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

Annotations already declare readOnly/idempotent/openWorld, so the bar is lower, yet the description still adds value: hybrid word+meaning matching for query, proposed-first ordering without query, and guidance to quote only confirmed facts and verify stale ones. It does not discuss pagination behavior, though the schema's cursor/limit fields cover that.

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?

Four compact sentences front-load the tool's identity and matching behavior, then the downstream usage caution. Slightly dense but every sentence contributes; the stale-fact caution is the most tangential.

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 an output schema present and full annotation coverage, the description needn't cover return values. It supplies purpose, match semantics, ordering, alternative-tool routing, and usage caution, leaving no major gap for a 6-param filtered search.

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%, so baseline is 3. The description adds meaning beyond the schema by explaining that query does hybrid keyword+semantic matching and that omitting it returns everything with proposed facts first, giving the query parameter conceptual weight.

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?

States a specific verb (search) and resource (the brand's fact library), then defines the two fact states (confirmed vs proposed) so the agent understands the domain. It explicitly routes write operations to the sibling save_fact, distinguishing itself from it.

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?

Explains behavior with vs without query ('best matches by words and meaning' vs 'every fact, proposed first') and names save_fact as the alternative for adding/confirming/rejecting. It lacks explicit steering against other search siblings like search_docs or search_site, but the write-vs-read context is clear.

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