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

Annotations cover the safety profile (readOnly=false, destructive=false, non-idempotent), so the description's job is additive context — and it delivers: the copy is configuration-only and the knowledge will not function until agent_train runs, plus a plan-level "Agents" permission is required and cross-account placement is owner-restricted. It does not say whether the duplicate is created active/paused or how it is named, which are the main remaining behavioral gaps.

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 front-loaded sentences: purpose, then the critical post-copy caveat, then the permission/ownership constraints. Nothing is wasted and the most decision-relevant warning (needs agent_train) comes early.

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 only two parameters, full schema coverage, and no output schema, the description covers what an agent needs to invoke it correctly and not be surprised afterwards. It is missing only the return value (presumably the new agent id) and whether the copy inherits settings like status, both of which matter for a duplication tool.

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 100% and the userId schema text is far more precise than the description (naming subaccount_list, forbidding guessed ids, requiring a user confirmation). The description's "optionally into a sub-account" and "account owner" only restate that at a higher level, and it says "account owner" where the schema says "agency owner" — a loose summary rather than added meaning. Baseline 3 applies.

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?

"Copy an agent, optionally into a sub-account" states a specific verb (copy/duplicate) and resource (agent) with an explicit scope option. An agent can immediately tell this apart from agent_upsert, agent_get, or agent_delete without opening any 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 clear context: it names agent_train as the mandatory follow-up step before the knowledge works, and states the owner-only precondition for the cross-account variant. It stops short of naming an explicit alternative tool or a "do not use this when..." exclusion, but the post-copy routing guidance is genuinely actionable.

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