Subscribe to live topic messages

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

Beyond the annotations (destructiveHint=true, readOnlyHint=false), the description discloses that it runs in the background, persists messages locally, may continuously write/upload artifacts via an optional pipeline, and that overwrite=True clears existing topic buffers. These are meaningful behavioral details the agent would not otherwise know.

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 compact and front-loaded with the core action and return value. Every sentence adds useful context: sequencing, pipeline caveat, overwrite behavior, lifecycle, and an exclusion. No filler or redundancy.

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 and the presence of an output schema, the description covers the essential operational context: background execution, local persistence, returned sink directory, optional artifact-writing pipeline, destructive overwrite behavior, and how to stop the subscription. Nothing critical is missing for an agent to invoke it correctly.

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 does explain type_ (mqtt, ros1.bridge, ros2.bridge), overwrite (clears buffers), and pipeline (continuous processing, may write/upload). However, it leaves host, port, topics, and particularly the opaque args object semantically unexplained, though some are inferable from their names.

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 states a specific verb ('Start a background subscription'), the resource types (mqtt, ros1.bridge, ros2.bridge), and the purpose (persist messages locally and return a sink directory). It clearly differentiates from siblings by saying to use list_live_topics first, to stop with unsubscribe_live_topics, and that it is not for inspecting an existing file.

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 gives explicit sequencing ('Use list_live_topics first'), the lifecycle counterpart ('Stop it with unsubscribe_live_topics'), and an exclusion ('Not for inspecting an existing file'). This is strong guidance on when and how to use the tool relative to alternatives.

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