plot3d_expression

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

No annotations are provided, so the description must carry the transparency burden. It does disclose that the output is a base64 PNG and that it plots a 3D surface, but it doesn't mention computational intensity, error handling, or behavior regarding sessions. This is adequate but not rich.

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 that is front-loaded with the core action and includes the key output detail. Every word is meaningful and there is no fluff.

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 output schema exists (as noted), the description need not explain return values. The description, combined with the rich parameter schema, provides enough context for an agent to select and invoke the tool correctly. It lacks only minor behavioral nuances, but for a plotting tool with this schema, it's fairly 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 description coverage is 100% because every parameter has a description. The description adds no additional meaning beyond what the schema already provides, such as details about the expression format or variable names, so baseline 3 is appropriate.

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 'Plot' with a clear resource '3D surface of a two-variable expression' and specifies the output format 'base64 PNG'. This clearly distinguishes it from siblings like plot_expression (likely 2D) and plot_multi_expression (multiple expressions).

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 implies its usage context by stating it's for a 3D surface of a two-variable expression, which clearly separates it from 2D or multi-expression plotting tools. However, it doesn't explicitly mention when not to use it or name alternative tools, so it falls just short of a 5.

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