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

Annotations already declare this as a mutating and destructive operation; the description adds value beyond them by disclosing that only DRAFT versions can be modified (attempts on others presumably fail) and that omitted fields are left untouched. That partial-update/PATCH semantic is genuinely useful behavioral context.

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?

Three terse sentences with zero filler. The verb and resource lead, followed by the draft-only constraint and the partial-update semantic. Every sentence earns its place and the most critical facts are 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?

For a simple 5-param, no-output-schema tool, the description covers the two highest-risk behaviors: the draft-only restriction and partial updates. It doesn't mention return values or error behavior on non-draft targets, but those are minor given the tool's simplicity and the strong schema coverage.

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. The description compensates above baseline with 'Only provided fields are changed,' which clarifies that omitting optional parameters (effectiveTo, commitMessage, effectiveFrom) preserves their existing values rather than clearing them. This meaningfully enhances how an agent interprets the optional params.

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 states a specific verb and resource — 'Update a DRAFT version' — and adds the key scoping constraint that only DRAFT versions are modifiable. This differentiates it from sibling operations like create, delete, clone, or list, though it doesn't name them explicitly.

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?

'Only DRAFT versions can be modified' gives a clear when-not condition: this tool is inappropriate for published or active versions. The partial-update sentence also sets expectation about behavior, but no alternative tool is named for non-draft cases.

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