token_exists

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'check if exists' without specifying the return format (e.g., boolean, status code), error behavior for invalid/missing tokens, or whether this involves a network call. The absence of any such details leaves significant ambiguity about the tool's runtime behavior.

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, six-word sentence that is extremely concise and front-loaded. Every word earns its place, and it avoids any extraneous detail, making it easy for an agent to parse quickly.

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 simple existence check with one required parameter and no output schema, the description is adequate but not fully complete. It doesn't state what the return value represents (e.g., does it return 'true'/'false' or a 200/404 status?) or any error conditions. Given the absence of an output schema, the description should have clarified the response format.

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 schema already fully describes the single parameter (tokenId) with a clear description. The tool description adds no additional semantic value beyond what the schema provides, so the baseline score of 3 applies. There is no need for further compensation given 100% schema coverage.

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 ('Check') and resource ('if a StarGate NFT token exists'), clearly stating the tool's exact purpose. It distinguishes itself from sibling tools like nft_check_ownership or nft_get_metadata by focusing purely on existence rather than ownership, metadata, or other attributes.

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 doesn't mention use cases, prerequisites, or why one would choose this over nft_check_ownership or vechainstats_get_nft_info. Users are left to infer the intended context.

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