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

Beyond the readOnlyHint annotation, the description discloses several non-obvious behaviors: the scope is 'owned by the calling API key,' ordering is 'most recently updated first,' anonymous calls return an empty list, and temporary anonymous projects are never listable. These are meaningful behavioral traits that are not already captured by the annotation or schema.

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 three sentences with no waste. The first sentence delivers the primary purpose and ordering, the second adds a critical edge case about anonymous calls, and the third states the authentication requirement. Every sentence earns its place, making it both concise and well-structured.

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 list tool with five parameters, an output schema, and a readOnly annotation, the description is complete. It covers the core functionality, authentication requirements, and the key anonymous edge case. The output schema handles return value details, and the schema covers parameter semantics, so no critical information is missing for an agent to correctly select and invoke this tool.

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?

The input schema already provides 100% coverage with detailed descriptions for all five parameters. The tool description adds no per-parameter meaning beyond this, but it does provide context about the list's default ordering which indirectly relates to updated_since. Per the rubric, baseline 3 is appropriate since schema does the heavy lifting.

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 lists durable house projects owned by the calling API key, with a specific sort order ('most recently updated first'). It explicitly distinguishes from related operations by noting anonymous calls return an empty list and temporary projects are not listable, directly separating it from project_get or project_delete in the sibling set.

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?

Provides clear usage context: requires an API key, and anonymous keyless calls always return an empty list, with temporary projects to be resolved directly via house_ref instead. While it doesn't explicitly name an alternative tool like project_get, the guideline is sufficiently clear for an agent to know when not to use this tool and what to do instead.

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