coin_change

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 says nothing about determinism, side effects, error behavior (e.g., unreachable amount), or the shape/format of the returned result, even though it promises two distinct outputs. For a computation tool with zero annotation coverage this is a real 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?

A single efficient sentence with the two operations front-loaded and no filler. It is appropriately sized, though inherently thin given what it omits.

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 two-parameter algorithmic tool with no output schema, stating both outputs is helpful and covers the essentials. It still leaves return format/conventions (order-independence of combinations, behavior on impossible amounts) unspecified.

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% (both 'coins' and 'amount' are documented, including the 1,000,000 cap), so the baseline is 3. The description does not add anything beyond the schema, such as whether denomination order or duplicates matter.

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 names the resource (coin denominations / target amount) and the two specific computations (minimum coins, count of distinct combinations), which is more than a tautology. It does not, however, differentiate itself from algorithmic siblings like knapsack_solve or combination_calc, leaving the agent to infer scope.

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 statement of when to use this tool versus alternatives, no prerequisites, and no mention of edge cases (e.g., impossible amounts, duplicate denominations). Usage is only implied by the tool name.

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