check_query_scan_amount

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

With no annotations provided, the description effectively discloses the tool's behavior: it performs a dry-run without executing, meaning it is read-only and has no side effects. It also mentions the default behavior for the project_id parameter. However, it does not specify return format (e.g., bytes, MB) or other behavioral traits like error handling or quotas.

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 very concise: two sentences for the main purpose plus a bullet list for parameters. Every sentence is informative, no fluff or repetition. The structure clearly front-loads the key action and then details parameters.

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 simple tool with only two parameters and no output schema, the description covers essential information: what it does, parameters, and default behavior. However, it lacks details about the return value (e.g., whether the scan amount is in bytes or other units) and does not address potential error scenarios. Minor completeness gap.

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 provides clear, meaningful descriptions for both parameters: 'sql: The SQL query to check' and 'project_id: Optional project ID to use for the query (defaults to first configured project)'. This adds significant value beyond the schema types and defaults.

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 clearly states the tool's function: 'Check the scan amount of a BigQuery SQL query using dry-run without executing it.' It specifies the verb (check), resource (scan amount of a BigQuery SQL query), and method (dry-run). This distinguishes it from sibling tools like execute_query which actually runs queries.

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 implies usage for estimating data scanned before execution, but it does not explicitly state when to use this tool versus alternatives. There is no mention of when not to use it or reference to sibling tools like execute_query for running the query. The guidance is adequate but not explicit.

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