list_activities

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

With no annotations, the description must carry the behavioral burden, and it does add ordering and pagination behavior. However, it never explicitly says the operation is read-only, and it does not describe the return shape (e.g., summaries vs. full activity objects), which are meaningful gaps for an unannotated tool.

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 compact and well-structured: a single purpose sentence followed by a compact argument list. Every line provides useful information, and the primary purpose is 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?

For a four-parameter tool with no output schema and no annotations, the description covers the main call surface well. However, it leaves the response payload type ambiguous—what fields or summary level are returned—and says nothing about authentication or error conditions, so an agent cannot fully predict downstream behavior.

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 0%, and the description compensates fully: it defines page and per_page with defaults and range, and crucially explains before and after as optional Unix timestamps filtering activities by time. Every parameter gains semantic meaning beyond the raw JSON schema.

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 a specific verb and resource—'List the athlete's activities'—and states the ordering ('most recent first'). This clearly distinguishes it from singular-fetch siblings like get_activity and from data-detail tools such as get_activity_streams.

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?

The applicable context is clear: this is the bulk listing/paging tool for an athlete's activities, with time-range filters for narrowing the window. It does not explicitly name alternatives or state when not to use it, so it stops short of a perfect 5.

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