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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false, so the safety profile is covered. The description adds genuinely useful behavior the annotations cannot convey: existing rows keep their values, new columns are null until upserted, and a type change is validated against every existing row first.

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?

Front-loaded with the core operation, then consequences, then the key constraint; sentences are dense but each carries information. The 'Keep descriptions true' sentence is slightly tangential but serves as actionable guidance rather than filler.

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 destructive 7-parameter mutation tool with no output schema and full annotation coverage, the description supplies the data-preservation semantics an agent needs to act safely. It stops short of describing ordering when multiple mutation fields are passed together, which is a minor gap.

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 meaning beyond the schema by mapping intents to parameters (type/description fixes go through update_columns) and by stating a constraint absent from the schema — that the dataset key is immutable. It still does not disambiguate add_columns versus update_columns when a column exists but is being retyped.

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 and enumerates the exact mutation categories (add/remove columns, update column description or type, change dataset description or cadence), which clearly separates it from create_dataset and delete_dataset. An agent can tell what this tool does without opening the schema.

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 routes the agent for one important case — 'The key cannot be changed; create a new dataset for that' — and implicitly points at upsert_rows by noting new columns stay null until values are upserted. It does not, however, explicitly state when to prefer this over upsert_rows or create_dataset in general.

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