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

Annotations already declare the write profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=false). The description earns credit for adding genuine PATCH semantics — 'Only the fields you pass are changed' — which is not derivable from the annotations and materially changes how an agent constructs the call.

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 sentences, zero padding, with the change-scope caveat placed where it will be read. It is arguably over-terse for a mutation tool, but nothing in it 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?

An output schema exists, so return values need not be described. However, the tool carries an approval_id parameter tied to the human-approval flow and the description never mentions this prerequisite or the single-use nature of that credential — a real gap for a mutation tool.

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 the baseline is 3. The description loosely maps to three of the seven parameters (title, date, recurrence) but adds no format or constraint detail beyond the schema, and says nothing about approval_id.

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 states a specific verb+resource ('a reminder needs changing') and enumerates the mutable facets (title, date, recurrence), making it distinguishable from reminders.create/delete/get. It stops short of naming those siblings explicitly, so it is clear but not differentiated by name.

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?

'When a reminder needs changing' implies the trigger but states no exclusion or alternative — it never tells the agent to use reminders.create for new reminders or reminders.get for reads. Usage is inferable from context rather than stated.

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