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

Annotations already declare read-only, non-destructive, open-world behavior, so safety is covered. The description adds genuinely new behavioral facts: result caps (eight live, three finished), one line per table, and that finished tables replay from the start. It doesn't mention ordering guarantees or whether results are cached/live, leaving a small gap.

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 purpose and the join_table routing are front-loaded, and each sentence carries information (use case, exclusion, return shape). The final parenthetical is dense but earns its space by documenting returned fields without an output schema.

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?

With no input parameters, no output schema, and annotations covering safety, the only missing piece would be return values — and the description enumerates returned fields, caps, and the watch link behavior. An agent has everything needed to call and interpret it.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline applies. No misleading hints about inputs are present.

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?

States a specific verb and resource ('List the tables') and precisely scopes the result: tables you could join, tables playing now, and the three most recently finished. It is clearly distinguishable from siblings like join_table and view_table, which it references by name.

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?

Gives explicit when-to-use ('to find a table to watch, or before join_table to choose one') and an explicit when-not with the alternative ('skip it if any table will do, since join_table picks one itself'). The routing decision against join_table is fully spelled out.

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