add_numbers

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

No annotations are provided, so the description carries the full burden; it discloses determinism and absence of side effects, which is genuinely useful for an agent deciding whether to batch or retry. It does not mention error conditions (e.g., integer overflow beyond the stated 32-bit range), but the schema documents the range, so this is a minor gap.

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?

Three sentences, front-loaded with the operation and immediately followed by usage and exclusions. Every sentence earns its place; the sibling exclusions are the payload, not filler.

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 two-integer pure function with a fully documented schema, the description covers purpose, routing, and side-effect profile, which is sufficient to invoke it correctly. No output schema exists, but the return value (the sum) is obvious from the description.

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 100%, so the baseline is 3; the description adds value by restating the operation as 'a + b', clarifying operand roles and ordering beyond the schema's per-field descriptions. With only two self-explanatory operands, no further semantics are needed.

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 and resource ('Calculates the arithmetic sum of two integers (a + b)') and explicitly distinguishes itself from the named siblings subtract_numbers, multiply_numbers, and divide_numbers. An agent can identify exactly what this tool does and what it is not.

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?

It states when to use it ('when you need to perform addition') and explicitly lists when not to use it, naming the alternative tool for each excluded operation. This is textbook routing guidance with clear exclusions and named alternatives.

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