Skip to content

Voice Agent Linter

by modernmustardseed.com · remote · no sign-in to list tools · v1.0.0 · published by com.modernmustardseed

Lints a phone voice agent prompt and platform config before real callers reach it.

Changes · 1
CompareRegistry entry

3 tools: 1 change things and 2 only read.

Scanned Oct 21, 2026

1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http voice-linter https://mcp.modernmustardseed.com/voice-linter

Findings

Matches of fixed checks, with the text they matched.

1 info

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

3 tools

Changes things 1Claude Code: ask
  • lint_voice_agentCheck a phone voice agent’s system prompt and, optionally, its config JSON (Vapi assistant, Retell agent or LLM, ElevenLabs agent, or OpenAI Realtime session) against rule-based ch…1 finding

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Info

      The description mentions "credentials".

      Matched text

      description: "...o 100 score and a verdict. Do not paste credentials: API keys, bearer tokens, passwords and..."

      What this check looks for
    Description, as the server wrote it
    Check a phone voice agent’s system prompt and, optionally, its config JSON (Vapi assistant, Retell agent or LLM, ElevenLabs agent, or OpenAI Realtime session) against rule-based checks learned on live calls. Finds: no live date and dates without a year; phone numbers, emails, URLs, hyphen ranges and long numbers the voice will misread; no spelling protocol or bare-letter spelling; instructions to pass as human, missing AI disclosure and missing recording notice; scripted tool start lines, stall phrases and silent or long openers; tools with no description, untyped or undescribed parameters, undefined required fields, unformatted date parameters and unstated results; Vapi nested item enums, flat analysisPlan keys, disabled plans and plans without the transcript; ElevenLabs Turbo stutter risk; no transfer or callback path and no end-call; placeholders, secrets, very long prompts and contradictory always and never rules. Each finding has a rule id, severity, the exact line (and JSON path for config), an excerpt, a specific message and the fix; disclosure and recording rules carry their legal citations with the date read. Returns a 0 to 100 score and a verdict. Do not paste credentials: API keys, bearer tokens, passwords and the values of secret-named config fields (apiKey, secret, token, password, credentials, Authorization) are stripped from the input before any check runs and replaced with "[secret removed]", so they are never read, returned, logged or stored; the output says how many were removed. No model reads the input and nothing is stored. Informational, not legal advice.

    Annotations the server declares

    • title: Lint a voice agent
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
Only reads 2Claude Code: allow
  • explain_lint_ruleExplain one Voice Agent Linter rule by id: why it exists, a bad and a good example, the fix, the platforms it applies to, and its sources with the date each was read.No findings

    Why it is in this group

    • The name "explain_lint_rule" says "explain": a word for reading.
    Description, as the server wrote it
    Explain one Voice Agent Linter rule by id: why it exists, a bad and a good example, the fix, the platforms it applies to, and its sources with the date each was read. Static reference, no network access.

    Annotations the server declares

    • title: Explain a lint rule
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • list_lint_rulesList every Voice Agent Linter rule with its id, title, default severity, category, what it reads (prompt, config or both) and the platforms it applies to.No findings

    Why it is in this group

    • The name "list_lint_rules" says "list": a word for reading.
    Description, as the server wrote it
    List every Voice Agent Linter rule with its id, title, default severity, category, what it reads (prompt, config or both) and the platforms it applies to. Filter by platform or category. Static reference, no network access.

    Annotations the server declares

    • title: List lint rules
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 1.0.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http voice-linter https://mcp.modernmustardseed.com/voice-linter

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__voice-linter__list_lint_rules",
      "mcp__voice-linter__explain_lint_rule"
    ],
    "ask": [
      "mcp__voice-linter__lint_voice_agent"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as voice-linter. Review it before you use it.