explain_query

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

With no annotations provided, the description carries the full burden. It discloses that the tool provides execution plans and cost estimates, and hints at performance implications ('Takes longer but provides more accurate information' for the analyze parameter). However, it doesn't cover other behavioral traits like permissions needed, rate limits, or what the output format looks like (no output schema exists).

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, well-structured sentence that front-loads the core purpose and efficiently adds key details. Every phrase earns its place by clarifying scope and output without redundancy or unnecessary elaboration.

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 moderate complexity (3 parameters, no output schema, no annotations), the description is adequate but has gaps. It covers the purpose and hints at behavior but doesn't fully address usage scenarios, output format, or integration with sibling tools. Without annotations or output schema, more context on what the explanation includes would be helpful.

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 parameters thoroughly. The description adds minimal value beyond the schema by mentioning 'detailed cost estimates' which relates to the sql parameter's purpose. With high schema coverage, the baseline is 3, but the description slightly enhances understanding of the tool's output context.

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 specific action ('explains the execution plan'), identifies the resource ('SQL query'), and distinguishes it from siblings like execute_sql (which runs queries) and analyze_query_indexes (which focuses on indexes). The phrase 'showing how the database will execute it and provides detailed cost estimates' adds precise scope.

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 context for query optimization and performance analysis, which differentiates it from execute_sql (for running queries) and get_top_queries (for monitoring). However, it lacks explicit guidance on when to choose this tool over alternatives like analyze_query_indexes or when not to use it (e.g., for simple queries).

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