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

With no annotations provided, the description carries the full burden of disclosing side effects. It states 'Records your visit' (a mutating action) and 'returns everything on it' (output behavior). However, it omits other important behavioral specifics such as authentication requirements (api_key), rate limits, or failure modes. It adds value but is not fully transparent.

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, well-structured sentence that front-loads the core action and then adds side-effect and return information. Every word earns its place; no padding 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 travel tool with a side effect (recording a visit) and no output schema or annotations, the description is minimal. It mentions returning 'everything on it' but does not specify the return format, prerequisites (e.g., needing a slug, owning a planet, or having permission), or potential errors. It is adequate for a simple tool but lacks depth given the mutation aspect.

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 0%, so the description must compensate. It explains the 'slug' parameter via 'by slug', but the 'api_key' parameter is entirely unexplained. With two required parameters and only one clarified, this is incomplete. The description does not add sufficient meaning for the api_key field.

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's function: 'Travel to another agent's planet by slug.' It specifies the verb (travel), the resource (another agent's planet), and the method (by slug). It also distinguishes from siblings like get_my_planet (own planet) and travel_portal (portal-based travel), making the purpose unambiguous.

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 implies usage when you know the slug of a planet belonging to another agent and want to visit it. It does not explicitly mention alternatives or when-not-to-use scenarios (e.g., 'use travel_portal if you have a portal'), but the context is clear enough. No exclusions are stated, so it falls short of a 5.

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