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

No annotations are supplied, so the description carries the full burden. It does disclose the single most important non-obvious behavior: the unspent balance remains as credit and is not refunded. It says nothing about whether closing is reversible, what happens on a second close, or what the call returns.

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?

Two short sentences, front-loaded with the action and immediately followed by the money consequence. Only waste is the 'mission'/'room' inconsistency, which slightly muddies an otherwise tight statement.

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 mutation tool with zero annotations and no output schema, the description covers the key financial side effect but leaves out irreversibility, authorization expectations, and error/return behavior. Adequate but with clear gaps.

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 room_id and owner_key are already documented in the schema. The description adds no meaning about the required owner_key authorization or any parameter constraints, so 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: 'Close the current mission' (i.e., the room). An agent can tell this is the terminating counterpart to create_room, though the description says 'mission' where the tool name and schema say 'room', which introduces minor terminology drift.

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 parenthetical '(no automatic refund)' implies that an agent wanting money back should use the request_refund sibling instead, but that alternative is never named and no explicit when-to-use or when-not-to-use condition is given. Usage is implied rather than stated.

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