get_current_glucose

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 does this well by explaining what the tool returns: current glucose in mg/dL, trend direction, and in-target status. It doesn't discuss side effects or error scenarios, but for a read-only getter, the behavior is transparent and the output is clearly specified.

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 two sentences, both valuable. It front-loads the primary action ('Get the most recent glucose reading') and then immediately provides the key return details and the intended use case. There is no redundant or filler content; every clause earns its place.

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 the tool's simplicity (no parameters, no annotations, no output schema), the description is complete. It explains what it returns, the unit of measurement, and the use case. It also positions the tool among siblings by focusing on 'most recent' and 'real-time,' covering all necessary context for an agent to select and invoke 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?

The tool has zero parameters, so the description is not required to explain parameter semantics. The baseline for zero parameters is 4, and the description appropriately focuses on the output rather than input. No additional parameter clarification is needed.

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 a specific verb and resource: 'Get the most recent glucose reading from your FreeStyle Libre sensor.' It further distinguishes itself from siblings by focusing on the current reading, not history, stats, or trends. It also enumerates the returned data (value, trend, target range), making the purpose unmistakable.

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 explicitly identifies the use case: 'Use this for real-time glucose monitoring.' This gives clear context for when to use the tool. It doesn't mention alternatives or exclusions, but the real-time focus implicitly differentiates it from historical tools like get_glucose_history or aggregation tools like get_glucose_stats.

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