Foreign Realm

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

Annotations already declare readOnlyHint=true, so the description does not need to restate that. The description adds value by detailing the returned data (ruler, army, allies, etc.) and acceptable input formats (full or partial names/title keys), which aids the agent in understanding behavior beyond the schema.

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 extremely concise: one sentence explaining the tool and a brief sentence directing to an alternative. Every word contributes value with no 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 simplicity (one required parameter, no output schema, no nested objects), the description is complete. It covers input format, output content, and provides a sibling alternative. No additional context is needed.

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% and already explains the parameter as 'realm name or title key, full or partial'. The description reinforces this with examples ('Scotland', 'k_france') but adds no new semantic information beyond what the schema provides.

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 verb 'look up' and the resource 'realm', specifies the input format (name or title key), and lists the returned information (ruler, army, etc.). It also distinguishes from the sibling 'realm_overview' by noting it is for one's own realm.

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 mentions when to use this tool ('look up any realm...') and directs the user to 'realm_overview' for their own realm, providing clear context for selection. However, it could elaborate on when not to use it beyond the own-realm case.

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