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

With no annotations, the description carries the full burden and does disclose meaningful traits: deterministic arithmetic, no external API, and a paid path ("$0.001 USDC on Base via x402"). That payment/cost disclosure is genuinely useful context an agent cannot get from the schema, though it omits error behavior for invalid unit pairings.

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 tight sentences with the core purpose front-loaded and the cost/mechanism detail deferred to the end. No filler, though the pricing sentence is arguably secondary to conversion semantics.

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 3-param tool with no output schema and no annotations, the description covers purpose, determinism, and cost but leaves the return shape (a single number?), cross-category error handling, and temperature conversion behavior unexplained.

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 0%, so the description must compensate. It names the supported dimensions that map onto the two enum parameters, adding some meaning, but never states that 'from' and 'to' must belong to the same dimension, nor addresses the affine nature of temperature (C/F/K) conversions.

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?

States a specific verb (convert) and resource (numeric value between units) plus the supported dimensions (length, mass, time, temperature, data sizes). This implicitly distinguishes it from siblings like timezone-convert, though it never names or contrasts against them.

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 is only implied: the category list and 'no external API' hint at when it applies, but there is no explicit when-to-use, when-not-to-use, or routing to alternatives such as timezone-convert for date/time-zone work.

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