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

With no annotations, the description carries the full behavioral burden. It usefully discloses that the operation does not persist ("not added to the city") and that it returns a url_hash for opening the preview, but it says nothing about permissions, authentication, rate limits, or whether repeated calls are cached or costly.

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?

Three short sentences: the core action and metaphor come first, the non-persistence constraint second, and the practical url_hash usage last. The structure is front-loaded and mostly free of waste, though the metaphor adds a little interpretive overhead.

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 three-parameter preview tool with no annotations and no output schema, the description does explain the key return value (url_hash) and the non-persistent behavior. However, it leaves the required handle parameter and the github toggle unexplained, and gives no sense of side effects or preconditions beyond non-persistence.

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 67%: lang and github have schema descriptions, while the required handle parameter is undocumented in both schema and description. The description only implicitly connects the action to a user handle and GitHub data, so it does not meaningfully compensate for the gap.

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 states a specific verb and resource ("Builds a user's building") and explains the domain metaphor (repositories become rooms). It also implicitly distinguishes itself from get_building by noting the result is a preview that is not persisted, though it does not name the sibling explicitly.

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 non-persistence note ("not added to the city") implies this is for previewing before committing or fetching an existing building, but there is no explicit when-to-use guidance or named alternative among the many sibling tools such as get_building or get_street.

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