Basis

drawing_add

Draw on the chart. Points are {time, price} in chart coordinates — time in seconds, matching the candle timestamps a data handle reports. A horizontal line needs one point; a trendline or box needs two. Both numbers must be copied from a tool result — a summary's max with its maxAt, a crossing with its time — never read off your own prose or carried over from a different computation. The result echoes back what was drawn: check it against the figures you are about to quote, because a line that disagrees with the paragraph beside it is worse than no line. Changes the chart you are building; call chart_link when you are done so the person can open it.

Input Schema

TableJSON Schema

Name	Required	Description
`ref`	No	A handle from market_candles. Given one, the points are checked against the window it covers and a drawing that would land outside it is refused. Pass it whenever the coordinates came from a computation.
`fill`	No	Palette fill colour, or “none”.
`text`	No	Text for annotation tools.
`tool`	Yes	A tool id from catalog_search with kind "drawing" — e.g. horizontalLine, trendLine, rectangle, fibRetracement, longPosition or shortPosition. Prefer position_draw_on_chart for an entry/stop/target box. Separators and capitalisation are forgiven; an id that names no tool is refused.
`color`	No	A palette name. “up” and “down” are the reserved green and red — they assert a bullish or bearish claim, so use them for position zones and not for a measurement.
`width`	No	Stroke width in pixels, 1 to 6.
`levels`	No	Custom Fibonacci ratios. Example: [0, 0.382, 0.5, 0.618, 0.786, 1, 1.272, 1.618].
`points`	Yes
`symbol`	No	Defaults to the charted symbol.
`opacity`	No	Strength of the whole drawing, 0.1 to 1. Fade a level that is context rather than the decision.
`arrowEnd`	No
`fontSize`	No	Label/text size from 8 to 28.
`lineStyle`	No
`showStats`	No
`arrowStart`	No
`extendLeft`	No
`showLabels`	No
`extendRight`	No
`fillOpacity`	No	Shape fill opacity from 0 to 1.

Schema Changelog

Changes observed during successful MCP inspections.

First observedSep 20, 2026

TDQS

A4.9/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations are all false (readOnly, destructive, idempotent, openWorld), so the description carries the full burden. It discloses that the tool 'Changes the chart you are building', explains validation behavior (refused if outside window when ref given), and describes the response echo ('echoes back what was drawn') – all beyond the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is ~150 words and front-loaded with the core purpose and coordinate rule. Every sentence adds value, though a few details (e.g., 'The result echoes back...') could be tightened without losing information. Still, it's appropriately sized for a 19-parameter tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (19 params, no output schema, 58% schema coverage), the description covers essential context: coordinate semantics, point counts, validation with ref, sibling routing, and the final chart_link step. Nothing an agent needs to invoke it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 58%, so the description adds substantial meaning. It explains the points format (time in seconds matching candle timestamps, one point for horizontal line, two for trendline/box), the tool parameter format, the reserved meaning of 'up'/'down' colors, and when to pass the ref handle. This complements the schema effectively.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Draw') and resource ('the chart'), and immediately clarifies coordinate format. It distinguishes from position_draw_on_chart by name and explains when to prefer that sibling, so an agent can tell them apart.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit when-to-use guidance: 'Prefer position_draw_on_chart for an entry/stop/target box' and instructs to 'call chart_link when you are done'. It also warns against using stale or self-generated coordinates, providing clear boundaries for correct usage.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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