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

With no annotations, the description must disclose behavioral traits. It fails to clarify that the tool is a pure function with no side effects, and more critically, it contradicts the input schema by referencing markup % and margin % inputs that do not exist in the schema. This misalignment severely undermines transparency.

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 brief and well-structured: three sentences covering purpose, usage, and a pointer to related tools. It is not verbose, but the misalignment with the schema reduces its effectiveness.

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 input schema mismatch and missing explanation of the actual parameters, the description is fundamentally incomplete. It fails to accurately describe what inputs the tool accepts, making it unreliable for an AI agent to invoke correctly.

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?

Despite 100% schema coverage, the description adds misleading information: it claims inputs include 'either markup % or margin %', but the schema only contains 'cost' and 'selling_price'. This misdirects the AI, negating any value from the description and creating confusion.

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 'Convert between markup and margin (often confused)', providing a specific verb and resource. It also identifies use cases ('pricing decisions or COGS reporting') and distinguishes from sibling tools by focusing on a specific conversion.

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 gives clear context on when to use ('pricing decisions or COGS reporting') and points to an alternative ('See list_bundles for related finance-universal calculators'). However, it does not explicitly state when not to use this tool.

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