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mcp-nixos

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Python
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Server Quality Checklist

67%
Profile completionA complete profile improves this server's visibility in search results.

  • Latest release: v3.0.1

  • Disambiguation5/5

    Only two tools, and they have clearly distinct purposes: `nix` is the general-purpose query tool for all Nix-related lookups, while `nix_versions` is explicitly scoped to package version history. The description even directs users to `nix_versions` for history queries, eliminating any ambiguity.

    Naming Consistency4/5

    Both tool names share the 'nix' prefix, showing a loose consistency, but one uses a single word (`nix`) and the other uses an underscore compound (`nix_versions`). This is a minor deviation from a more uniform pattern, but not confusing.

    Tool Count3/5

    With only 2 tools, the count is on the low end, but the primary `nix` tool is a powerful monolith covering dozens of actions. It feels thin compared to typical servers, yet the consolidated design makes it functional. Borderline appropriate.

    Completeness4/5

    The `nix` tool covers a broad range of Nix domain operations: package and option search, channels, flakes, store paths, wiki, and nix.dev docs. `nix_versions` adds version history. Together they handle most query-centric needs, though mutations or builds are outside scope, leaving minor gaps.

  • Average 4/5 across 2 of 2 tools scored. Lowest: 2.9/5.

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

    • 18 of 19 community issues answered or closed in the last 6 months
    • 16 commits in the last 12 weeks
    • Last stable release on
    • No critical vulnerability alerts
    • No high-severity vulnerability alerts
    • No code scanning findings
    • CI is failing

  • This repository is licensed under MIT License.

  • 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.

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

    Then . Browse examples.

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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?

    With no annotations provided, the description should disclose behavioral traits. It only states it retrieves version history, but offers no details about pagination, error handling, rate limits, or what constitutes a valid response.

    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?

    Single sentence, no fluff. It is concise but could be slightly expanded without losing efficiency.

    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?

    An output schema exists, so return value documentation is not required. However, given three parameters and no annotations, the description is minimal and leaves gaps in understanding the tool's full behavior.

    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 coverage is 100%, and the descriptions for parameters ('Package name', 'Specific version to find', '1-50') are clear. However, the tool description adds no extra value beyond the schema itself.

    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 action (Get) and resource (package version history from NixHub.io). It conveys the purpose effectively but does not differentiate from the sibling tool 'nix'.

    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?

    No guidance on when to use this tool versus alternatives. The description lacks context about prerequisites, limitations, or comparison to the sibling tool 'nix'.

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

  • Behavior5/5

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

    With no annotations provided, the description carries the full burden and excels. It discloses nuanced behaviors: how `browse` only works with certain sources, the exact matching semantics for `action=info` (attribute path first, then pname, with disambiguation flags), normalization for NVF paths, accepted URL forms for nix-dev, and the policy to omit parameters rather than pass empty strings. This is exceptionally transparent.

    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 long but every section earns its place: a concise summary, clear usage guidance, a structured INTENTS → CALLS table, and focused notes that resolve common pitfalls. It is well front-loaded with the core purpose, and the format makes the dense information scannable. Nothing feels redundant or wasteful.

    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 (8 parameters, multiple sources, multiple actions) and zero annotations, the description is remarkably complete. It covers purpose, usage context, behavioral details, parameter semantics, and even differentiates from the sibling tool. The presence of an output schema means the description need not explain return structures, and it doesn't, staying appropriately scoped.

    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?

    Although the schema already provides 100% parameter descriptions, the description goes far beyond by mapping natural-language intents to exact JSON shapes (e.g., 'is package X in channel Y?' -> {"action": "info", "query": "X", "channel": "Y"}). It also clarifies valid combinations, defaults, and special behaviors (e.g., 'source' can be a path for flake-inputs, 'limit' ranges differ per action). This adds substantial semantic value over the bare schema.

    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 opens with a clear verb ('Query') and enumerates the full set of resources (NixOS, Home Manager, Darwin, FlakeHub, flakes, Nixvim, NVF, Wiki, nix.dev, Noogle, NixHub). It also distinguishes itself from the sibling tool `nix_versions` by explicitly routing package version history queries there, making the purpose unambiguous and well-differentiated.

    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 when-to-use guidance ('Use this tool for anything touching nixpkgs... even when you think you know the answer') and explicitly names alternatives to prefer over ('Prefer this over `nix search`, scraping search.nixos.org, or running `gh api`'). It also gives a clear exclusion: package version history should go to `nix_versions`. This is textbook usage guidance.

    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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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.

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