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

The description adds substantial behavioral detail beyond the annotations: pricing at $0.01 per call, payment via x402 USDC or a card key, first 25 calls free, failed calls free, and that repeated calls are charged because the operation is not idempotent. It also confirms the tool reads or computes only and changes nothing, which aligns with the readOnlyHint and destructiveHint=false annotations.

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 front-loaded with the core purpose, then moves immediately into language-code guidance and an example before covering pricing and side-effect behavior. Each sentence adds useful information for invocation or cost awareness, with no significant filler.

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 three-parameter translation tool with fully covered schema descriptions and clear annotations, the description is complete enough to call correctly. It covers purpose, parameter format, cost model, free tier, and confirms that the operation changes nothing, leaving no critical gaps for an agent.

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 the parameters are already well documented in the schema. The description adds some helpful examples of target ISO codes and a full example call, but most of its parameter guidance repeats what the schema already provides, making the baseline 3 appropriate.

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 and resource: translate text between about 100 languages using Meta's M2M100 model. It also gives concrete usage context (localising messages and documents) and an example, so an agent can distinguish it from sibling AI tools like ai_rewrite or ai_summarize_text.

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?

It clearly says to use the tool for localising messages and documents, and explains that the target language should be an ISO code while the source language is optional. It does not explicitly contrast when to choose this over related siblings, but the usage context is clear enough for correct selection.

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