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

With no annotations, the description must carry full behavioral transparency. It states the tool 'Returns final value, total contributed, total interest', which outlines output shape. However, it omits assumptions like compounding frequency (likely monthly) and edge cases (zero rate), leaving some behavioral gaps.

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 two sentences: purpose + inputs/outputs, plus a pointer to list_bundles. It is front-loaded, efficient, and contains no redundant words.

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?

Given the tool's moderate complexity, the description covers purpose, usage, inputs, outputs, and related tools. The missing detail (e.g., compounding frequency) is minor. Output schema exists but the description already adequately describes returns.

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 baseline is 3. The description lists the same four inputs but adds context like 'annual rate %' (clarifying unit). This is minor extra value beyond 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 clearly states the verb 'Compute' and the resource 'compound interest with monthly contributions (savings plan)', distinguishing it from the sibling 'calculate_compound_interest' by explicitly including monthly contributions.

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 description advises 'Use for systematic savers', giving clear context. It also references list_bundles for related calculators. However, it does not explicitly exclude when not to use or compare with other compound interest variants.

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