NEXO Brain

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

No annotations are provided, so the description carries full burden. It discloses key behavioral traits: it's a 'force full rebuild' (implying a potentially resource-intensive operation) and addresses search staleness. However, it doesn't mention performance impact, permissions needed, or whether it's asynchronous, leaving some gaps.

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 sentences with zero waste: the first states the purpose, the second provides usage guidelines. It's front-loaded and efficiently structured without unnecessary details.

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?

Given the tool's complexity (a rebuild operation), no annotations, and an output schema (which handles return values), the description is mostly complete. It covers purpose and usage but could better address behavioral aspects like side effects or execution time, slightly reducing completeness.

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?

The tool has 0 parameters with 100% schema description coverage, so the baseline is 4. The description doesn't need to explain parameters, and it appropriately doesn't add redundant information.

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 clearly states the specific action ('Force full rebuild') and target resource ('FTS5 search index'), distinguishing it from siblings like nexo_index_add_dir or nexo_index_remove_dir that manage index directories rather than rebuilding the index itself.

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?

Explicitly provides when-to-use guidance: 'after bulk changes or if search seems stale.' This gives clear context for invocation without needing to reference alternatives, as no direct sibling tools perform the same function.

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