update_collection_columns

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

With only readOnlyHint=false in annotations, the description carries the behavioral burden and does so well: it discloses the read-then-PATCH sequence and, critically, that the PATCH replaces the whole schema so omitting a column drops it. That non-obvious destructive side effect is exactly the kind of context annotations do not provide.

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, front-loaded with the purpose and immediately followed by the operational caveat. Every clause earns its place and nothing is repeated from the schema.

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 two-parameter mutation tool with no output schema, the description covers purpose, mechanism, and the destructive replace semantics. It omits permission/auth requirements and whether changes apply immediately, but nothing essential to invoking it 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%, so the baseline is 3, but the description adds real meaning: it clarifies that 'columns' is combined with system columns and that the supplied set replaces the existing schema, reinforcing the schema's 'FULL set' note with the drop-on-omission consequence.

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 names a specific verb and resource ('Add or change a collection's custom columns'), so the agent immediately knows this mutates a collection's schema. It does not explicitly contrast with any sibling (e.g., create_collection or update_collection if it exists), but the purpose is unambiguous.

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?

Usage is implied by the mechanism description ('Reads the current schema, then PATCHes it'), which tells the agent what the tool is for operationally, but there is no explicit when-to-use vs when-not or named alternative. No sibling overlap is flagged.

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