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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds useful scoping context ('this agent's active') that is not present in the annotations, clarifying that it returns a filtered subset rather than all possible subscription records.

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 a single, front-loaded sentence with no filler or redundant restatement. It conveys the action, the resource, and the scope in nine words.

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?

For a parameterless, read-only list operation, the description plus annotations fully equip an agent to select and invoke the tool. No return schema is provided, but the word 'List' sufficiently implies the output is the set of active subscriptions.

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?

With zero parameters and 100% schema description coverage, there is nothing for the description to add about arguments. The baseline of 4 for parameterless tools applies.

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 uses the specific verb 'List' with an explicit resource ('this agent's active event subscriptions'), making the tool's purpose unambiguous. It is clearly distinct from sibling tools like subscribe_event and unsubscribe, which perform mutations, and from data-retrieval tools like get_regime.

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 phrase 'this agent's active event subscriptions' clearly communicates the query scope and implies this is the tool to call when an agent needs to see its existing subscriptions. It does not explicitly name alternatives or exclusions, but no direct alternative for simply listing subscriptions exists among the siblings.

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