PostgreSQL MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It describes what the tool does ('Get an overview') but lacks details on behavioral traits such as whether it's read-only (implied but not stated), performance characteristics (e.g., if it's slow for large schemas), error handling, or output format. For a tool with zero annotation coverage, this is a significant gap, though it's not misleading—just insufficient.

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 that efficiently conveys the tool's purpose without any wasted words. It's front-loaded with the main action ('Get an overview') and specifies the scope ('database schema including tables and their relationships'), making it easy to understand at a glance. Every part of the sentence earns its place, achieving optimal conciseness.

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 (simple read operation with no parameters) and the lack of annotations and output schema, the description is adequate but not complete. It explains what the tool does but doesn't cover behavioral aspects like output format or potential limitations. For a tool in this context, it meets minimum viability but could benefit from more detail to fully guide an agent, scoring a 3.

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% (since there are no parameters to describe). The description doesn't need to add parameter semantics, so it meets the baseline of 4 for tools with no parameters. It appropriately focuses on the tool's purpose without unnecessary parameter details.

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 tool's purpose with a specific verb ('Get') and resource ('database schema'), specifying it includes 'tables and their relationships'. It distinguishes from siblings like 'list_tables' (which might just list names) and 'describe_table' (which focuses on a single table). However, it doesn't explicitly differentiate from potential alternatives like 'execute_query' for schema queries, keeping it at 4 rather than 5.

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 when needing an overview of the database structure, which suggests context for database exploration or query planning. However, it doesn't explicitly state when to use this tool versus alternatives like 'list_tables' (for just table names) or 'describe_table' (for detailed info on a specific table), nor does it mention prerequisites such as needing a connected database first. This leaves some ambiguity, scoring a 3 for implied but incomplete guidance.

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