Morning briefing

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description need not restate that. It adds value by disclosing concurrent fetching, per-section error handling (sectionsUnavailable), and behavior for unrecorded sections. It also clarifies that it returns numbers only, which is a behavioral trait. No contradiction with annotations; the description complements them well.

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 three short paragraphs. The first sentence immediately states the purpose and scope. The second paragraph explains concurrency and error handling, the third clarifies return content and advice. It is front-loaded and each sentence earns its place, though the lack of parameter explanation is a structural omission that prevents a 5.

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 an aggregate read tool with an output schema, the description covers the main behavior: what it returns (numbers only), concurrency, and error handling. However, it omits any explanation of the optional 'date' parameter, which is essential for correct invocation. Since the parameter is optional and has a default, an agent might infer it defaults to today, but this is not explicit. Overall, the description is adequate for the primary use but incomplete regarding parameters.

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 a single optional 'date' parameter with 0% schema description coverage. The description does not mention the date parameter at all, leaving its meaning and format entirely to the schema (which only specifies type string/null and default null). An agent has no guidance on how to format the date or what it controls (presumably which day's briefing). This is a significant gap given low schema coverage.

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: 'Morning snapshot in one call' listing the specific metrics (sleep, HRV, Body Battery, readiness, stress, RHR). It distinguishes itself from siblings by aggregating six data types into a single call, and explicitly notes it returns numbers only, no training advice. This is a precise, non-tautological statement.

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 explains when to use it: for a quick 'how am I doing today?' question, and highlights the efficiency benefit of one round trip vs six. It also advises reading readiness, HRV, and Body Battery together, which is domain guidance. It does not explicitly name alternative tools for individual metrics, but the context implies that separate tools exist for each metric. This is clear usage context, though not exhaustive.

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