create_track_selection

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the behavioral nuance that the selection does not copy the GPX data and that it is a continuous subsection, which is useful context beyond the annotations. No contradiction exists.

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 concise sentence with no filler and the core action is front-loaded. However, for a tool with 10 parameters and no schema documentation, the brevity leaves important context unaddressed, so it is not a perfect structure for this complexity.

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 not complete enough for correct invocation. It does not explain how to specify the continuous subsection (e.g., by coordinate pair, time range, or point indices), what relationship the selection has to later sibling tools, or what the output represents. While annotations and the output schema reduce some burden, the 10-parameter surface with 0% schema coverage demands more context.

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%, so the description carries the full burden for explaining the 10 parameters. It provides no information about how start_lat/start_lon, start_time, start_point_index, and their end_ counterparts relate to one another, which parameters are required, or how the selection determines the subsection. Parameter names are somewhat self-explanatory, but that is not sufficient compensation.

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 clear verb and resource: 'Select one continuous subsection of an analyzed GPX.' The qualifier 'without copying it' adds useful distinction. However, it does not explicitly differentiate the tool from sibling tools like match_track_selection or analyze_gpx_track.

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 description gives no explicit guidance on when to use this tool versus alternatives, and it does not mention prerequisites or follow-up steps. The phrase 'of an analyzed GPX' only weakly implies that analysis must happen first, which is not enough for confident tool selection.

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