Element detail by GlobalId

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

Annotations already cover the read-only/open-world safety profile, but the description goes further by disclosing how unresolved ids surface in `not_found` and that 'no such element' and 'hidden by policy' are deliberately conflated to avoid leaking filtered shape. That is genuinely non-obvious behavioral context an agent could not infer from annotations 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?

Two short paragraphs, front-loaded with the core action followed by the error-semantics detail. The em-dash clause about not leaking filtered shape is slightly ornate but still load-bearing information.

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?

No output schema exists, so the description must convey what comes back — and it does: full property sets, quantities, materials, plus the `not_found` bucket. With only two well-documented parameters, an agent has everything needed to call this correctly.

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 both `ids` and `max_ids` are already documented, and the description adds little parameter-level detail beyond calling them 'named GlobalIds'. Baseline 3 is appropriate when the schema carries the semantics.

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?

Specific verb ('expands') plus resource ('named GlobalIds into every property set, quantity and material'), and it explicitly frames itself as the drill-down counterpart to the compact list queries, which cleanly separates it from siblings like bim_elements_by_type and bim_property_values.

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 'drill-down half of the loop' framing tells the agent this follows a list query, which is clear usage context. It stops short of naming a specific sibling or stating exclusions (e.g. when to prefer bim_property_values instead), so it falls just below the top score.

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