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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the bar is lower. The description still adds real value: it discloses the return value (draftId), the create/update branching mechanism, and that payloads may be partial. It does not state anything that contradicts the annotations.

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?

Four dense sentences, front-loaded with the purpose before the create/update mechanics and payload list. No filler, though the trailing 'Keys accepted in...' sentences restate structure the schema already nests and could be tightened.

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 an 18-parameter, nested-object mutation with no output schema, the description covers purpose, branching, payload groups, and the return value (draftId). The remaining gaps — no mention of the required `site` or the remix/`urls` path — are real but partly recoverable from the schema's own descriptions and enums.

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 44%, so the schema documents some parameters (articleType, link/video options, locationId) but leaves many bare. The description enumerates the acceptable payload groups and gives the nested shapes for outline and article, adding some meaning, but it never mentions the required `site` parameter or `urls`/remix handling, so it only partially compensates.

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 (store/save) and resource (Article Builder draft) plus the persistence intent ('so a human or a later session can pick it up in the dashboard'), which separates it from the read siblings get_builder_draft/list_builder_drafts and the publish sibling. An agent can identify it 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?

Gives the key use case and the create-vs-update condition explicitly: 'Create a new draft (omit draftId) or update one.' 'Send only what you have' clarifies partial saves. It stops short of naming sibling alternatives (get_builder_draft, delete_builder_draft) or prerequisites, so it is clear context without exclusions.

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