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

The annotations only provide idempotentHint=true; the description adds a concrete behavioral fact by stating it validates ownership and does not reserve credits. This goes beyond the annotations, though validation failure modes and any other side effects are not covered.

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, front-loaded with the main purpose and no filler. The non-reservation caveat is concise and behaviorally important.

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 tool with five parameters and no output schema, the description gives useful workflow and side-effect context, but leaves parameter semantics and return details largely to inference. It is adequate for a lightweight preflight action, but not fully complete.

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 only 20%, so the description must compensate, but it does not. It mentions an 'owned PDF' but never maps this to file_id, and it says nothing about target_language, pages, output_formats, or source_language.

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 names a specific action pair (validate/estimate), a precise resource (an owned PDF), and the purpose (page credits before approval). It also clearly distinguishes itself from create_translation by stating it does not reserve credits.

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 gives a clear workflow position: use this before asking the user to approve translation. 'Does not reserve credits' also signals this is a no-commitment estimation step, though it does not explicitly name create_translation as the alternative for actually creating the translation.

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