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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real value beyond them by disclosing the auth requirements (claimed credential and claimed workspace) and the exact failure semantics (403 for unclaimed sandbox keys, 404 for missing/non-draft orders). It does not say what activating actually changes on the order or whether it can be undone, but given the annotation coverage of idempotency and non-destructiveness this is solid supplementary 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 short sentences, action stated first, which is good front-loading. The credential and workspace sentences are dense and slightly clipped (e.g. 'Needs a claimed Last Price credential'), reading like terse notes rather than polished guidance, but little is wasted.

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 no output schema the description should convey what a successful call produces or changes, and it only implies a draft-to-active transition without stating effects on the order. It does cover the two things an agent most needs — preconditions and error codes — so it is adequate but not complete for a mutation 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?

Only one parameter and schema description coverage is 100%, so the schema already documents order_id as the UUID 'as list_orders shows it'. The description reinforces that with 'pass order_id' but adds no format or sourcing details beyond the schema, so it sits at the baseline-plus level rather than contributing new semantics.

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?

Specific verb ('Activate') and resource ('a draft order'), with the scope narrowed to drafts, which tells an agent this is a state transition rather than a generic update. It never names a sibling such as update_order or get_order to sharpen the boundary, so it stops short of full differentiation.

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 states the preconditions: a claimed Last Price credential and a claimed workspace, with the self-registration sandbox key path called out as refused with 403. It also explains the 404 condition (order missing or no longer draft), which tells the agent what a failure means. No guidance on when to prefer this over update_order, hence not a 5.

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