mysql_replica_status

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

With no annotations provided, the description carries the full burden. It discloses the SQL version differences (SHOW REPLICA STATUS vs SHOW SLAVE STATUS), what is returned (replica lag, thread state, errors), and the normal result for non-replicas. It implies a read-only operation without explicitly stating so, but that's a minor omission.

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?

Three concise sentences, each earning its place: the first lists the core output, the second notes implementation details and version handling, and the third clarifies the normal empty result. No waste, front-loaded with purpose.

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 an output schema exists, the description need not enumerate return fields. It explains the purpose, the version-specific SQL, and the typical result on non-replicas, covering everything an agent needs to decide when to call it and interpret the response.

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, so the schema coverage is trivially 100%. The description correctly adds no parameter information since there are none. Baseline for 0 params is 4.

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 the specific resource (replica status) and the key data it returns (lag, thread state, errors). It clearly distinguishes itself from siblings by noting it returns replication channel metadata only, not binlog row contents, and by defining the normal empty result on standalone/primary servers.

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 clarifies when this tool is relevant by stating it only covers replication channel metadata and that empty rows are normal on a standalone/primary server, effectively guiding an agent to avoid using it when not monitoring a replica. It doesn't explicitly name alternative tools, but the context is sufficient.

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