Query topic messages with SQL

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description only needs to add context beyond safety. It adds the single-topic scope and the DuckDB engine, but does not discuss query limits, errors, or authorization; without the output schema, the 'structured dictionaries' line would be the only return-value insight.

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 sentences with the action first, output second, and usage guidance third; no filler. It is appropriately scaled for a moderately complex tool, though it could add a brief parameter note without becoming verbose.

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?

The core behavior and primary use case are covered, and the output schema plus annotations handle return values and safety. Still, for a tool with six parameters and user-supplied SQL, the description omits time-range semantics, args, and any boundary conditions such as cross-topic queries being unsupported.

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?

With schema description coverage at 0%, the description carries the parameter-explanation burden. It clarifies path (data source), topic (single topic), and sql_statement (DuckDB SQL capable of filtering/aggregation/downsampling), but leaves args, start_seconds, and end_seconds entirely unexplained.

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 opens with a specific action ('Run a DuckDB SQL query') and a bounded resource ('messages from a single topic in a data source'), clearly distinguishing it from sibling describe/run/export tools. It also states the intended result ('structured dictionaries').

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 says to use this tool for answering questions about message data with filtering, aggregation, and downsampling, which gives clear application context. It does not, however, name alternatives or exclusion cases, such as when to use export_for_plotjuggler or run_pipeline instead.

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