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

With readOnlyHint=false already signalling a state-changing action, the description adds the environmental precondition and where the id comes from. It says nothing about cost, cooldown, failure modes, or whether the player is moved immediately, so a mutation tool still has meaningful gaps.

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?

A single short sentence with the action front-loaded and the prerequisite in parentheses. Nothing is wasted, though cramming both the location requirement and the id source into parentheses is slightly dense.

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 one-parameter mutation with no output schema, the description covers the key prerequisite and parameter source. It is still thin on outcome behaviour — what success looks like, whether the id is consumed, or what errors can occur.

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 coverage is 0% with one opaque string parameter, so the description must carry the meaning. Saying portal_id is a 'direction id from game_look' is a genuine clarification that the schema lacks, but it does not explain the format or how to extract the id from game_look's output.

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 names a specific action (teleport through a portal) and its location context, which distinguishes it from siblings like game_move, game_enter_building, or game_mine_metro. It does not explicitly name an alternative tool, but the verb+resource is 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?

It states a precondition — the player must be inside the portal building — and points to game_look as the source of the direction id, which is useful routing. It gives no explicit when-not guidance or comparison against other movement tools such as game_enter_building or game_move.

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