mysql_variables

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

With no annotations, the description carries the full burden of behavioral disclosure. It does disclose that the result is curated and conditionally includes the query cache 'if present,' which is useful context. Still, it does not state that this is a read-only operation, what filtering criteria apply, or how the tool behaves if variables are unavailable.

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 sentence conveys the command, the selection strategy, and the categories included, with no filler or redundancy. The phrase 'if present' adds precision without extra length.

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 zero-parameter, read-oriented diagnostic tool with an output schema, the description is nearly complete: it tells the agent what the tool returns and what is included. It could be slightly stronger by naming the exact variables or stating the read-only nature, but nothing essential is missing for calling it correctly.

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 tool has zero parameters and the schema coverage is 100%, so there is no parameter information the description needs to add. Per the baseline for parameterless tools, this is adequate.

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 identifies a specific resource (SHOW GLOBAL VARIABLES) with a clear verb-frame ('Curated') and names the exact categories it covers (buffer pool, connections, slow log, query cache). This makes the tool's purpose immediately recognizable and distinguishes it from status-only siblings like mysql_global_status.

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 the tool should be used when the agent wants a focused view of server variables, thanks to 'Curated SHOW GLOBAL VARIABLES.' However, it does not explicitly state when to prefer it over closely related siblings such as mysql_global_status or mysql_status_delta, nor does it provide any exclusion conditions.

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