explain_query

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

With no annotations, the description carries the full burden, and it does disclose one non-obvious behavioral trait: deployments lacking EXPLAIN support return the server's error rather than failing silently. However, it says nothing about the return shape (text plan vs rows), read-only safety, or whether the statement is actually executed, which matters for a tool taking arbitrary SQL.

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?

Two compact sentences with the core purpose front-loaded and the caveat trailing; no filler. Slightly terse given the missing return-format detail, but nothing is wasted.

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?

There is no output schema, so the description should explain what comes back; it gestures at this (a plan, or the server's error) but doesn't describe the plan's format or whether the query runs. Adequate but with a clear gap for a single-param diagnostic tool.

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% and there is only one parameter ('sql', documented as 'The statement to explain'), so the schema already does the work. The description adds only the EXPLAIN framing via '<sql>', which is not meaningfully more than the schema provides.

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?

States a specific verb (show the plan) and resource (a statement), and the parenthetical '(EXPLAIN <sql>)' pins down the exact SQL operation being wrapped. It doesn't explicitly differentiate itself from the sibling execute_sql, but an agent can infer the distinction from 'plan' vs execution.

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 the tool is relevant (diagnosing a statement's plan) and warns about the unsupported-EXPLAIN case, but never says when to prefer it over execute_sql or list/describe siblings. Usage is only implied, not spelled out.

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