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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description contributes real behavioral context by disclosing the 1024-vs-1000 base rule and the fact that IEC KiB/MiB are always 1024, which is not fully stated in the schema. It says nothing about rounding or output precision, so it is additive but not rich.

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?

Two short sentences with the unit domain front-loaded and the convention rule second; no filler, no repetition, and the most decision-relevant fact (binary is the default) is placed where it will be read.

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?

With an output schema present, the description needn't explain return values, and annotations cover the safety profile. It adequately covers units and the base convention for a simple read-only converter; the only mild gap is precision/rounding behavior when converting between exact and non-exact bases.

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 all four parameters (value, from_unit, to_unit, convention) are already documented with examples and a default. The description restates the binary/decimal convention in compressed form and adds the IEC caveat, but adds no syntax or format guidance beyond the schema; baseline 3 applies.

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 uses a clear verb (Convert) plus the specific resource domain (Byte/KB/MB/GB/TB), which is unambiguous. It does not, however, name or exclude the near-neighbor tools such as calculator_convert, calculator_base_convert, or calculator_binary, so an agent must infer that this is the data-storage-specific converter.

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?

Usage context is only implied: the unit list signals 'use me for data storage sizes,' and the convention sentence implicitly tells the agent to leave convention at default unless SI decimal is wanted. There is no explicit when-to-use versus calculator_convert or calculator_base_convert, and no stated preconditions.

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