MCP PostgreSQL Server

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. 'Get table structure' implies a read-only operation, but it doesn't specify whether this requires specific permissions, what the output format is (e.g., JSON, table), or if there are any limitations (e.g., rate limits, error handling). The description is too brief to adequately inform the agent about behavioral traits beyond the basic action.

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 extremely concise with just three words, making it front-loaded and efficient. However, it borders on under-specification given the tool's purpose and lack of annotations, which slightly reduces its effectiveness. Every word earns its place, but more detail could improve clarity without sacrificing brevity.

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 complexity (a read operation with 2 parameters), no annotations, and no output schema, the description is incomplete. It fails to explain what 'table structure' includes (e.g., columns, data types, indexes), the return format, or any behavioral aspects like error cases. This leaves significant gaps for the agent to understand how to use the tool effectively.

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 input schema has 100% description coverage, clearly documenting both parameters ('schema' and 'table') with their types and requirements. The description adds no additional semantic context beyond implying that 'table' is the primary identifier. Since the schema does the heavy lifting, a baseline score of 3 is appropriate, as the description doesn't compensate but also doesn't detract.

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 'Get table structure' clearly states the action (get) and target (table structure), which is better than a tautology. However, it's somewhat vague about what 'structure' entails (e.g., columns, types, constraints) and doesn't distinguish it from sibling tools like 'list_tables' or 'query', which might also provide structural information.

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., needing a database connection via 'connect_db'), differentiate it from 'list_tables' (which lists table names) or 'query' (which might retrieve data), or specify use cases like schema exploration. This leaves the agent with minimal context for selection.

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