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 adds meaningful behavioral detail: the tool maps to a GET endpoint and does not require an API key, which signals a read-only, unauthenticated operation. It could mention that providing an optional api_key is allowed but unnecessary, yet the schema already makes that parameter optional with a default.

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 sentences with no filler: the core purpose is front-loaded, followed by the key behavioral detail about authentication. Every sentence earns its place, and the description is appropriately sized for a simple version-check tool.

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 tool with one optional parameter and an output schema present, the description is complete. It tells the agent what the tool does, how it maps to the HTTP API, and whether authentication is needed. No critical information for correct invocation is missing.

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?

Schema description coverage is 100%, so the baseline is 3. The description reinforces that no API key is required, which clarifies the optional parameter's semantics, but it adds no new details beyond what the schema already states. This aligns with the calibration baseline where the schema does the heavy lifting.

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 states a specific verb ('Get') and resource ('current API version'), which is unambiguous and distinct from all sibling tools. The title and description align exactly, and the scope is clear without needing to inspect the schema.

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 clear context by mapping the tool to GET /version and explicitly stating that no API key is required. This tells an agent when the tool can be used (without authentication) and implies it is a lightweight read operation. It does not explicitly name alternatives, but none are plausible for this unique operation.

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