CGM connection status

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it reports mock vs live data, whether credentials are present, and provider-specific env/region. This enriches the agent's understanding without contradicting the annotations.

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, well-structured sentence that front-loads the core purpose and packs in the key details (provider, selection reason, credentials, mock vs live, env/region) without any fluff. Every word earns its place, and the structure is easy to parse.

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 status tool with one optional parameter and no output schema, the description covers the main return items (provider, reason, credentials, mock/live, env, region). It does not specify the exact return format, but that is typically inferred for status tools. The description is adequate for an agent to 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?

The input schema has 100% description coverage, so the parameter privacy_mode is already well-documented. The description does not add extra meaning about the parameter beyond restating its purpose. The schema fully explains the enum values, so the description adds no significant value here.

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: reporting the active CGM provider, selection reason, credential presence, and mock vs live data, with provider-specific details. It uses a specific verb ('reports') and resource ('active CGM provider'), and the details (Dexcom env, Libre region) distinguish it from broader tools like cgm_capabilities or cgm_libre_status.

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 implies usage for checking connection status but does not explicitly state when to use it versus alternatives. It does not mention sibling tools or exclusions, so the agent must infer from the tool's name and description that it is the go-to for connectivity status. No explicit guidance is provided.

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