get_topic_snapshot

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

With no annotations, the description fully discloses behavior: subscribe-collect-unsubscribe lifecycle, clamping of count and timeout, never blocking longer than timeout, handling of connection loss, and return format including error fields. This exceeds the burden for a tool with no 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 well-structured with a header and parameter list, but it is slightly verbose in places (e.g., the return format could be prepended). However, every sentence is informative and earns its place.

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 4 parameters, no annotations, and an output schema (though not provided in input, but the description lists return fields), the description is complete. It covers all parameters, behavior, edge cases, and return structure.

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, but the description explains each parameter in detail: topic requires leading slash, count default and clamping, timeout behavior, and msg_type optionality. This adds significant meaning 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 clearly states the tool's purpose: 'Read live data from a topic: subscribe, collect up to `count` messages (or until `timeout` seconds elapse), then unsubscribe.' This uses a specific verb and resource, and distinctively separates it from siblings like list_topics, publish_message, and call_service.

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 usage guidance: 'Use more to observe a value changing over time' and explains when the tool may return empty (silent topic, misspelled, not exist). It does not explicitly compare to sibling tools, but the context is clear enough for an agent to decide when to use it.

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