grok-build-mcp

grok_challenge

Adversarially break code to uncover edge cases, race conditions, and security vulnerabilities. Returns severity-ranked issues with reproductions.

Instructions

Ask Grok to adversarially break a piece of code: edge cases, race conditions, security holes, adversarial inputs. Returns severity-ranked issues with reproductions.

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": {
      "code": "<code>"
    },
    "name": "grok_challenge"
  }
}

Input Schema

Name	Required	Description
`code`	Yes	The code or design to attack.
`context`	No	Optional context: language, framework, intended behaviour, constraints.
`model`	No
`timeout`	No	Per-call timeout in seconds. Defaults to 300. Raise for long grok-4 reasoning.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.2.0Jun 12, 2026

addedInput schema / properties / timeout

Added value: +{
+  "description": "Per-call timeout in seconds. Defaults to 300. Raise for long grok-4 reasoning.",
+  "exclusiveMinimum": true,
+  "minimum": 0,
+  "type": "number"
+}

First observedv0.1.0May 26, 2026

TDQS

A3.5/5.0

Behavior3/5

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

With no annotations, the description bears full responsibility. It states the tool returns severity-ranked issues with reproductions, offering reasonable output transparency. However, it does not disclose side effects, mutation risks, or any operational constraints beyond what the parameters imply.

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 a single sentence with a colon, efficiently conveying purpose and output. Every word is meaningful, with no extraneous content.

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 absence of an output schema and the four-parameter signature, the description provides a reasonable overview of inputs and outputs. However, it lacks details on return format, pagination (if any), and the meaning of the 'model' parameter, leaving some 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 provides descriptions for three of four parameters (code, context, timeout), covering 75%. The tool description does not add new parameter insights or explain the missing 'model' parameter. Thus it adds minimal value beyond the 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 clearly identifies the tool as asking Grok to adversarially break code, listing specific types of issues (edge cases, race conditions, security holes, adversarial inputs). This distinguishes it from sibling tools like grok_chat (general chat) and grok_review (code review), giving a clear and specific purpose.

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 is provided on when to use this tool versus alternatives like grok_consult or grok_review. The description does not mention prerequisites, limitations, or when not to use it, leaving the agent without decision-making context.

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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