apple_photos_update

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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is largely covered. The description adds genuine value beyond them by noting the iCloud Photos sync side effect and by saying keywords are 'replaced' rather than merged. It still does not say whether omitted fields are preserved or whether permissions are needed.

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 tight sentences with no filler; the field list is front-loaded and the sync caveat is appropriately secondary. Nothing is redundant, though it is terse enough that some needed detail is missing rather than trimmed.

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 destructive, idempotent mutation with no output schema, the description covers the affected fields and one side effect, which is adequate. It stops short of telling the agent whether unspecified fields remain untouched and what the destructive keyword replacement means for existing data, which would complete the picture.

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 0%, so the description carries the burden and maps four of five parameters (name as 'title', description, favorite, keywords) to meaningful actions. It even clarifies that keywords are replaced wholesale. However, it omits the required mediaId and gives no format or constraint details, leaving gaps it could have filled.

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?

A clear verb (update) plus resource (Photos media) and an explicit enumeration of the mutable fields (title, description, favorite, keyword list). An agent can immediately tell what the tool changes. It does not differentiate from any sibling, though none of the photos siblings perform updates, so the risk of confusion is low.

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?

No when-to-use guidance, prerequisites, or alternatives are given. The only usage-adjacent signal is 'and/or', implying fields are optional, which the agent must infer rather than being told. There is no statement of when this tool should be preferred over apple_photos_add_to_album or other mutations.

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