Reindex into another index

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

The description goes beyond the annotations by disclosing the crucial asynchronous behavior: it returns a task id immediately while the copy continues, and it tells the caller how to poll progress. Annotations already cover read/write/destructive aspects, and the description adds meaningful operational context without contradicting them.

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: the first states the action clearly, and the second adds the key behavioral caveat and how to follow up. No filler or repetition of schema content.

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 tool with nested parameters and no output schema, the description explains the main return signal (task id) and the continuation mechanism. It is sufficient for an agent to select and invoke the tool correctly, though it does not detail edge cases or result formats beyond the task id.

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%, and the schema already documents sourceIndex, destIndex, query, and script with meaningful descriptions. The tool description adds no parameter-specific detail, but the schema carries that burden fully, so the baseline 3 is appropriate.

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 uses a specific verb and resource pair: 'Copy documents between indices.' This clearly distinguishes reindex from read-only search, single-document get, and indexing/bulk operations, and the title reinforces the same intent.

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 description clearly implies when to use this tool: when documents must be copied between indices. However, it does not explicitly explain when not to use it or mention alternatives such as bulk for direct writes or search for read-only queries. The async polling hint gives practical usage context, but no explicit routing guidance.

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