artscii

chart

Generate ASCII art charts from data: progress bars, sparkline trends, and 2D heatmaps. Display statistics directly in terminal or chat.

Instructions

Render data as ASCII charts. Types: progress (bar), sparkline (trend), heatmap (2D grid).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "type": "<type>"
    },
    "name": "chart"
  }
}

Input Schema

Name	Required	Description	Default
`type`	Yes	Chart type
`percent`	No	Progress: completion % (0-100)
`items`	No	Progress: multiple labeled bars
`values`	No	Sparkline: numeric values to chart
`data`	No	Heatmap: 2D array of numeric values
`rowLabels`	No	Heatmap: row labels
`colLabels`	No	Heatmap: column labels
`width`	No	Width in characters
`style`	No	Visual style (varies by type)	default
`label`	No	Progress: label for single bar

Schema Changelog

Changes observed during successful MCP inspections.

AddedMay 6, 2026

TDQS

B3.1/5.0

Behavior2/5

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states 'Render data as ASCII charts' and lists types, but fails to explain output format, side effects, resource usage, or limitations. This is insufficient for an agent to understand the tool's behavior.

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 a single sentence that front-loads the main purpose and lists types. It is concise and avoids verbosity. However, it could benefit from a slightly more structured format to enhance readability, but overall it is efficient.

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

Completeness2/5

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

Given the complexity of 10 parameters and no output schema, the description is incomplete. It does not explain how parameters relate to each chart type (e.g., percent vs items for progress), nor does it describe the output format or return value. This leaves gaps for effective use.

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

Parameters3/5

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

The schema description coverage is 100%, so the meaning of each parameter is already clear from the schema. The description adds contextual grouping (e.g., progress=bar, sparkline=trend, heatmap=2D grid) which helps, but does not add significant new semantic value beyond what the schema provides.

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?

The description clearly states the tool renders data as ASCII charts and lists the supported types (progress, sparkline, heatmap). The verb 'Render' and resource 'data as ASCII charts' are specific, and the tool is easily distinguished from sibling tools like animate or diagram.

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

Usage Guidelines2/5

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

The description provides no guidance on when to use this tool versus alternatives among siblings. It does not mention when-not to use it or suggest alternative tools for related tasks, leaving the agent with no context for selection.

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

Deploy Server