get_build_size_estimate

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

With no annotations, the description must carry the behavioral load. It adds useful context — this is an approximation ('estimate') scoped to scene-referenced assets, and it returns largest assets — but it never states that it is a read-only operation, whether it is expensive or slow, or that unreferenced assets are excluded.

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 front-loaded sentence with no filler; the colon-plus-list structure delivers the core purpose first. It is telegraphic enough that the 'largest assets' clause reads slightly ambiguously as either the output or the top_n control.

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-optional-parameter read tool with no output schema and no annotations, the description covers what is aggregated, the scope (build scenes), and the shape of the result (total size plus largest assets). Missing only the read-only/expense disclosure and any routing to alternatives.

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 100% and top_n is already documented in the schema with its default of 20. The description's mention of 'largest assets' corresponds to that parameter but adds no syntax, bounds, or interaction detail, so the 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 gives a specific verb (estimate) and resource (build size) and then unpacks the computation: assets referenced by all build scenes, total size, and largest assets. That is enough to distinguish it from siblings like get_unused_assets_estimate without opening the schema, though it never names those siblings 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?

Usage is only implied: the phrase 'referenced by all build scenes' hints that this is a scene-scoped projection of build size, but there is no statement of when to prefer it over get_unused_assets_estimate or get_build_report_summary, and no prerequisites or exclusions.

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