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

The readOnlyHint annotation already signals a safe, non-mutating operation. The description adds meaningful behavioral context by stating this is a free dry-run that estimates rows, sample resolvability, output bytes, errors, and charge units without executing the conversion. No contradiction with 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?

A single, dense sentence that front-loads the core value proposition ('Free dry-run quote') and then lists the estimated outputs. Every word earns its place; there is no fluff or redundant restating of the tool name.

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 read-only estimation tool, the description covers the essential inputs (uploaded or pasted data) and outputs (rows, resolvability, bytes, errors, charge units). Given the absence of an output schema, this is helpful. The complex schema still carries most parameter-level context, but the description is complete enough for tool selection and initial invocation.

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?

With 13 parameters and only 62% schema description coverage, the description needed to compensate, but it adds little parameter-specific meaning. It references 'uploaded or pasted user data' and 'sample resolvability,' but does not clarify the anyOf input modes, geography_binding, or from_system semantics. Most parameter understanding must come from the schema.

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 specific verb ('Estimates') and resource ('conversion job'), and clearly frames it as a free dry-run quote rather than actual conversion. The phrase 'before execution' distinguishes it from create_conversion_job, and the listed estimate outputs clarify what the tool produces.

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 communicates the key usage context: use this tool to get a pre-execution estimate for uploaded or pasted user data conversion. It implies this is the preview step before create_conversion_job, though it does not explicitly name alternative tools or state when not to use it.

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