add_sparkline

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

Without annotations, the description discloses that the tool 'Writes objects.sparkline with the line measure + category bindings', which is a meaningful behavioral detail about what gets modified. However, it does not mention potential side effects, overwriting behavior, or prerequisites (e.g., whether an existing sparkline is replaced), leaving some transparency gaps.

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 two sentences, front-loaded with the primary action and purpose. Every sentence contributes value, with no filler or redundant restatement of the tool name. It efficiently conveys the core mechanism and parameter roles.

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?

Given no output schema and no annotations, the description covers the essential behavior, target visual type, and key parameters. It explains what the sparkline represents and how it is bound, which is sufficient for an agent to select and invoke the tool. Some minor missing details like the optional lineColor default are covered by the schema, so the description is reasonably complete.

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 coverage is high (88%), but the description adds domain-specific meaning by clarifying that 'valueTable/valueMeasure = the line measure' and 'categoryTable/categoryField = the axis'. This goes beyond the raw schema field names and helps an agent understand the roles of the parameters in the sparkline context.

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 states a specific verb+resource: 'Add a NATIVE SPARKLINE column to a table/matrix'. It explains what a sparkline is ('a per-row mini line driven by a value measure across a category') and distinguishes from similar sibling tools like add_svg_sparkline by emphasizing 'NATIVE'.

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 provides clear context: it is for adding a native sparkline to a table/matrix, with a typical use case ('trend over month'). It does not explicitly name alternative tools, but the 'NATIVE' qualifier implies when this tool is appropriate, giving the agent enough context to distinguish it from SVG-based sparkline tools among siblings.

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