Verify if your Marvin API token is valid. Returns OK when authentication succeeds, helping you confirm connection credentials before using other tools.
Test authentication against Marvin's API. Returns OK if the apiToken works.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
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No arguments | |||
Changes observed during successful MCP inspections.
v1.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=false, establishing this is a safe, read-only operation. The description adds the valuable behavioral detail that the tool returns OK only if the apiToken is valid, giving the agent expectation about success criteria without over-specifying.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences, front-loaded with the action and resource, followed by the result condition. Every word earns its place. No filler or redundant restatement.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-parameter, read-only, output-schema-equipped tool, this description is fully sufficient. It states the purpose, the success indicator, and is complemented by the annotations. Nothing else is needed for an agent to select and call it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
There are zero parameters, so the schema trivially covers 100%. The description does not need to elaborate on parameters. The baseline for zero-parameter tools is 4 because no parameter ambiguity exists.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb and resource: 'Test authentication against Marvin's API.' It clearly states what the tool does and distinguishes it from the sibling tools, none of which are connection/auth checks. The success condition ('Returns OK if the apiToken works') further clarifies the behavior.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description clearly communicates when to use this tool: when you need to verify authentication or API token validity. It does not explicitly exclude alternatives, but no sibling tool exists for this purpose, so the context is sufficient.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.