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

readOnlyHint=true already establishes the safe-read profile, so the description only needs to add context beyond that. It adds the endpoint and the collection taxonomy but says nothing about pagination behavior, range defaults, or rate limits beyond what the schema's next_token/start_date descriptions already state.

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 sentences, front-loaded with the core action and the selection guidance, ending with the endpoint. The long collection enumeration is dense but every clause earns its place by disambiguating the required parameter.

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 read-only list tool with 100% schema coverage and no output schema, the description covers purpose, collection selection, and the endpoint. Return-value shape and pagination semantics are left entirely to the schema, which is acceptable given there is no output schema to explain.

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 coverage is 100%, so the baseline is 3. The description goes beyond the raw enum by grouping values semantically ('daily_sleep and sleep for sleep, daily_readiness for recovery, daily_activity for movement'), which genuinely helps the agent choose the right collection rather than parsing a flat 16-value enum.

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?

Starts with a specific verb+resource ('List documents from one Oura collection over a date range') and explicitly positions itself as 'the main read,' distinguishing it from the singular oura_get_document sibling. The endpoint mapping (GET /v2/usercollection/{collection}) reinforces the exact operation.

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?

'This is the main read' gives clear context for when to reach for this tool, and the collection-by-goal mapping tells the agent which value to pick for sleep, recovery, movement, load, etc. It lacks an explicit when-not / named-alternative statement (e.g., deferring to oura_get_document for a single item), so it stops short of a 5.

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