subscribe_once

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

No annotations are provided, so the description carries full burden. It mentions the tool subscribes and returns the first message, but does not disclose critical behavioral traits such as timeout behavior, error handling (e.g., if no message arrives), permission requirements, or rate limits. The example adds some context but leaves operational details unclear.

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 appropriately sized with two sentences: a clear purpose statement followed by a concise example. It is front-loaded with the core functionality, and every sentence adds value without redundancy or unnecessary elaboration.

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 complexity (interactive subscription with ROS), lack of annotations, no output schema, and low schema coverage, the description is incomplete. It fails to explain return values, error conditions, or integration context (e.g., ROS environment requirements), making it inadequate for safe and effective use by an AI agent.

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 0%, so the description must compensate. It adds meaning by explaining that 'topic' is the ROS topic to subscribe to and 'msg_type' specifies the message type, as shown in the example. However, it does not detail parameter formats (e.g., topic naming conventions) or default behaviors, leaving gaps in documentation.

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 specific action ('Subscribe to a ROS topic and return the first message received') with the exact resource (ROS topic). It distinguishes from sibling tools like 'subscribe_for_duration' by specifying 'once' for single-message retrieval, and from 'publish_once' by focusing on subscription rather than publishing.

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 implies usage for retrieving a single message from a ROS topic, with an example showing parameter usage. However, it lacks explicit guidance on when to use this versus alternatives like 'subscribe_for_duration' for continuous listening or 'get_topics' for discovery, and does not mention prerequisites or exclusions.

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