list_databases

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

With no annotations provided, the description carries full burden and does well by disclosing key behaviors: it queries sys.databases, excludes system databases by default, respects a blocklist, and returns structured data. It doesn't mention authentication needs, rate limits, or whether it's read-only (though implied), leaving some gaps.

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 well-structured and front-loaded with the core purpose, followed by implementation details, parameter explanation, and return format. Every sentence adds value without redundancy, making it efficient and easy to parse.

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 the tool's low complexity (1 parameter), no annotations, and the presence of an output schema that documents return values, the description is complete. It covers purpose, behavior, parameter semantics, and output structure adequately without needing to explain return values in detail.

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?

The description adds significant meaning beyond the input schema, which has 0% description coverage. It explains the include_system parameter's effect ('include system databases in the list'), compensating fully for the schema's lack of documentation and providing clear usage context.

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 specific action ('List all available databases') and resource ('on the SQL Server'), distinguishing it from siblings like list_tables or list_stored_procs. It provides precise scope details about system databases and blocklist exclusions.

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 context by specifying what databases are excluded and when to use the include_system parameter. However, it doesn't explicitly state when to choose this tool over alternatives like list_connections or describe_table, nor does it mention prerequisites like requiring an active connection.

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