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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: allowlists are per-leg, and omitting `ruleset` unions across legs. This goes beyond the schema by clarifying the default aggregation behavior. It doesn't describe pagination or return shape, but the output schema exists and the read-only nature is annotated.

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?

Three sentences, all informative and front-loaded with the core purpose. The first sentence states what it does, the second distinguishes it from the broader catalog, and the third explains the key parameter behavior. 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?

For a read-only list tool with a clear output schema, full parameter documentation, and annotations covering safety, the description is complete. It explains the one non-obvious behavior (per-leg allowlists and union behavior) that an agent would need to know to call it correctly. No significant gaps.

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 100%, so the schema already documents both parameters well. The description adds value by explaining the semantic effect of omitting vs. setting `ruleset` (union across legs vs. scoped to one leg), which reinforces and clarifies the schema's description. It doesn't add new parameter details beyond that, but the schema is already thorough.

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 tool lists rules the campaign DM has added to the campaign's allowlists, with a specific verb ('List') and resource ('rules... allowlists'). It also distinguishes itself from the broader vault catalog and from sibling tools like play_add_campaign_rule/play_remove_campaign_rule by focusing on listing allowed rules.

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 explicitly explains when to use the tool and how to vary behavior: omit `ruleset` to union rules across every leg, or set it to scope to one leg. It also notes this is a subset of the broader vault catalog, implying the alternative for broader catalog searches (vault_search_rules). This is clear usage guidance.

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