plot_heatmap

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool renders a heatmap but doesn't describe what happens (e.g., outputs an image file, displays in UI, returns a URL), performance characteristics, or any side effects. The example shows input structure but lacks context on the rendering process or output format.

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 appropriately sized and front-loaded: the first sentence states the purpose clearly, followed by a brief note on parameter structure and a comprehensive example. Every sentence earns its place, though the 'Simple flat parameters' note could be more integrated with the purpose statement.

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 the tool's moderate complexity (visualization with 8 parameters), no annotations, and an output schema present (which handles return values), the description is reasonably complete. It covers the core purpose, parameter structure via example, and distinguishes the tool type. However, it lacks behavioral context and usage guidelines, which are gaps for a tool with no annotations.

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 must compensate. It provides a clear example with all required parameters (matrix, x_labels, y_labels, title) and hints at optional ones (width, height, color_scale, show_values through defaults in the example). This adds significant meaning beyond the bare schema, though it doesn't explicitly document all 8 parameters or their semantics in text.

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 the tool's purpose: 'Render 2D matrix as color grid.' It specifies the verb ('render') and resource ('2D matrix'), and distinguishes it from siblings by mentioning it's for heatmaps (color grids) rather than other plot types like bars or lines. However, it doesn't explicitly differentiate from plot_contour, which might also visualize matrices.

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 no guidance on when to use this tool versus alternatives like plot_contour or other visualization tools. It mentions 'Simple flat parameters - no nested objects!' which hints at parameter structure but doesn't help with tool selection. No explicit when/when-not instructions or sibling comparisons are included.

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