background_search

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

With no annotations provided, the description carries the transparency burden. It clearly conveys a read-only search that returns a list of matching entries, but it does not disclose aggregate behaviors such as partial matching, default ruleset filtering, or how homebrew content is treated beyond what the schema parameters imply.

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 short sentences with no filler. Purpose, result type, and routing guidance are all front-loaded and each sentence earns its place.

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 search tool, the description plus fully documented schema parameters are sufficient for correct invocation. The return shape is stated as a list of matching entries, and the omnisearch routing rule addresses the main ambiguity among sibling tools.

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 the baseline is 3. The description only reinforces the 'by name' query semantics without adding new meaning beyond the schema's parameter descriptions.

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 states a specific action ('Search'), a precise resource ('D&D 5e character backgrounds'), and the matching criterion ('by name'). It also distinguishes itself from the broad omnisearch sibling by explicitly referencing content-type awareness.

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 final sentence gives an explicit decision rule: use this tool when the content type is known and use omnisearch instead when unsure. This directly helps an agent choose between background_search and the fallback sibling tool.

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