get_activity_streams

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

With no annotations, the description carries the full burden and does well by explaining the return format, listing stream types, and clarifying that omitting streams fetches all. It doesn't mention error handling or auth, but the read-only nature is clear and the behavioral details are solid.

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?

The description is well-structured with a clear opening, explanatory note, bulleted stream list, and Args/Returns sections. It's detailed but every element serves a purpose, with no fluff.

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 two-parameter tool with an output schema, the description covers purpose, parameters, and return type comprehensively. It misses explicit sibling differentiation and edge-case behavior, but overall it's complete enough for an agent to select and invoke correctly.

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 100% schema coverage, the description adds significant meaning by enumerating each valid stream type with its unit/meaning (e.g., 'watts: Power data'), which the schema alone doesn't provide. It also confirms the default behavior of the streams parameter.

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 opens with a specific verb and resource: 'Get time-series data streams for an activity.' It lists all stream types, clearly distinguishing this from sibling tools like get_activity_details or get_activity_intervals by focusing on raw time-series data.

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?

States the data is 'essential for detailed workout analysis and visualization,' providing clear context for when to use the tool. However, it does not explicitly name alternatives or exclusion criteria, so it lacks the explicit when-not-to-use guidance.

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