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, yet it only states the computation formula and says to provide inputs. It does not describe the output format, label requirements (binary vs. multi-class), error behavior, or side-effect profile. It also introduces a description-vs-schema mismatch: it says to provide 'arrays' while the schema types are strings, which could mislead an agent constructing the call.

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?

Two sentences, with the core computation stated upfront and the input guidance second. The 'F1 Score:' prefix redundantly repeats the tool's name, creating mild waste, but the description remains tight and every clause earns its place. Front-loading of the mathematical definition is effective.

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?

For a simple calculator tool with no annotations and no output schema, the description covers the core computation and names the relevant inputs. But it leaves real gaps: no return-value description, no disambiguation of the four-parameter schema, and the contradictory claim that inputs are arrays when the schema declares strings. An agent could invoke it with the wrong parameter pairs or wrong types.

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%, so the baseline is 3, but the schema descriptions ('YPred to process', 'Actual to process') are pure tautologies adding no meaning. The description does add value by naming which parameters to use (yTrue and yPred), partially resolving the ambiguity created by the four redundant alias parameters. However, it never addresses the duplicates (actual/predicted), the fact that no parameters are required, or the arrays-vs-strings type conflict.

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 specific verb (Calculate), the resource (F1 score), and a precise mathematical definition ('harmonic mean of precision and recall'). The definition inherently separates it from sibling metric tools like x402-precision, x402-recall, and x402-confusion-matrix, though it never names them explicitly. Loses a point for not directly differentiating itself from those closely related siblings.

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 offers no guidance on when to choose this tool over alternatives such as x402-precision, x402-recall, or x402-roc. 'Provide yTrue and yPred arrays' is an input instruction, not a usage-selection guideline. An agent has no information about which scenarios warrant F1 versus other classification metrics.

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