QR Code By API Ninjas MCP Server

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. It mentions that the tool 'returns a QRCode image binary,' which implies a read-only operation, but doesn't disclose important behavioral traits like rate limits, authentication requirements, error handling, or what 'binary' means in practice (e.g., base64 encoding, raw bytes). The description is minimal and leaves critical behavioral aspects unspecified.

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?

The description is a single, efficient sentence that gets straight to the point: 'API Ninjas QR Code API endpoint. Returns a QRCode image binary specified by input parameters.' It's appropriately sized and front-loaded, with no wasted words. However, it could be slightly more structured by explicitly mentioning the core function first, so it doesn't achieve a perfect score.

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?

Given that there are no annotations and no output schema, the description is incomplete for a tool with 5 parameters. It doesn't explain what the return value looks like (e.g., format of the binary, potential errors), nor does it provide behavioral context. The description is too minimal to adequately support an AI agent in using this tool 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?

The input schema has 100% description coverage, with all 5 parameters well-documented in the schema itself. The description adds no additional parameter semantics beyond what's already in the schema. According to the scoring rules, when schema_description_coverage is high (>80%), the baseline is 3 even with no parameter info in the description.

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 clearly states the tool's purpose: 'Returns a QRCode image binary specified by input parameters.' It specifies the verb (returns), resource (QRCode image binary), and scope (specified by input parameters). However, it doesn't distinguish from siblings since there are none, so it cannot achieve the full differentiation required for a score of 5.

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 provides no guidance on when to use this tool versus alternatives. It simply states what the tool does without mentioning any context, prerequisites, or exclusions. There are no siblings to compare against, but the description still lacks basic usage context.

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