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

Annotations already declare non-read-only, non-destructive, idempotent behavior, so the description's job is additive context, which it delivers: the previously active revision is preserved and re-activatable, and a pre-existing draft is returned with created: false. This explains the idempotency mechanism concretely rather than just restating the hint.

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 tight sentences, zero filler, and the core action is front-loaded. Each sentence adds a distinct fact: what is created, the editing/activation workflow, and the single-draft invariant.

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 mutation tool with annotations and no output schema, the description supplies everything an agent needs: the operation's effect, the follow-up tool chain, the safety guarantee for the existing revision, and the return-value edge case (created: false). Nothing material 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 both parameters are already documented in the schema, including the default-fork behavior of source_revision_id. The description reinforces the fork semantics ('or from source_revision_id') but adds no syntax or format detail beyond the schema, making the baseline 3 appropriate.

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 and resource ('Open a draft revision of a skill') and immediately defines the scope: files are copied from the active revision or from source_revision_id. It clearly differentiates itself from siblings by naming updateSkillRevisionFile, deleteSkillRevisionFile, and promoteSkillRevision as the operations that follow.

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?

Explicitly lays out the workflow: create the draft here, edit with updateSkillRevisionFile/deleteSkillRevisionFile, then activate with promoteSkillRevision. It also states the reuse condition — 'at most one open draft' — giving the agent a clear rule for when calling this is redundant.

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