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

Annotations already declare readOnlyHint=true, and the description aligns with that. It adds valuable context by noting that row counts and sizes are approximate, which prevents the agent from treating them as precise figures. No behavioral contradictions are present.

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?

A single, efficiently structured sentence covers scope, primary behavior, conditional behavior, and output specifics without redundancy. The key limitation is front-loaded.

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 output schema and read-only annotation, the description is largely complete for invoking the tool correctly. It covers both input modes and notes the approximate nature of table metrics. It could be slightly fuller by explicitly steering agents away from using this tool for executing queries, but that gap is minor.

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 input schema already documents both parameters, so the baseline is 3. The description adds meaning by explaining that supplying the 'table' parameter changes the output from table-level listing to detailed column, index, and CREATE TABLE information, which is not fully evident from the schema alone.

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 states a specific verb ('lists'), a clear resource ('the site's database'), and the conditional behavior for the optional table parameter. It clearly distinguishes this structural introspection tool from data-manipulation siblings like query_database and execute_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 communicates when it applies ('PHP + MySQL plans') and the two modes of use. However, it does not explicitly contrast this tool with alternatives such as query_database or execute_sql, so the agent must infer when to choose this over those siblings.

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