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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. The description adds useful behavioral context beyond that: visited systems are marked, and player counts are deliberately excluded from the map — non-obvious traits an agent would otherwise have to discover.

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?

Single front-loaded sentence with the primary action first, followed by return-content details. The parenthetical packing of several facts is slightly dense but no sentence 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?

With no output schema, the description carries the return-value burden and does so: coordinates, connections, visited markers, and the absence of player counts. Nothing critical is missing for a read-only lookup tool.

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 both parameters (system_id, session_id) are already documented. The description restates system_id's optional behavior without adding format, validation, or semantics beyond the schema; baseline 3 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?

States a specific verb and resource with scope: 'View all star systems in the galaxy', plus what it returns. It distinguishes itself somewhat via 'The map shows no player counts', but never names siblings like get_system or search_systems that an agent might confuse it with.

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?

It explains the two modes (omit system_id for all systems, pass it for one), which is implied usage guidance, but gives no when-to-use/when-not-to-use versus alternatives such as search_systems, get_system, or get_nearby.

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