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

Beyond the annotations, it discloses the side effect that going public deletes every comment thread, the guard behavior (request refused unless delete_threads is true), and the replacement semantics of the share list. It also notes the return value (the URL), which the annotations cannot convey. The thread deletion sits in mild tension with destructiveHint=false, but because the operation is refused by default rather than silently destructive, this reads as disclosed opt-in behavior rather than a contradiction.

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 sentences, each carrying distinct load: purpose, list-replacement rule, destructive-change guard, return value. The most consequential caveat (thread deletion) is placed before the trivial return-value note.

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?

With an output schema present and full parameter documentation, the definition covers what an agent needs to call it safely, including the ownership precondition. The remaining gap is interaction between the listed flag and audience, and the ambiguity of supplying share_with alongside an explicit audience.

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, and the description genuinely adds semantics the schema does not: share_with is a complete replacement list and may be omitted to preserve the current one. It does not explain how listed interacts with audience, nor what happens if audience is passed with a share_with list, so it falls short of 5.

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?

"Set who can open an Artifact you own" gives a concrete verb plus resource and implicitly scopes itself to sharing rather than general editing. It stops short of naming the boundary against update_artifact, which also mutates artifact metadata, so an agent must still infer which one owns permission changes.

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 states the decision rule for audience, explains that share_with replaces rather than appends, and gives an explicit conditional for delete_threads (public change on a threaded artifact is refused unless true). What is missing is any comparison to a sibling tool for general artifact updates.

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