stream_heart_rate

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

With no annotations provided, the description carries full burden and effectively discloses behavioral traits: buffering of last 5 minutes, network-dependent latency (10-60 s), and that it runs HealthKit observer. No contradictions; only minor omission of error conditions.

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?

Description is well-structured: first sentence states purpose, followed by details, a note on latency, and clear Args/Returns sections. Every sentence is necessary and front-loaded.

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?

Given one optional parameter, no enums, and an output schema (not shown but mentioned as JSON array), the description covers return format and key behavior. Could mention error handling or prerequisites (e.g., Apple Watch availability) but still above average.

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?

Despite 0% schema coverage, the description adds context beyond the schema: duration_seconds has a valid range of 1-300 and a default of 30. This compensates for the schema's lack of description.

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 uses specific verb 'collect' and resource 'heart rate readings from Apple Watch', clearly distinguishing from sibling tools 'get_heart_rate' (likely single reading) and 'get_heart_rate_history' (historical data) by focusing on streaming over a time window.

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?

While the description implies it's for real-time monitoring with buffered readings and latency explanation, it lacks explicit guidance on when to use this tool versus siblings. Usage context is inferred but not stated.

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