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

Annotations already declare read-only, idempotent, non-destructive, and closed-world behavior. The description adds useful context beyond that: default date is today, date format is YYYY-MM-DD, type filters to one of ten named event types, and the return is the exact log rather than a summary. It omits ordering, pagination, and timezone details, but adds meaningful behavioral value over annotations.

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?

Three compact sentences, front-loaded with the core action and default, followed by filter details and return semantics. Every clause adds needed information with no filler.

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 2-parameter read-only tool with no output schema, the description covers the default date, date format, filter options, and return nature (raw list, not summary). An agent has enough to invoke correctly; missing ordering and pagination are minor for this simple read.

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 0%, so the description must fully compensate. It does: `date` is YYYY-MM-DD with default today; `type` is an optional single-event filter with an explicit list of valid values (milk, sleep, wake, poop, nappy, solid, note, supplement, weight, length). Both parameters are fully documented.

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 (Get) and resource (raw event log for one day), explicitly distinguishes from summary tools ('not a summary'), and enumerates the filterable event types. An agent can identify this as the raw daily log tool without checking siblings.

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?

Clear context: use for raw event log by day, default today, optionally filtered to one type. The 'not a summary' clause implicitly routes against summary-oriented siblings like get_today or get_week_review, but no alternative is named explicitly, so no explicit when-not guidance.

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