Describe a data source

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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds transparency by explicitly stating what is included (summary, metadata, topics) and excluded (messages, detailed definitions), which helps set expectations beyond the schema. It does not add unnecessary detail, and no contradictions with annotations exist.

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 exceptionally concise: two sentences, front-loaded with the core purpose, and then a clear list of inclusions and exclusions. Every sentence earns its place with no redundant or tangential information.

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 existence of an output schema and the moderate complexity (one required parameter, optional args), the description covers the key aspects: what it does, what it returns, and what it excludes. It could be slightly more complete by explaining the purpose of 'args' or providing an example, but it is sufficient to differentiate from siblings and understand basic usage.

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?

The input schema has 0% description coverage, and the tool description does not explain the meaning of the 'path' parameter or the optional 'args'. It only implies that 'path' identifies a data source, which is inferred from the tool name. The description fails to provide adequate semantics for parameters, leaving the agent to guess about path format or additional arguments.

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 clearly states the tool's function: 'Summarize a data source without returning its messages.' It specifies the resource (data source) and the action (summarize), and distinguishes it from sibling tools like query_messages and describe_topic by explicitly excluding messages and detailed topic definitions.

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 provides clear context about what the tool returns and excludes, implying when to use it (when you need a high-level summary rather than messages). However, it does not explicitly name alternative tools or provide explicit 'when not to use' guidance, so it stops short of a 5.

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