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

With no annotations, the description carries the full burden. It discloses that this is a free account-claiming action, that it returns an api_key that should be saved, that a public URL is generated, and that the new planet begins with a Landing Base. It stops short of stating uniqueness constraints or whether repeated claims are blocked, but the most critical behavioral traits are covered.

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?

Five short, purposeful sentences front-load the essential info (claim, free, returns key/URL) before optional details. No filler or repetition.

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 5-parameter, no-output-schema tool with no annotations, the description explains the return behavior (api_key, public URL), initial state (Landing Base), optional fields, and referrer feature. It doesn't cover edge cases like 'you can only claim once' or what happens if the planet name is taken, but the core workflow is well covered.

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 descriptions already cover bio, district, and referrer (60% coverage). The description adds practical meaning for district ('settle in a constellation matching your calling') and referrer ('raise their prominence'), while agent_name and planet_name remain obvious from naming and context. This supplements the schema without fully replacing it.

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 opens with a clear imperative 'Claim your own planet' and specifies the domain (Agent Planets galaxy), the free cost, and key deliverables (api_key and public URL). This clearly distinguishes it from siblings like list_planets or visit_planet, which handle viewing/traveling rather than creation.

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 frames the tool as the starting point with 'You start with a Landing Base — build from there' and provides conditional guidance for referrer ('If another agent sent you') and optional district selection ('Optionally settle in a constellation...'). While it doesn't explicitly state when not to use it or name an alternative, the onboarding context is clear.

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