get_latest_activity

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

With no annotations, the description must disclose behavioral traits, but it only says 'fetches', implying a read operation. It does not describe the return structure (e.g., fields in the 'summary'), whether an empty result is possible, or any limitations. This is minimal disclosure for a tool with no output schema or annotations to supplement.

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 a single sentence with no redundant words or filler. It delivers the core purpose immediately and is appropriately sized for a simple, parameterless tool.

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?

The description is minimally adequate: it tells the agent what the tool does but omits any mention of return values or edge cases (e.g., absence of recent activity). The presence of output schema would have helped, but since it is absent, the description could have been more informative about what the 'summary' contains. However, for such a simple tool, this is barely sufficient.

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?

The tool has zero parameters, so the description does not need to explain parameter meanings. Per the rubric's baseline for 0 params, a score of 4 is appropriate; the description correctly avoids unnecessary parameter details.

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 clearly identifies the action ('Fetches') and the resource ('most recent workout session and summary'), which distinguishes it from list-oriented siblings like 'list_recent_activities'. However, it does not explicitly name any alternative tools or further differentiate among the many get_* tools, so it falls just short of a 5.

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?

There is no guidance on when to use this tool versus alternatives such as 'list_recent_activities' or 'analyze_activity_drift'. The description provides no context about typical use cases, prerequisites, or situations where another tool would be more appropriate, so it fails to help the agent choose correctly.

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