the user just wants to see and explore a level, pattern, or event themselves — quick, in-the-moment, nothing to hand off.
• A Python chart (deliverable). A static image you render with code and embed in a report or document. Best when the output is a deliverable the user keeps, shares, or exports — a research note, PDF, or deck.

The two aren't exclusive: draw on the live chart for a quick look, render a Python chart when it belongs in a written artifact, or do both.

Charts are identified by SYMBOL:timeframe

Every annotation belongs to a chart identified by its ticker + timeframe (e.g. NVDA:1day) — that pair is the chart's id:

• Pass the same symbol + timeframe again to add to / edit that same chart (annotations accumulate on it).
• Use a different ticker or timeframe to start a separate chart — so you can draw several charts in one turn (e.g. AAPL:1day and AAPL:1hour, or AAPL:1day and MSFT:1day), each rendered as its own card.

Always pass the ticker the user is discussing. timeframe defaults to 1day; set it to match the interval the user is viewing (one of 1min, 5min, 15min, 30min, 1hour, 4hour, 1day). Annotations are scoped to that one chart instance — a line drawn on NVDA:1day does not appear on NVDA:1hour.

Time format (any annotation with a time field). Pass ISO 8601 datetimes (e.g. 2024-11-14T00:00:00Z) aligned to a bar on the chart — for daily bars, midnight UTC of that day is safest. A time that doesn't land on a bar still renders but may look offset. Applies to trendline, marker, vertical_line, text, event, and fib_retracement.

Reacting to a user's chart selection

A <chart-selection> block in the user's turn means they selected something on the chart and sent it to you. Its selection_type is one of:

• region — a time×price box. Bounds come as a time range + price range, with the OHLCV bars inside it.
• price_level — a single horizontal price they tapped.

The user may send several blocks in one turn — treat each independently. A block may carry a User note: line: that is the user's own comment about that selection (separate from their message text) — let it steer what you look for there.

Analyze each bounded area (lean on the supplied bars and/or your market-data path), then, when it helps, draw your read back onto the same symbol + timeframe with draw_chart_annotation — a rectangle over a region, or a price_line at a price_level. Each block already spells out the matching draw_chart_annotation(...) call; adjust it to the level or zone your analysis actually lands on.

---

Picking the right variant

draw_chart_annotation takes an annotation object discriminated by its type field.

price_line — horizontal level

Use for anything flat on the y-axis: support, resistance, a target, a stop, an analyst price target, a 52-week high.

{
  "type": "price_line",
  "price": 205.0,
  "label": "Resistance 205",
  "style": "dashed"
}

trendline — two anchor points

Use to connect two (time, price) points on the chart: channel tops, pattern boundaries, connecting highs/lows across dates.

{
  "type": "trendline",
  "point1": {"time": "2024-10-16T00:00:00Z", "price": 145.2},
  "point2": {"time": "2024-12-20T00:00:00Z", "price": 138.7},
  "label": "Descending trend"
}

marker — single-bar event

Use for a callout at one specific date: earnings beat, entry signal, news event, grade change.

{
  "type": "marker",
  "time": "2024-11-14T00:00:00Z",
  "shape": "arrowUp",
  "position": "belowBar",
  "text": "Earnings beat"
}

shape options: arrowUp, arrowDown, circle, square. position options: aboveBar, belowBar, inBar.

vertical_line — a moment in time

Use to mark a single date across the whole chart: an earnings date, a split, an FOMC meeting, the start of a move.

{
  "type": "vertical_line",
  "time": "2024-11-14T00:00:00Z",
  "label": "Earnings",
  "style": "dashed"
}

rectangle — a zone

Use for supply/demand zones, consolidation ranges, or any box over a region of the chart. point1 and point2 are two opposite corners (the fill is translucent so candles stay visible).

{
  "type": "rectangle",
  "point1": {"time": "2024-10-16T00:00:00Z", "price": 150.0},
  "point2": {"time": "2024-11-20T00:00:00Z", "price": 140.0},
  "label": "Demand zone"
}

text — a free-floating label

Use for a callout that isn't tied to a marker or level. Anchored at a (time, price) point.

{
  "type": "text",
  "time": "2024-11-14T00:00:00Z",
  "price": 205.0,
  "text": "Breakout"
}

event — news/event badge with detail

Use when a callout needs more than a one-line label: an earnings report, an acquisition, an analyst upgrade, a product launch. Anchored at a (time, price) point, it shows a short title badge on the chart; the detail (a few sentences) is revealed on hover (desktop) or tap (mobile). Prefer this over marker/text when you want to explain why the event matters.

{
  "type": "event",
  "time": "2024-11-14T00:00:00Z",
  "price": 205.0,
  "title": "Q3 earnings beat",
  "detail": "Reported EPS of $1.40 vs $1.25 consensus and raised full-year guidance ~5%. Shares gapped up the next session on the print and the brighter outlook."
}

fib_retracement — Fibonacci levels

Use to map retracement targets of a move. Pass the two ends of the swing (e.g. swing low → swing high); standard levels (0, 0.236, 0.382, 0.5, 0.618, 0.786, 1.0) are drawn between them automatically.

{
  "type": "fib_retracement",
  "point1": {"time": "2024-10-16T00:00:00Z", "price": 100.0},
  "point2": {"time": "2024-12-20T00:00:00Z", "price": 200.0},
  "label": "Oct–Dec move"
}

---

Managing annotations

manage_chart_annotations covers list / remove / clear_all:

# See what's there
manage_chart_annotations(symbol="NVDA", action="list")

# Remove specific ones (get ids from `list`)
manage_chart_annotations(symbol="NVDA", action="remove", ids=["ann_ab12..."])

# Wipe everything for the symbol
manage_chart_annotations(symbol="NVDA", action="clear_all")

• remove requires a non-empty ids list. The tool will reject an empty call.
• clear_all must not be given ids. Use remove for partial deletion.
• Existing chart primitives the user set up themselves (52W high, analyst target lines, earnings markers) are not managed by these tools and are never touched by clear_all.

---

Tips

• Short labels. Chart space is tight — aim for a few words ("Resistance 205", "Entry", not "Strong resistance level we should watch"). Put the reasoning in the chat message, not the label.
• One annotation per tool call. If you want three levels, call draw_chart_annotation three times.
• Clean up stale work. If you drew provisional levels and the conversation moved on, offer to clear_all before drawing a fresh set.
• No need to flag your drawings. Agent-drawn items render with a subtle dashed style, so the user can already tell them apart from their own — you don't have to call out which annotations you added.