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

Annotations cover read-only and open-world safety, but the description adds genuinely useful non-schema context: the SQLite execution backend, the 100,000-row ceiling, and a per-call cost of $0.003 USDC (x402). The phrase 'run any SELECT' also implicitly confirms write statements are not accepted, consistent with readOnlyHint=true. Error/timeout behavior is not described.

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 dense sentences, front-loaded with the action and resource, then capability list, limits and price. Every clause carries information; no filler.

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 three-parameter, no-output-schema tool, the description covers the capability envelope, size limit and cost. It does not indicate the shape of the returned result set (rows/columns/format) or failure modes, which is a modest gap given there is no output schema to fall back on.

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 100% and each of the three parameters already carries a description, so the schema does the heavy lifting. The description restates the data/tables relationship and the SELECT-only constraint on query but adds no format or syntax detail beyond what the schema says.

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 ('Run') and resource ('SQL on your data') and enumerates the supported query surface (SELECT, GROUP BY, JOIN, window functions, CTEs), which tells an agent exactly what it can accomplish. It does not explicitly distinguish itself from the sibling sql_generate (or db/data_run), leaving the run-vs-generate boundary to inference from the names.

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?

Usage is implied: load JSON/CSV/named tables, then run a SELECT. There is no explicit 'use this when…, use sql_generate when…' guidance and no prerequisites or exclusions, so the agent must infer the routing from context.

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