rag_index

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

With no annotations, the description does real work: it discloses incremental rebuild behavior, skipping unchanged files, and the default that omitting source updates all four source types. It does not mention permissions, expected duration, or side effects beyond index mutation, but it covers the core behavior well.

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?

Three short sentences, no filler, and the incremental behavior is front-loaded. Each sentence adds operational value: behavior, alternative, and default scope.

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 one-parameter indexing tool with full schema coverage and no output schema, the description covers the essential decision points: incremental update, full-rebuild alternative, and default scope. It could say more about mutation side effects or permissions, but nothing critical is missing.

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 the baseline is 3, but the description adds useful semantics beyond the schema by stating that omitting source updates all four source categories. That default behavior is not fully conveyed by the schema alone.

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 verb and resource: incrementally updating the RAG index. It immediately clarifies the key behavior—only changed content is rebuilt, unchanged files are skipped—and distinguishes this from a full CLI rebuild, which is enough to separate it from the read-oriented siblings rag_open, rag_stats, and rag_search.

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?

It explicitly says when to use this tool versus an alternative: use it for incremental updates, but use the command line for initial indexing or when many files changed. That is concrete when/when-not guidance rather than implied usage.

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