set_regions

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

With no annotations provided, the description carries the full behavioral burden, and it delivers: it explains that the feed is not interrupted, existing vessels are retained until they age out of the 30-minute window, and over-budget selections are accepted rather than refused with the consequence of repeated drops/reconnects. This is far more than a generic mutation description.

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 front-loaded with the core purpose and then adds meaningful behavioral caveats. It is a bit discursive, especially the final 'honest answer' sentence, but every sentence contributes important operational information and nothing is wasted.

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 tool is simple in terms of parameters, the schema fully documents region_keys, and an output schema exists. The description covers key edge-case behavior thoroughly. A minor gap is that it does not clarify what happens when no open connection is available, but this is not enough to make the description inadequate.

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 already covers the single parameter region_keys with 100% coverage, including an example and a pointer to list_regions. The description adds no additional parameter semantics beyond restating the concept of 'sea areas,' so baseline 3 is appropriate.

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 leads with a specific verb and resource: 'Change which sea areas the live subscription watches.' This clearly distinguishes it from sibling read/query tools like list_regions, vessels_in_area, and vessels_watched. No ambiguity remains about the tool's function.

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 clear context: the tool modifies the live subscription's watched sea areas and applies to the open connection where possible. It doesn't explicitly name alternatives or when-not-to-use conditions, but the scope is specific enough that an agent can identify when this tool is the relevant one among the siblings.

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