nullRatio

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable behavioral detail beyond that: it performs a single scan, scans every column, returns null/non-null counts and ratios, and sorts by sparsity. These are meaningful execution traits that help an agent anticipate behavior and cost. No contradiction with annotations.

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 a single, dense sentence that front-loads the core purpose, then specifies the output, then gives the routing alternative. There is zero fluff; every clause earns its place. It is highly efficient and easy to parse.

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 the tool's simplicity (3 parameters, 2 required), the description covers purpose, output shape (counts, ratios, sorting), scope (every column, one table), and usage routing. An output schema exists, so return details are already structured. Nothing an agent needs to correctly invoke this tool is missing.

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% (only the connection parameter has a description). The tool description does not add parameter-level semantics, but the parameter names (table, schema, connection) are self-explanatory, and the connection parameter has a useful schema description ('Call listConnections for valid names; do not guess'). The description implies that table and schema identify the target table, so the agent can infer usage. This is adequate but not enhanced beyond the schema.

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 uses a specific verb ('Find') and resource ('sparse or mostly-null fields across every column of one table'), clearly stating what the tool does. It also differentiates from a sibling by naming describeTable as the alternative when only declared nullability is needed, so an agent can distinguish it without inspecting 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?

It explicitly tells the agent when to use this tool (when actual null counts/ratios are needed) and when to use the alternative ('use describeTable when only declared nullability is needed'). This is direct routing guidance that leaves no ambiguity about selection among siblings.

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