getEmbeddingIndexStats

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine behavioral meaning beyond that: the operation is a non-destructive progress probe whose readiness semantics depend on comparing two returned counters.

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: the first defines the return payload, the second defines the usage trigger. Nothing is wasted and the most decision-relevant information is front-loaded.

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?

An output schema exists, so return values need no elaboration, and the description still supplies the interpretive rule (indexedRecords === totalRecords means ready) that a raw output schema could not convey. Nothing needed to call this correctly 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% and the schema itself documents indexId, including that an ID or name from findEmbeddingIndexes is accepted. The description adds no parameter-level detail, so this is the baseline case where the schema does the work.

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+resource ('Return indexing statistics for an embedding index') and even names the two returned fields, totalRecords and indexedRecords. This separates it cleanly from siblings like findEmbeddingIndexes, createEmbeddingIndex, and deleteEmbeddingIndex.

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?

Gives explicit context: use it to monitor backfill progress after creating an index, with the concrete readiness condition indexedRecords === totalRecords. It does not name when-not to use it or point to an alternative tool for other index questions, so it falls just short of 5.

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