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

readOnlyHint=true already declares this as a safe read, so the bar is lower; the description adds the underlying endpoint (GET /day_notes) and clarifies what a 'day note' is. It says nothing about pagination behavior or result size, though the limit/offset schema fields partly cover that.

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?

A single compact sentence that front-loads the resource and its definition, followed by the endpoint as a trailing detail. Nothing is wasted.

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 full schema coverage and no output schema, the description supplies the domain meaning of 'day notes' and the location filter, which is enough to call it correctly. Only minor gaps (pagination/return shape expectations) remain.

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 all five parameters (start, end, limit, offset, location) are already documented in the schema. The description only echoes the location filter ('optionally for one location') without adding format or default semantics beyond what the schema provides, making the baseline 3 correct.

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 clear verb+resource ('List day notes') and, crucially, defines the domain term by example ('notices pinned to rota dates, e.g. events or deliveries'). This makes the resource distinguishable from siblings like list_days_off or list_shifts, though it does not explicitly name a sibling to contrast with.

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?

'optionally for one location' implies the filtering context, and the resource is distinct enough from siblings that misuse is unlikely. However, there is no explicit when-to-use/when-not statement or named alternative, so guidance remains implicit.

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