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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety behavior is covered without description help. The description adds a content hint about the returned detail, but since an output schema exists that enumerates return values, this is partly duplicative rather than genuinely new behavioral context.

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 zero filler; the payload contents are front-loaded and the routing hint to the sibling follows immediately. Every clause earns its place.

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 one-parameter read tool with a full output schema and rich annotations, the description covers what is returned, where the id comes from, and which sibling handles the adjacent use case. Nothing needed to invoke it correctly is missing.

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?

There is a single parameter at 100% schema coverage, and the description's only param statement ('Id comes from ourpr_list_runs') restates the schema description verbatim. It adds no format, constraint, or ID-shape guidance beyond what the schema already provides.

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 states a specific resource and scope ('One activity in full') and enumerates the returned detail (mile splits, heart rate, cadence, calories, device). It is clearly differentiable from the sibling ourpr_run_stream, though it never uses an explicit retrieval verb and leans on the title for the action.

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?

It names the prerequisite source for the id ('Id comes from ourpr_list_runs') and explicitly routes the alternative use case to ourpr_run_stream for route profile data. No exclusion is given for other siblings (e.g. ourpr_run_laps), so it falls just short of a full when/when-not statement.

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