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

No annotations are provided, so the description carries the full burden. It entirely fails to disclose behavioral traits: it doesn't mention that this is a read-only operation, that it fetches health data, that it might return large volumes, that there are per-call costs, or what the response shape (daily aggregates vs minute-level) implies. The only behavioral hint is the cost per call in the description, which is minor. The rich parameter docs do not substitute for a description of tool 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 extremely short — arguably under-specified rather than concise. It provides no front-loaded information; the only content is a product name and a price. While it is brief, the brevity is not a virtue because it omits the tool's core function. A useful description could be a single sentence stating the purpose while remaining concise.

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?

The tool has 8 parameters (all optional) and no output schema, yet the description gives the agent no sense of what to expect in return, when to use this over siblings, or any behavioral context. The parameter docs are rich, but the description fails to provide the high-level context needed to decide whether to invoke. There's no mention of output type, typical use cases, or relationship to metabolic_overview and health_insights.

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 for this dimension is 3. The description adds no parameter meaning beyond the schema. However, the schema itself is unusually detailed, with per-parameter explanations and caveats (e.g., cgm_minute not included by default, cgm_minute_resolution buckets averaging). Since the description provides zero added value, but the schema already covers semantics fully, a 3 is warranted.

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 'Sally skill ($0.001/call)' is a tautology that restates the tool name and provides only a vague notion of a 'skill' with a cost. It fails to state a specific verb and resource, making it impossible for an agent to understand what the tool actually does without inspecting the schema. It does not distinguish from siblings like health_insights or metabolic_overview.

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?

There is no guidance on when to use this tool versus alternatives. The description offers no context, exclusions, or trade-offs. The agent must guess whether to call this or health_insights etc. Some usage context is buried in parameter descriptions (e.g., 'cgm_minute is opt-in'), but that does not cover tool-selection guidance.

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