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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is covered. The description adds valuable behavioral context by detailing the types of optimizations it performs (sequential scans, missing indexes, etc.) and that it suggests index DDL. This goes beyond the annotations without contradicting them.

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 two sentences, front-loaded with the primary purpose, followed by supporting details. Every sentence earns its place with no redundancy or fluff. It efficiently conveys main function, typical findings, and output.

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 (two params, output schema, read-only), the description covers the core behavior, what it identifies, and output. The output schema likely documents return values, so no need to repeat. Minor gaps include not explicitly stating that it does not execute the query, but the word 'Suggest' implies this. It lacks explicit mentions of permissions or limitations, but annotations cover safety.

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%, with both parameters fully described: 'query' as 'SQL query to optimize' and 'connection' with detailed guidance on resolving names. The tool description itself adds no extra parameter semantics beyond what the schema already provides, so baseline 3 is appropriate.

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 function: 'Suggest a rewritten, optimized version of a SQL query with explanations.' It specifies the verb (suggest), resource (SQL query), and adds specific details about what it identifies (sequential scans, missing indexes, sort spills, join inefficiencies) and what it provides (index DDL). This distinguishes it from siblings like explain_query and query_sql.

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 for optimizing SQL queries but provides no explicit when-to-use or when-not-to-use guidance, nor does it mention alternatives. The mention of identifying specific query issues suggests a use case, but it fails to state exclusions or direct users to other tools like explain_query for execution plans.

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