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

Annotations already declare readOnlyHint and destructiveHint, so the safety profile is covered; the description still adds real value by noting that writes and DDL are rejected, that SQL is safety-checked, and that the tool connects either directly or through the in-VPC/VNet proxy. It stops short of describing the return shape, pagination, or row limits.

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 short sentences, front-loaded with the core action and the read-only constraint, with no filler or repetition. Every sentence carries a distinct fact.

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 tool with no output schema, two undocumented required parameters, and ambiguous siblings, the description leaves key gaps: the return format is unexplained, parameter formats are absent, and the distinction from nexusai_managed_db_execute is missing. Annotations carry safety, but the rest of the burden is unmet.

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 only 33% (just 'params'), and the description adds nothing about any parameter: it never explains what 'sql' accepts, what 'managedDatabaseId' identifies, or how positional 'params' are bound to placeholders. With this coverage gap, the description should compensate and does not.

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 ('Run a read-only SELECT against a managed database') and clarifies the scope (no writes/DDL). However, it never distinguishes this tool from the closely named sibling nexusai_managed_db_execute, so an agent cannot tell which one to pick without inspecting both schemas.

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?

There is no when-to-use guidance and no mention of alternatives, despite several overlapping siblings (nexusai_managed_db_execute, nexusai_db_query_execute, nexusai_db_query_preview, nexusai_db_inspect_schema). The connection-mode note (public vs private proxy) is informational but does not tell the agent when to choose this tool over another.

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