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

The readOnlyHint=true annotation already establishes this is a safe read. The description adds the upstream API route (GET /v2/summary/sleep/{user_id}), which is useful for documentation cross-referencing, but says nothing about pagination, data latency, empty-result behavior, or the shape of a 'summary'.

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?

Two short, front-loaded sentences with no redundancy — purpose first, API route second. The route sentence is marginally useful rather than filler, though a dangling NoSuchMethod-style detail like this could be trimmed in favor of usage guidance.

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?

With no output schema, the description carries the burden of explaining what a 'sleep summary' contains, and it does not — no field list, no note on whether results are per-day records. Annotations cover the safety profile and the schema covers inputs, so the definition is callable but leaves the return contract unspecified.

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 user_id, start_date, end_date, and provider are all fully documented in the schema itself, including the absolute date pattern and the upstream default for end_date. The description only restates that a date range applies, adding no meaning beyond the schema. 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?

States a specific verb and resource ('Get sleep summaries for a user over a date range') plus the underlying API route, so the agent knows exactly what data class this returns. It does not explicitly contrast itself with sibling retrieval tools like vital_get_activity or vital_get_timeseries, but the 'sleep' resource is unambiguous.

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 no when-to-use guidance, no mention of when to prefer vital_get_timeseries or vital_get_user_latest_info instead, and no note on how to choose dates or the provider filter. Without this, the agent must infer selection from the tool name alone.

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