MCP PostgreSQL Operations

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 does well by explaining version-dependent behavior (PostgreSQL 16+ vs 12-15), what data is returned (buffer cache efficiency, I/O timing, patterns), and prohibited actions. However, it doesn't mention potential side effects, rate limits, or authentication requirements.

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 uses clear section headers ([Tool Purpose], [Exact Functionality], etc.) that make it scannable and front-loaded. While comprehensive, some sections could be more concise; every sentence earns its place by adding specific guidance.

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 complexity of version-dependent behavior, 2 parameters with no schema descriptions, and the presence of an output schema, the description is remarkably complete. It covers purpose, functionality, usage guidelines, prohibitions, parameters, and return values - providing everything needed for proper tool selection and invocation.

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?

With 0% schema description coverage, the description compensates by explaining both parameters in the Args section: 'limit' with its range and default, and 'database_name' as optional target. This adds meaningful context beyond the bare schema, though it could elaborate on database_name implications.

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 explicitly states the tool's purpose as 'Analyze comprehensive I/O statistics across all database operations with version compatibility' in the [Tool Purpose] section. It clearly distinguishes from siblings like get_index_io_stats and get_table_io_stats by specifying it covers 'all database operations' rather than specific components.

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 includes both [Required Use Cases] with specific trigger phrases and scenarios, and [Strictly Prohibited Use Cases] that explicitly state when NOT to use this tool. This provides comprehensive guidance on when to select this tool versus alternatives.

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