create_vector_index

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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only states that the tool creates an index. It fails to mention important details like potential table locking, the need for the column to have the vector type, or that this is an DDL operation that modifies the schema. The description adds no context beyond the bare action.

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 a single sentence that is front-loaded with the core purpose, containing no filler or redundant information. It is appropriately sized for a high-level tool overview, though other dimensions suffer from lack of detail.

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?

The tool is a DDL operation with 8 parameters, no annotations, and no schema descriptions, yet the description provides only a one-line overview. It fails to mention prerequisites, side effects, or index selection guidance, making it insufficient for agents to understand the full operational context. Even though an output schema exists, the tool's complexity demands a more complete description.

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 0%, so the description must compensate by explaining parameters. It only mentions 'HNSW or IVFFlat', which maps to the 'method' parameter, but leaves parameters like hnsw_m, metric, schema, and ivfflat_lists unexplained. The description adds minimal semantic value beyond what the schema already exposes through names and defaults.

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 action ('Create'), the specific resource ('vector index'), and the index methods ('HNSW or IVFFlat'), making the tool's purpose unmistakable. It distinguishes itself from sibling tools like list_vector_tables and similarity_search, which perform different operations on vector data.

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 implies when to use the tool (when you need an approximate-nearest-neighbor index on a vector column), but it does not provide explicit when/when-not guidance or mention prerequisites such as the pgvector extension or the column already containing vector data. No alternatives are discussed because the siblings are for different operations, but the lack of exclusion criteria leaves room for ambiguity.

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