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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description does add real behavioral context beyond them: the $0.001 USDC x402/Solana price per successful call and a parallel HTTPS endpoint, which matter for planning and cost.

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?

Front-loaded with the operation and formula, followed by examples, then pricing/transport. Nearly every sentence earns its place; the payment/endpoint sentence is useful operational detail rather than padding.

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?

With no output schema, the description makes the return value obvious (the integer determinant) via the formula and examples. For a one-parameter math tool with annotations covering safety, that is close to complete, though edge-case behavior for malformed input arrays is unstated.

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 0%, and the single 'matrix' parameter is only typed as an integer array with maxItems 4 and no minItems. The description compensates by defining the element order as [a, b, c, d] and demonstrating it with examples, which is the crucial semantic. It does not address arrays shorter than four elements or the range limits.

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?

States a specific verb+resource (computes the determinant) and even gives the formula ad-bc plus the exact input convention [a,b,c,d]. It does not differentiate itself from close siblings like sl2_trace, sl2_mul, sl2_inv, or matrix_ops, so an agent must infer the distinction.

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 two worked examples ([1,1,0,1]→1, [2,0,0,3]→6) clarify input interpretation but say nothing about when to choose this over sl2_trace or matrix_ops. There are no exclusions, prerequisites, or alternative-selection guidance.

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