Pod and CGM sensor changes

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

With no annotations provided, the description shoulders the transparency burden and does well: it discloses that events are point-in-time markers, that times are 'plain wall clock time (device-local), not UTC,' and that the result contains podChanges/sensorChanges arrays plus a count. It also explains the intended interpretation to prevent misuse. It does not mention pagination or ordering, but for a simple read-only list tool that is not a major gap.

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 organized into short paragraphs: what is returned, when to use it, timezone caveat, and return shape. It is front-loaded and avoids fluff, though the middle paragraph on clinical context is somewhat extended. Overall it is efficient and readable.

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 no output schema and no annotations, the description compensates by specifying the return structure (two arrays and counts), the timestamp semantics, and the practical use case. It also warns against over-interpretation. The tool is simple enough (two required params, no nested objects) that nothing critical 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?

The input schema already documents start and end in detail, including ISO 8601 format, inclusive bounds, ordering, and the wall-clock caveat. The description reaffirms the wall-clock caveat but adds no new parameter-specific semantics beyond the schema's 100% coverage, so a baseline 3 is appropriate.

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 exactly what the tool provides: 'Pod changes ... and CGM sensor changes, as timestamped events, kept as two separate lists.' It also clarifies these are point-in-time markers, not amounts, and names the returned fields (podChanges and sensorChanges), so the agent understands the resource without ambiguity. This clearly distinguishes it from sibling glucose/insulin tools by subject matter.

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 gives a concrete use case: use the events as 'CONTEXT for nearby glucose disruption' to check whether an unexplained high or odd readings 'lines up with a recent change.' It also tells the agent how to interpret results ('possible contributing factor, never assert it as the cause'). It does not name explicit exclusions or sibling alternatives, but among the visible siblings none overlap directly with device-change events, so the omission is minor.

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