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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description still adds real interpretive value by defining 'no_data' as not-yet-covered rather than known-safe, which prevents a dangerous misreading of empty results. It stops short of describing the response shape or how 'strongest evidence' is ranked.

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 tight sentences, with the core capability front-loaded and the 'no_data' caveat immediately after. No padding or restatement of the title.

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?

With no output schema, the description carries the burden of explaining returns, and it does so at a useful level: per-property presence/absence plus strongest evidence. It never specifies the exact field layout or how ties in evidence are resolved, a minor gap for a two-parameter read 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?

Schema description coverage is 100%, so both 'material' and 'properties' are documented in the schema, including their originating tools (search_materials, list_properties) and the 40-item cap. The description adds only the framing of 'one material and a list of properties', 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?

The description gives a specific verb-and-resource: for one material plus a property list it reports which properties have sourced data (with strongest evidence) and which have none. That is much clearer than the vague name 'what_is_missing'. It does not, however, explicitly contrast itself with siblings like get_material, whose output presumably overlaps.

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 implied: it's a coverage probe run before or instead of fetching data for a material. There is no explicit statement of when to choose it over get_material or compare, and no prerequisites mentioned beyond the parameter descriptions.

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