run_readonly_query

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

Discloses read-only nature, security boundary via role limitation, and enablement requirement. With no annotations, description carries full burden and does well, though rate limits or error handling omitted.

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 sentences plus a one-line parameter doc, front-loaded with purpose and constraints. Every sentence adds value.

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?

Given one parameter and output schema present, description adequately covers purpose, constraints, enablement, and parameter semantics. Output schema details not needed in description.

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 has 0% coverage but description clarifies 'sql' must be a 'single read-only SELECT statement', adding constraint beyond the schema. Compensates for missing schema description.

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?

States 'run an arbitrary read-only SELECT query against Snowflake' with specific purpose 'for cost or performance investigation beyond the built-in tools', clearly distinguishing from 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?

Indicates it is disabled by default and must be explicitly enabled, only accepts SELECT/WITH...SELECT, and advises a read-only role. Could explicitly mention alternatives but implies siblings are for common investigations.

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