Modify an existing iCloud reminder by ID, changing only the fields you provide while preserving all other details.
Update an existing reminder. Only provided fields are changed; others are preserved.
| Name | Required | Description | Default |
|---|---|---|---|
| due | No | ||
| notes | No | ||
| title | No | ||
| listName | Yes | List name containing the reminder | |
| priority | No | high, medium, low, or none | |
| reminderId | Yes | Reminder ID to update |
Changes observed during successful MCP inspections.
v2.8.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full behavioral burden. It does disclose genuinely useful patch semantics ('Only provided fields are changed; others are preserved'), which tells the agent this is a partial rather than full replacement. It says nothing about required permissions, whether the change is reversible, or what happens on an invalid reminderId, so significant gaps remain.
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 with zero waste, and the patch-behavior clause is front-loaded right after the purpose statement where it matters most. Nothing is padded or redundant.
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 six-parameter mutation tool with no annotations and no output schema, the description covers the single most important behavioral trait (partial update) but omits parameter guidance, auth requirements, and error behavior. It is adequate but visibly thin for the tool's complexity.
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 only 50%, so due, notes, and title are undocumented in both the schema and the description. The description refers generically to 'provided fields' without naming a single parameter or adding format/semantic detail over the schema, so it does nothing to close the coverage gap.
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 ('Update an existing reminder'), which is clear and unambiguous on its own. It does not, however, distinguish itself from the adjacent mutation siblings complete_reminder, delete_reminder, or create_reminder, leaving the agent to infer the boundary from the name alone.
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 offers no when-to-use or when-not-to-use guidance and names no alternative. The most important routing question for this tool — update versus complete versus recreate a reminder — is left entirely to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.