unused_indexes

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

With no annotations, the description carries the burden and does well by revealing the data source, the restart-reset behavior, and the fact that only zero-I/O secondary indexes are returned. This goes beyond the tool name and adds important context. It does not detail the output format, but the 'drop candidates' hint implies a list of index identifiers.

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 very concise, front-loaded with the key purpose, and uses a short second line for the important caveat. The parameter documentation is compact and clear. Every sentence adds value; no fluff.

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 read-only tool with one optional parameter, the description covers purpose, data source caveat, and parameter meaning. It lacks an explicit statement of the return value (e.g., list of index names), but the tool is simple and the purpose is clear. Overall it is complete enough for reliable invocation.

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 0%, so the description must explain the parameter. It does: 'target: Target name from config; omit for the default.' This is sufficient for an optional config-like parameter, adding meaning beyond the bare JSON schema type.

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 identifies the tool as listing secondary indexes with zero I/O events since restart, and explicitly frames them as drop candidates. This distinguishes it from sibling tools like redundant_indexes or index_stats by the 'unused' criterion and drop-candidate purpose. The verb is implied by '[READ]' and the noun phrase, but not strictly stated as 'list'.

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 gives clear context that the data comes from performance_schema counters that reset on restart, and advises confirming over a full business cycle. This helps the agent decide when results are meaningful. It does not explicitly name alternative tools to use instead, but the caveat forms practical usage guidance.

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