list_extensions

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states what the tool does but doesn't describe how it behaves: no information on output format (e.g., list structure, fields returned), pagination, error conditions, or whether it requires specific permissions. This leaves significant gaps for an agent to understand the tool's operation.

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 a single, clear sentence with zero wasted words. It's front-loaded with the core action and resource, making it immediately scannable and efficient. Every word earns its place by specifying the exact scope ('all installed PostgreSQL extensions').

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 simplicity (0 parameters) but lack of annotations and output schema, the description is incomplete. It doesn't explain what the output looks like (e.g., array of extension names with versions), which is critical for a list operation. For a read-only tool with no structured output documentation, more behavioral context is needed.

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 tool has 0 parameters, and schema description coverage is 100% (though empty). The description appropriately doesn't discuss parameters since none exist. It could theoretically mention that no inputs are required, but this is adequately covered by the schema, so a baseline 4 is appropriate.

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 verb ('Lists') and resource ('all installed PostgreSQL extensions in the database'), making the purpose immediately understandable. It doesn't explicitly differentiate from sibling tools like 'list_tables' or 'list_auth_users', but the specificity of 'PostgreSQL extensions' provides inherent distinction.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., database connection), use cases (e.g., checking available extensions before installation), or how it differs from other list tools like 'list_tables' or 'list_auth_users'.

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