dry_run

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

With no annotations, the description carries the behavioral disclosure burden. It clearly states the tool does not execute the statement and that it reports both allowability and the reason for denial. This covers the most critical behavioral traits, though it omits details like permissions or failure modes.

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?

One tightly constructed sentence that front-loads the action, states the key non-execution behavior, and names the compared sibling. Every word earns its place with no redundancy.

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?

The tool is simple with a single required parameter and an output schema, so the description does not need to explain return values. Purpose, behavior, and relationship to run_query are all covered sufficiently for correct selection and 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?

Schema coverage is 0%, so the description must compensate. It adds the meaningful constraint that the input is a single statement, but it does not describe sql syntax, format, or dialect. The parameter name 'sql' is self-explanatory, but the description adds only marginal value beyond it.

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 verb ('estimate') and resource ('bytes scanned for one statement'), and explicitly contrasts itself with run_query. This makes the tool's purpose unmistakable and clearly distinguishes it from the sibling tools.

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 phrase 'without running it' and 'whether run_query would allow it' clearly implies the tool is a preflight check for run_query. It gives a clear usage context, though it does not explicitly state exclusions or when to prefer alternatives.

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