Preview execution plan

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds significant behavioral context by explaining the tool uses EXPLAIN PLAN, does not execute the query, and details what the plan reveals (table access methods, joins, filters). This goes beyond annotations, providing a full picture of the tool's 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?

The description is concise and well-structured: a clear purpose statement, an explanation of what EXPLAIN PLAN shows, a usage recommendation, and a clean Args section. Every sentence adds value without redundancy.

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?

The tool has no output schema, so the description should clarify the return format (e.g., string containing the plan). It states 'generate and display' but does not specify what the agent receives. While basic completeness is achieved, the missing output description is a gap for an analysis tool.

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 coverage is 100% and both parameters have descriptions in the schema. The description's Args section adds slight extra context (e.g., 'Read-only SQL (SELECT/WITH only)' for sql and 'default: []' for params), enhancing understanding. Given the high schema coverage, this is a 4.

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 generates and displays an execution plan for a SQL query without executing it, distinguishing it from sibling tools like db_query. It specifies the analysis of table access methods, join strategies, and filter predicates, leaving no ambiguity about the tool's function.

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 guidance to use this tool for understanding query performance before running expensive queries. It implies when not to use (when actual execution is needed) but does not explicitly compare to siblings like db_query. The usage context is clear, earning a 4.

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