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

With no annotations, the description carries the full burden and does well: it discloses that these are Miles' personal estimates, not market prices, that they must be attributed, and that the tool intentionally avoids other card-related data. This is meaningful behavioral context.

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 deliver the core definition, usage pattern, and important caveats with no wasted words. The essential information is front-loaded.

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 read-only estimation tool with two optional parameters, the description fully covers what the tool returns, how to invoke it, important attribution caveats, and what it deliberately excludes.

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 explaining the no-arguments list behavior and emphasizing exact program spelling from that list, which supplements the loose matching note in the schema.

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 ('estimate'), resource ('loyalty point's value in cents'), and optional multiplication by balance. It also differentiates from card-fact and transfer tools by explicitly excluding earning rates, welcome offers, transfer ratios, and bonus sizes.

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?

Clear guidance is provided: call with no arguments to list all programs and exact spellings, and omit program to list all. It also tells users what this tool is not for, though it does not explicitly name sibling tools as alternatives.

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