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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds no behavioral context beyond the operation list, such as operation-specific input requirements (e.g., matrix_b needed for multiply/add, square matrix required for inverse/determinant) or dimension constraints.

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 front-loaded sentence that enumerates operations with zero filler. It is appropriately sized for a general-purpose matrix calculator.

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 an output schema and full parameter descriptions, the description need not explain return values or basic params. However, for a multi-operation tool surrounded by dedicated siblings, it should clarify routing and operation-dependent parameter requirements, which it does not.

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 schema already documents matrix_a, matrix_b, and the operation enum. The description repeats the operation list but adds no extra semantics such as when matrix_b becomes required or shape rules, so the 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 states a clear resource (matrix operations) and enumerates the supported operations, so the agent knows exactly what it does. It does not differentiate this general tool from the many dedicated matrix siblings such as calculator_matrix_multiply or calculator_eigenvalues, which keeps it from a 5.

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?

There is no explicit guidance on when to use this general matrix tool versus the numerous operation-specific siblings. The description only lists operations, leaving the agent to infer routing without any stated alternatives or exclusions.

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