MCP PostgreSQL Server

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

No annotations are provided, so the description carries full burden. It mentions the existence of a default connection and failure conditions, which adds useful behavioral context. However, it doesn't disclose other important traits like authentication requirements (implied by password parameter), potential side effects of establishing connections, or error handling behavior.

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 concise sentences with zero waste. The first states the purpose, the second provides crucial usage guidance. Every word earns its place, and the structure is front-loaded with essential information.

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 connection tool with 5 parameters and no output schema, the description provides good contextual completeness. It covers purpose and usage guidelines well. The main gap is lack of output information (what happens after connection), but given the tool's nature and absence of output schema, the description does reasonably well.

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 100%, so the schema already documents all 5 parameters thoroughly. The description doesn't add any parameter-specific information beyond what's in the schema. This meets the baseline of 3 when schema does the heavy lifting, but no extra value is provided.

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 action ('Connect to PostgreSQL database') and resource ('PostgreSQL database'), making the purpose immediately understandable. It doesn't explicitly distinguish from sibling tools like 'execute' or 'query', but the connection focus is clear enough to avoid confusion with execution or querying operations.

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 explicit usage guidance: 'Default connection exists - only use when requested or if other commands fail.' This clearly indicates when to use (when requested or after failure) and when not to use (when default connection works), helping the agent avoid unnecessary invocations.

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