Skip to main content
Glama
markomitranic

Data Visualization MCP Server

Server Quality Checklist

58%
Profile completionA complete profile improves this server's visibility in search results.
  • Latest release: v1.0.0

  • Disambiguation5/5

    The two tools have completely distinct purposes with no overlap. 'save_data' is for storing data in a table, while 'visualize_data' is for creating visualizations from saved data. The descriptions clearly differentiate their functions and usage contexts.

    Naming Consistency5/5

    Both tools follow a consistent verb_noun naming pattern ('save_data' and 'visualize_data'). The naming style is uniform throughout, using snake_case with clear action-object pairs that accurately reflect their functions.

    Tool Count2/5

    With only 2 tools, this server feels severely under-scoped for a data visualization domain. A complete visualization workflow would typically require tools for data manipulation, chart type selection, configuration adjustments, or exporting visualizations. The current set is too minimal for effective agent use.

    Completeness2/5

    The tool surface has significant gaps for a data visualization server. There are no tools for data transformation, filtering, or aggregation before visualization. Missing are tools for different visualization types, chart customization, or exporting results. The dependency on Vega-Lite specifications without helper tools creates a steep learning curve for agents.

  • Average 3.8/5 across 2 of 2 tools scored.

    See the Tool Scores section below for per-tool breakdowns.

    • No community issues in the last 6 months
    • 0 commits in the last 12 weeks
    • No stable releases found
    • No critical vulnerability alerts
    • No high-severity vulnerability alerts
    • No code scanning findings
    • CI status not available
  • Add a LICENSE file by following GitHub's guide. Once GitHub recognizes the license, the system will automatically detect it within a few hours.

    If the license does not appear after some time, you can manually trigger a new scan using the MCP server admin interface.

    MCP servers without a LICENSE cannot be installed.

  • This repository includes a README.md file.

  • No tool usage detected in the last 30 days. Usage tracking helps demonstrate server value.

    Tip: use the "Try in Browser" feature on the server page to seed initial usage.

  • Add a glama.json file to provide metadata about your server.

  • If you are the author, simply .

    If the server belongs to an organization, first add glama.json to the root of your repository:

    {
      "$schema": "https://glama.ai/mcp/schemas/server.json",
      "maintainers": [
        "your-github-username"
      ]
    }

    Then . Browse examples.

  • Add related servers to improve discoverability.

How to sync the server with GitHub?

Servers are automatically synced at least once per day, but you can also sync manually at any time to instantly update the server profile.

To manually sync the server, click the "Sync Server" button in the MCP server admin interface.

How is the quality score calculated?

The overall quality score combines two components: Tool Definition Quality (70%) and Server Coherence (30%).

Tool Definition Quality measures how well each tool describes itself to AI agents. Every tool is scored 1–5 across six dimensions: Purpose Clarity (25%), Usage Guidelines (20%), Behavioral Transparency (20%), Parameter Semantics (15%), Conciseness & Structure (10%), and Contextual Completeness (10%). The server-level definition quality score is calculated as 60% mean TDQS + 40% minimum TDQS, so a single poorly described tool pulls the score down.

Server Coherence evaluates how well the tools work together as a set, scoring four dimensions equally: Disambiguation (can agents tell tools apart?), Naming Consistency, Tool Count Appropriateness, and Completeness (are there gaps in the tool surface?).

Tiers are derived from the overall score: A (≥3.5), B (≥3.0), C (≥2.0), D (≥1.0), F (<1.0). B and above is considered passing.

Tool Scores

  • Behavior2/5

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

    No annotations are provided, so the description carries the full burden of behavioral disclosure. While it states the tool 'saves data' (implying a write operation), it lacks critical details: whether this requires specific permissions, if it overwrites existing tables, what happens on failure, or any rate limits. For a mutation tool with zero annotation coverage, this is a significant gap in transparency.

    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 appropriately sized and well-structured with clear sections ('When to use this tool' and 'How to use this tool'), making it easy to scan. Every sentence contributes to understanding the tool's purpose and usage, though it could be slightly more concise by integrating the sections more fluidly.

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

    Completeness3/5

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

    Given the tool has 2 parameters with full schema coverage and no output schema, the description adequately covers the basic purpose and usage. However, as a mutation tool with no annotations, it lacks details on behavioral aspects like error handling, permissions, or side effects, which are important for contextual completeness. This makes it minimally viable but with clear gaps.

    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 schema already documents both parameters ('name' and 'data') thoroughly. The description adds minimal value beyond the schema by restating parameter purposes in the 'How to use this tool' section. This meets the baseline of 3 when the schema does the heavy lifting, but doesn't provide additional semantic context.

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

    Purpose4/5

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

    The description clearly states the tool's purpose: 'save data to a named table for later use in visualizations.' It specifies the verb ('save'), resource ('data'), and intended use ('for later use in visualizations'), which is clear and actionable. However, it doesn't explicitly differentiate from its sibling 'visualize_data' beyond implying a sequential relationship.

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

    Usage Guidelines4/5

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

    The description includes a 'When to use this tool' section that provides clear context: 'Use this tool when you have data that you want to visualize later.' This gives explicit guidance on the tool's purpose. However, it doesn't specify when NOT to use it or mention alternatives (e.g., if there are other ways to store data), which prevents a perfect score.

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

  • Behavior4/5

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

    With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behavioral traits: it requires data to be saved first (a prerequisite), specifies that Vega-Lite v5 is used, and notes that the data field is automatically added (avoiding duplication). However, it lacks details on error handling, output format, or performance considerations, which would be helpful for a visualization tool.

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

    Conciseness5/5

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

    The description is well-structured and appropriately sized: it starts with a clear purpose statement, followed by bullet-pointed sections for usage guidelines and instructions. Each sentence adds value without redundancy, and the information is front-loaded for quick understanding. The format is efficient and easy to parse.

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

    Completeness4/5

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

    Given the tool's complexity (visualization with Vega-Lite), no annotations, and no output schema, the description does a good job of covering essential context: purpose, usage scenarios, prerequisites, and basic parameter semantics. However, it lacks details on what the visualization output looks like (e.g., image format, display method) and error cases, which would improve completeness for an agent invoking this tool.

    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?

    Schema description coverage is 100%, so the schema already documents both parameters thoroughly. The description adds minimal value beyond the schema: it mentions that data_name refers to 'the name of the table with the saved data' and vegalite_specification is 'a Vega-Lite specification,' but these are largely redundant with schema descriptions. No additional syntax, examples, or constraints are provided, meeting the baseline for high schema coverage.

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

    Purpose4/5

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

    The description clearly states the tool's purpose: 'produce a data visualization using the Vega-Lite grammar.' It specifies the verb ('produce') and resource ('data visualization'), but does not explicitly differentiate from its sibling tool 'save_data' beyond mentioning it as a prerequisite. The purpose is specific and actionable, though sibling differentiation is only implied through workflow dependency.

    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?

    The description provides explicit usage guidelines in a structured format: 'When to use this tool' lists scenarios (visual representation for complex/multi-dimensional data, not for singular data points) and 'How to use this tool' outlines prerequisites (save data first with save_data) and steps. It clearly distinguishes when to use this tool versus alternatives by stating it's not useful for singular data points and requires prior data saving.

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

GitHub Badge

Glama performs regular codebase and documentation scans to:

  • Confirm that the MCP server is working as expected.
  • Confirm that there are no obvious security issues.
  • Evaluate tool definition quality.

Our badge communicates server capabilities, safety, and installation instructions.

Card Badge

mcp-vegalite-server MCP server

Copy to your README.md:

Score Badge

mcp-vegalite-server MCP server

Copy to your README.md:

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/markomitranic/mcp-vegalite-server'

If you have feedback or need assistance with the MCP directory API, please join our Discord server