mysql_legacy_list_databases

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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the description doesn't need to repeat those. It adds value by disclosing the default hiding of system databases and the override via parameter or environment variable (MYSQL_LEGACY_HIDE_SYSTEM_DATABASES=false). This is behavioral context beyond the schema. It does not contradict any annotation.

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-loads the primary action, and includes all essential details (behavior, override, next step, exclusions) with zero waste. Every sentence earns its place.

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?

For a simple list tool with one optional parameter and no output schema, the description is complete: it states the action, the default behavior, the override, what it doesn't do, and the recommended follow-up. Nothing an agent needs to call it correctly is missing.

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 parameter is fully documented in the schema. The tool description adds the default behavior (system databases hidden unless include_system_databases=true or env var set) which is not explicitly in the schema, clarifying the parameter's effect in context. This enriches the parameter semantics beyond 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 and resource ('Lists database names via SHOW DATABASES') and explicitly differentiates from siblings by noting it does not list tables or columns. It also points to the next step in the workflow (mysql_legacy_list_tables), making its purpose unambiguous.

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 when to use it (when you need database names) and gives a concrete next step ('Then pass a name to mysql_legacy_list_tables'), which is useful guidance. It also clarifies that it does not cover tables/columns, indirectly steering the agent toward alternatives. However, it doesn't explicitly state when not to use it or name alternative tools for other tasks, though the sibling context and the hint are sufficient.

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