live_activity_update

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

No annotations are provided, so the description carries the full behavioral burden. It is silent on whether this needs API credentials, what ending the activity does, whether updates are reversible, and typical latency/rate limits for a write against a live user-facing surface.

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, purpose first and use cases second, with zero filler. Appropriately sized for the information it chooses to convey.

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 nine-parameter mutation tool with a nested notification object, no annotations and no output schema, the description leaves too much uncovered. It should at minimum signal that ending an activity is irreversible and that authenticated API credentials are required.

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 89%, so the schema already documents most parameters including apiKey, app_id, activity_id, stale_date, dismissal_date and end_activity. The description only loosely hints at what content_state holds (scores, delivery status) and adds no format or syntax beyond the schema, so the baseline 3 applies.

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 ('Update') and resource ('iOS Live Activity'), so the operation is unambiguous. It does not need to differentiate from siblings since none of the listed tools touch Live Activities, but it also does not explicitly claim that territory.

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?

'Used for real-time updates like sports scores, delivery tracking' gives the usage context and implies when to reach for it. It stops short of stating prerequisites, when-not-to-use, or any alternative, leaving the selection logic incomplete.

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